| 1. |
- da Cruz Francisco, José, et al.
(författare)
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Phase behavior of the monoolein-water system - The effects of addition of the hydrocarbon 1,8-cineole and supercritical carbon dioxide
- 2004
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Ingår i: Journal of Supercritical Fluids. - : Elsevier BV. - 0896-8446. ; 31:3, s. 263-271
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Tidskriftsartikel (refereegranskat)abstract
- The results of a study on the phase behavior of the monoolein/water system with the addition of the hydrocarbon 1,8-cineole (C10H18O) and supercritical carbon dioxide at 15 MPa is presented. To two mixtures consisting of 9 and 18 wt.% water in monoolein, 5, 10, and 20 wt.% cineole were added and heated to between 35 and 80 degreesC at atmospheric pressure and in the presence of supercritical carbon dioxide. The phase changes were followed by deuterium nuclear magnetic resonance (H-2 NMR), light microscopy, and ocular inspection. The mesomorphic structures developed in the 9 wt.% water sample suffered little change due to the presence of the supercritical carbon dioxide. However, in the mixture with 18 wt.% water, the native phase structures were dramatically affected and an isotropic fluid phase developed. The addition of cineole has lowered the LC-L-alpha --> LC-H-Pi phase transition in the samples with 9 and 18 wt.% water in monoolein. The surplus of supercritical carbon dioxide in the samples has resulted in similar developments. Regardless of the amount of cineole present in the system, only the isotropic fluid phase was observed in the samples with 18 wt.% water in monoolein. (C) 2004 Elsevier B.V. All rights reserved.
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| 2. |
- da Cruz Francisco, José, et al.
(författare)
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Phase behavior of the system lecithin-water - The effects of addition of the hydrocarbon 1,8-cineole and supercritical carbon dioxide
- 2004
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Ingår i: Journal of Supercritical Fluids. - : Elsevier BV. - 0896-8446. ; 31:3, s. 255-262
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Tidskriftsartikel (refereegranskat)abstract
- The phase behavior of lecithin and water mixtures with addition of the hydrocarbon 1,8-cineole (C10H18O) was investigated using light microscopy and H-2 NMR at atmospheric pressure and with a surplus of supercritical carbon dioxide (15 MPa) between 35 and 80degreesC. The lecithin-water (LW) mixtures consisted of 10 and 20wt.% water in lecithin to which 5, 10, and 20wt.% cineole and supercritical carbon dioxide were added. The addition of cineole to the 10wt.% water in lecithin samples has affected the original lamellar liquid crystalline phase present and mainly transformed it into the reversed hexagonal phase at cineole concentration of 10wt.% and higher. This phase however Only Occurred when 20 wt.% cineole were added to the lecithin samples with 20wt.% water which otherwise was lamellar. The addition of supercritical carbon dioxide to the lecithin/water samples in the absence of cineole resulted in a liquid crystalline lamellar (LC-L-alpha) phase and was the same as in the original phase structure at atmospheric pressure. In the lecithin/water samples with cineole, the addition of supercritical carbon had little effect on the structure. (C) 2004 Elsevier B.V. All rights reserved.
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| 3. |
- Francisco, J D, et al.
(författare)
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Liquid crystalline properties and extractability of monoolein-water systems by supercritical carbon dioxide
- 2003
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Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - 0927-7757. ; 213:1, s. 69-78
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Tidskriftsartikel (refereegranskat)abstract
- The influence of phase structure on the extraction recovery of monoolein from monoolein-water systems by supercritical carbon dioxide was investigated. Two monoolein-water mi tures at concentrations of 9 wt% water and 18 wt% water, respectively, were studied. H-2-NMR was used to monitor changes of the phase structures in supercritical conditions. The results showed that the phase structure and the water-monoolein interactions play a role on the extraction yield. The monoolein recovery was higher in the 9 wt% water sample in which L-alpha phase was present compared to the 18 wt% water sample in which the L-alpha melted to yield a L-2 phase. When the phase structures were the same in both samples, the extraction recovery was determined by the solubility properties of the components of the system. The changes due to the presence of supercritical carbon dioxide were shown also to depend on the water concentration of the monoolein-water mixture besides the temperature. The 18 wt% mixture showed a L-2 phase structure in all the range of the temperature investigated while the 9 wt% water mixture showed phase changes from L-alpha phase to L-2 phase in the same temperature range. (C) 200 Elsevier Science B.V. All rights reserved.
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| 4. |
- Lin, Qin-Lu, et al.
(författare)
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Effect of colloidal structures on the stability of five flavonoids with different hydrophilicity
- 2008
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X. ; 22:4, s. 700-705
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Tidskriftsartikel (refereegranskat)abstract
- Autoxidation of five flavonoids representing range of different hydrophilicities (epicatechin gallate (ECG), (+) catechin((+)Q, epicatechin (EC), epigallocatechin gallate (EGCG) and epigallocatechin (EGC)) in three different aqueous solutions: molecular solution, micellar solution (Tween 20) and liposoml dispersion (soybean lecithin) was monitored by HPLC. The rate of oxidaton of the five flvonoids was higher at pH 4.5 than at pH 3.5. Compared with the control, addition of Tween-20 (micellar structure) and lecithin (liposomal structure) significantly decreased the degradation of flavonoids. In the presence of lecithin the autoxidation of all the five flavonoids was slower than in the presence of Tween-20. The effective protection of the colloidal structures was compared the hydrophilicity of the flavonoids estimated from the partitioning between octanol and water. The protection from oxidation in the presence of the colloidal structures (micellar or liposomal) increased with increasing partitioning of a flavonoid towards the hydrophobic environment. The protecting effect of the colloidal structures was more effective at pH 4.5 than at pH 3.5.
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| 5. |
- Penarrieta, Mauricio, et al.
(författare)
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Total antioxidant capacity and content of flavonoids and other phenolic compounds in canihua (Chenopodium pallidicaule): An Andean pseudocereal
- 2008
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Ingår i: Molecular Nutrition and Food Research. - : Wiley. - 1613-4133 .- 1613-4125. ; 52:6, s. 708-717
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Tidskriftsartikel (refereegranskat)abstract
- Total antioxidant capacity (TAC), total phenolic compounds (TPH), total flavonoids (TF) and individual phenolic compounds were determined in canihua collected at approx. 3850 in altitude. The TAC values varied among samples from 2.7 to 44.7 by the ferric reducing antioxidant power (FRAP) method and from 1.8 to 41 by the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method expressed as mu mol of Trolox equivalents/g dw. The content of TPH was 12.4-71.2 mu mol gallic acid equivalents/g dw and that of the TF ranged between 2.2 and 11.4 mu mol of catechin equivalents/g dw. The data obtained by the four methods showed several significant Correlations. Prior to analysis by HPLC, the samples were subjected to acid hydrolysis and in the water-soluble extracts this led to an up to 20-fold increase in the TAC values in comparison with the values of the nonhydrolysed samples. HPLC analysis showed the presence of eight major compounds identified as catechin gallate, catechin, vanillic acid, kaempferol, ferulic acid, quercetin, resorcinol and 4-methylresorcinol. Their estimated contribution to the TAC value (FRAP method) indicated that resorcinols contributed most of the antioxidant capacity of the water-soluble extract. The results show that canihua is a potential source of natural antioxidant compounds and other bioactive compounds which can be important for human health.
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| 6. |
- Penarrieta, Mauricio, et al.
(författare)
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Total Antioxidant Capacity and Content of Phenolic Compounds in Wild Strawberries (Fragaria vesca) Collected in Bolivia
- 2009
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Ingår i: International Journal of Fruit Science. - : Informa UK Limited. - 1553-8362 .- 1553-8621. ; 9:4, s. 344-359
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Tidskriftsartikel (refereegranskat)abstract
- To study the composition of wild strawberries grown at high altitude, total antioxidant capacity, total phenolic compounds, total flavonoids, and individual phenolic compounds were measured in wild strawberries (Fragaria vesca) collected between 2,650 and 3,300 m above sea level in Bolivia. Total antioxidant capacity, as assessed by the ferric-reducing antioxidant power and 2,2¢-azinobis( 3-ethylbenzotiazoline-6-sulphonic acid) methods, was in the range 16-39 mmol of Trolox equivalents/g fw by both methods. The total phenolic content was 9.7–21 mmol gallic acid equivalents/g fw, and the flavonoid content ranged between 2.8 and 4.9 mmol of catechin equivalents/g fw. The data obtained by the four methods showed several significant linear correlations confirming that flavonoids and other phenolic compounds contributed significantly to the total antioxidant capacity values. Reversed-phase high performance liquid chromatography analysis of extracts subjected to acid hydrolysis showed the presence of seven major fractions, tentatively identified as ellagic acid, cyanidin, pelargonidin, quercetin, kaempferol, gallic acid derivatives, and catechin derivatives. The data indicated that wild strawberries have a somewhat higher total antioxidant capacity content in comparison with that reported for cultivated strawberries. No obvious difference to the composition reported for wild strawberries grown at low altitude could be found.
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| 7. |
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| 8. |
- Alftrén, Johan, et al.
(författare)
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Comparison of molecular and emulsifying properties of gum arabic and mesquite gum using asymmetrical flow field-flow fractionation
- 2012
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X. ; 26:1, s. 54-62
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Tidskriftsartikel (refereegranskat)abstract
- The molecular and emulsifying properties of gum arabic (GA) and mesquite gum (MG) were characterized using asymmetrical flow field-flow fractionation connected to multi-angle light scattering and refractive index detection. Properties such as molar mass, root-mean-square radius (rrms), hydrodynamic radius (rh), conformation, apparent densities and distribution of proteinaceous matter over the whole molar mass range were determined. GA displayed a low molar mass (3.4 × 105 g/mol), protein-poor component (population 1) and a high molar mass (1.9 × 106 g/mol), protein-rich component (population 2). MG displayed one molar mass population with an average molar mass of 1.1 × 106 g/mol. For both GA and MG, the conformation (rrms/rh) was increasingly spherical with increasing molar mass. However, MG had higher values of rrms/rh for a specific molar mass suggesting differences in structure between GA and MG. The protein content increased with increasing molar mass for both gums, although to a higher extent for GA. Selective adsorption, during emulsification experiments, could be observed of population 2 of GA which may be due to a combination of the higher protein content and a more flexible structure rendering it more surface active than population 1. Comparing GA and MG in terms of emulsion stability, it could be concluded that GA-stabilized emulsions have considerably higher stability against coalescence.
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| 9. |
- Andersson, Ida Marie, et al.
(författare)
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Effects of feed composition, protein denaturation and storage of milk serum protein/lactose powders on lactosylation
- 2021
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Ingår i: International Journal of Food Science and Technology. - : Wiley. - 0950-5423 .- 1365-2621. ; 56:1, s. 480-492
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Tidskriftsartikel (refereegranskat)abstract
- During whey powder production, the feed is subjected to several heat treatments which can cause lactosylation of proteins. In this study, lactosylation of whey proteins was evaluated in spray-dried powders before and after storage by varying the native protein fraction as well as the serum protein/lactose ratio in the powders. The lactosylation of native α-lactalbumin and β-lactoglobulin in the powders before storage was not affected to a large extent by the protein denaturation or if the feed had been heat treated in a high or low lactose environment. After storage (relative humidity of 23.5%, 30 °C, 25 days), the kinetic of lactosylation tended to increase with increasing native protein fraction and bulk protein content in the powders. An explanation could be that proteins dissolved in the lactose glassy structure might have a lower reactivity, while proteins present in the protein glassy structure with dissolved lactose may display higher lactosylation reactivity.
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| 10. |
- Andersson, Kristina E, et al.
(författare)
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Effects of oats on plasma cholesterol and lipoproteins in C57BL/6 mice are substrain specific.
- 2010
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Ingår i: British Journal of Nutrition. - 1475-2662. ; 103, s. 513-521
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Tidskriftsartikel (refereegranskat)abstract
- Cholesterol-lowering effects of oats have been demonstrated in both animals and human subjects. However, the crucial properties of oat-containing diets that determine their health effects need to be further investigated to optimise their use. A mouse model would be a valuable tool, but few such studies have been published to date. We investigated the effects of oat bran on plasma cholesterol and lipoproteins in two substrains of C57BL/6 mice. Western diet was made atherogenic by the addition of 0.8 % cholesterol and 0.1 % cholic acid. After 4 weeks on atherogenic diet, total plasma cholesterol had increased from 1.86-2.53 to 3.77-4.40 mmol/l. In C57BL/6NCrl mice, inclusion of 27 and 40 % oat bran reduced total plasma cholesterol by 19 and 24 %, respectively, reduced the shift from HDL to LDL+VLDL and caused increased faecal cholesterol excretion. There was no effect of oat bran on plasma levels of the inflammatory markers fibrinogen, serum amyloid A or TNF-alpha. Contrary to findings in C57BL/6NCrl mice, there was no sustained effect of oat bran (27 or 40 %) on plasma cholesterol in C57BL/6JBomTac mice after 4 weeks of feeding. Thus, C57BL/6NCrl mice fed an atherogenic diet are a good model for studies of physiological effects of oats, whereas a substrain derived from C57BL/6J, raised in a different breeding environment and likely possessing functional genetic differences from C57BL/6N, is considerably less responsive to oats. The present finding that two substrains of mice respond differently to oats is of practical value, but can also help to elucidate mechanisms of the cholesterol-lowering effect of oats.
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| 11. |
- Bai Palmkron, Shuai, et al.
(författare)
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Quantification of structures in freeze-dried materials using X-ray microtomography
- 2023
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Ingår i: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 658
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Tidskriftsartikel (refereegranskat)abstract
- The structure of a freeze-dried material is essential for its ability to preserve and protect biologics such as proteins, cells and other sensitive structures. The structure of a typical freeze-dried matrix can be described as pores surrounded by thin walls where the walls are the encapsulating material (for e.g. cells). The objective of this investigation is to evaluate X-ray microtomography (µCT) as a characterization method to quantifying the matrix of a freeze dried material, and compare it to scanning electron microscopy (SEM). The material consists of maltodextrin, freeze-dried below or above the glass transition temperature of the maximal freeze concentration (Tg′) and after applying annealing. The SEM images have high resolution and provide an excellent view of the sample. However, it is challenging to perform any image analysis and to ensure that a representative section is presented. The µCT images provide a rather uniform contrast between material and void, allowing for a simple grey-level thresholding when separating structure from the background. A robust image analysis procedure allows the results extracted from a representative sample volume to be evaluated. Further image analysis has been focused on understanding the thickness of the encapsulating structures by estimations of volume-weighted averages of inscribed spheres within the walls. The results show two types of structures: A large pore structure of around 20–100 µm separated by thin walls around 2–3 µm thick, and a finer structure consisting of smaller pockets of air (< 10 µm) packed in a honeycomb like structure. The structures of the samples dried below and above Tg′ have smaller and thinner structures, while material dried after annealing has larger and thicker structures. The structures display comparably small differences between the different drying protocols despite the quite different drying conditions.
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| 12. |
- Bayod, Elena, et al.
(författare)
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Low shear rheology of concentrated tomato products. Effect of particle size and time
- 2007
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Ingår i: Food Biophysics. - : Springer Science and Business Media LLC. - 1557-1866 .- 1557-1858. ; 2:4, s. 146-157
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Tidskriftsartikel (refereegranskat)abstract
- Time-dependent rheological properties of three tomato paste suspensions in the concentration range of 200-1,000 g paste/kg suspension have been investigated by using the vane geometry at shear rates gamma < 10 s(-1). Creep tests were conducted to analyze the influence of the level of stress on the rheological behavior of the samples before and after homogenization. The experimental results indicate that the suspensions exhibit an elastic behavior at long times and relatively low stresses, which proves that this type of material can be characterized by a yield stress (sigma(y)). Applying stresses just beyond the yield stress, an initial rheopectic behavior appeared. This increase in viscosity at low deformations was markedly larger after homogenization, and this difference was attributed to changes in the aspect ratio, shape, and orientation of the particles induced by homogenization. These structural changes were also reflected in the transient viscosity when the samples were subjected to larger stresses (sigma >>sigma y): before homogenization the suspensions exhibited a steady-state viscosity at large deformations, whereas after homogenization, the transient viscosity continuously decreased. That behavior was attributed to flocculation of the particles.
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| 13. |
- Börjesson, Erik, et al.
(författare)
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Entrapment of air during imbibition of agglomerated powder beds
- 2017
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Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774. ; 201, s. 26-35
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Tidskriftsartikel (refereegranskat)abstract
- Complete wetting is crucial for efficient recombination of powders. On the powder bed scale, wetting is governed solely by capillary forces and the resistance to flow, i.e. spontaneous imbibition. Slow or incomplete imbibition of the powder bed may lead to gelling of the liquid front, which will stop the recombination process and cause the formation of lumps, which is usually undesirable. In this study, the spontaneous imbibition of powder beds consisting of spray-dried dairy powders with diverse morphologies has been investigated. Uniform radial spreading of the imbibition front was seen in all the beds, but a large amount of air was trapped in the inter-particle free space in the imbibed volume. A positive correlation was found between bed porosity and the fraction of air trapped in the bed after imbibition. Since the amount of trapped air was calculated as a fraction of the porosity of the dry bed, this relation was unexpected. The large fraction of air trapped in the bed and the uniform radial spreading of the imbibition front indicate considerable heterogeneity of bed on the microscopic scale, but a homogenous structure on the macroscopic scale. Possible explanations of the large fraction of trapped air are the presence of local dead-end structures in the bed and film flow of the imbibing liquid.
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| 14. |
- Börjesson, Erik, et al.
(författare)
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Evaluation of particle measures relevant for powder bed porosity-A study of spray dried dairy powders
- 2014
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910. ; 253, s. 453-463
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Tidskriftsartikel (refereegranskat)abstract
- The formation of lumps during large scale wetting of spray dried powders is a common problem in the industry. The result is a large energy demand if an efficient mixing is to be achieved at the industrial scale. If more knowledge regarding the phenomena governing lump formation is obtained, the unit operation could be optimized and made more efficient. As a part of increasing the understanding of lump formation, the wetting of the porous media that is a powder bed needs to be understood. This wetting relates to the structure and void space (porosity) of the powder bed, which is why a relation between powder bed porosity and readily obtainable powder particle morphology parameters is sought. In this study a thorough investigation of the morphology of five different spray dried milk powders, with arbitrary particle shapes, was performed using manual image analysis of scanning electron microscope (SEM) images as well as automated methods based on light scattering and projected image analysis. The results of the automated methods, when utilized on the complexly shaped samples, were validated by a comparison to the SEM image analysis. This enabled the development of a relation between powder morphology and powder bed porosity based on data from automated methods. The results indicate that automated methods based on light scattering underestimate the particle sizes of arbitrary shaped particles. Methods based on projected image analysis, however, show a better agreement with SEM image analysis. The developed relation between powder bed porosity and powder particle morphology is based on defining the bed as having either an "Agglomerates in fines", "Bicontinuous" or "Fines in agglomerates" structure. The structure of each powder is determined based on calculation of a "BedRatio" which is a function of the phi(agglomerate) and phi(fines) both shown to be readily obtainable by automated methods. The calculated porosities of the powders investigated in this study show a good agreement with experimental measurements and are considered to correspond well to earlier literature. It is, however, clear from the a experiments that care needs to be taken during bulk density measurement of spray dried powders so that no intra particle void space is taken into consideration in the calculations. (C) 2013 Elsevier B.V. All rights reserved.
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| 15. |
- Börjesson, Erik, et al.
(författare)
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Permeability of powder beds formed from spray dried dairy powders in relation to morphology data
- 2016
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910. ; 298, s. 9-20
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Tidskriftsartikel (refereegranskat)abstract
- The formation of lumps during industrial recombination of powder is a common problem in many industries. An important step in the recombination process is the wetting of the dry material. Only with an efficient wetting the individual powder particles will disperse and a complete dissolution will occur. In difference, a slow or incomplete wetting will not supply liquid to all portions of the powder, resulting in the formation of lumps.The resistance to wetting can be described by a material's permeability. This parameter is often estimated using the Kozeny-Carman equation, which models the permeability of a porous medium (such as a bed of powder) based on the porosity and specific surface area of the medium. This model has proven valid for a bed of packed spheres, but due to the model assumptions the accuracy of the model when utilized on beds formed from more complex, spray dried powders can be questioned.In this study, the permeability of powder beds consisting of spray-dried diary powders when exposed to an air flux has been characterized, using a method based on air permeametry. The results show that the Kozeny-Carman model is insufficient to estimate the permeability of such beds. Furthermore, the measured porosity of the bed had no influence on the permeability constant.Based on the results of this study a correlation between morphological powder parameters and permeability was developed. This correlation indicates that a small surface weighted average diameter of the particles as well as a narrow width of the particle size distribution have a positive effect on the permeability of a bed. In addition, incorporation of the structural parameter "BedRatio", defining the basis of the bed to consist of agglomerates or primary particles (fines), indicates that a bed consisting of mainly agglomerates has a slightly larger permeability.
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| 16. |
- Börjesson, Erik, et al.
(författare)
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The dissolution behavior of individual powder particles
- 2013
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Ingår i: Dairy Science & Technology. - : Springer Science and Business Media LLC. - 1958-5586 .- 1958-5594. ; 93:4-5, s. 357-371
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Tidskriftsartikel (refereegranskat)abstract
- The formation of lumps is a common problem during powder reconstitution in food industry. If more knowledge regarding the phenomena controlling the process could be obtained, the process of industrial powder recombination could be optimized. This demands investigation of the process at three different levels: the scale of individual powder particles, the scale of powder beds, and the scale of industrial recombination. If knowledge from all three scales could be combined, a model of the entire process could be constructed. In this study, we present a new flow-cell-based method for investigating the dissolution rate of individual powder particles in controlled liquid flow. The flow cell allows for alteration of the flow velocity and only subjects the investigated powder particles to mild stress before the analysis. The dissolution process in the cell is recorded, and data are obtained by image analysis. Sodium caseinate has been used as a model substance in these experiments. The results show that the particle dissolution rate is a function of the flow velocity of the liquid, and the results correspond to earlier established methods. The investigation of individual particles shows a variation in dissolution rate between particles resulting from the diverse particle morphology from an industrial batch of powder. The results indicate that the dissolution interface concentration of dissolving sodium caseinate particles corresponds well to the overlap concentration of the specie.
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| 17. |
- Castro, Alejandra, et al.
(författare)
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Dietary fiber, fructooligosaccharides, and physicochemical properties of homogenized aqueous suspensions of yacon (Smallanthus sonchifolius)
- 2013
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Ingår i: Food Research International. - : Elsevier BV. - 0963-9969. ; 50:1, s. 392-400
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Tidskriftsartikel (refereegranskat)abstract
- Yacon roots are a promising source of inulintype fructans (35 g/100 g dry matter) with a total amount of dietary fiber of about 45 g/100 g dry matter. The polydispersity of the particle size distribution of yacon aqueous suspension was reduced with increasing the degree of homogenization due to two phenomena: aggregation of particles, and disruption of large particles. Nonhomogenized yacon suspensions exhibited large cell clusters that were disrupted into small cell clusters, single cells, and aggregates. The most concentrated suspension exhibited mainly aggregates. The reducing effect of homogenization and the absence of a concentration effect on volume fraction were attributed to the dense packing of small particles and aggregates in between large particles thus allowing the water within the structure to be released. Yacon suspensions exhibited high elastic modulus (750 Pa) at low water insoluble solids content (0.9 % WIS). The results suggested that inulintype fructans contributed to the elastic properties of yacon suspensions. Yacon suspensions exhibited brittle flow behavior and they can be considered as semiconcentrated i.e. the yacon suspensions studied in this work represented a region immediately after the transition region where the rheological properties of yacon suspensions are dependent on concentration, particle interaction, and particle properties. Particle interactions seem to be of great importance as the elastic modulus (G’) reached 750 Pa at low water insoluble solids content (<1%).
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| 18. |
- Castro, Alejandra, et al.
(författare)
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Effect of heat tretment and homogenization on the rheological properties of aqueous parsnip suspensions
- 2013
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Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774. ; 117:3, s. 383-392
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Tidskriftsartikel (refereegranskat)abstract
- Parsnip (Pastinaca sativa) suspensions, at concentrations corresponding to a dilute and concentrated regime, were subjected to pasteurization, and heat treatments that favored beta-elimination reactions and pectin methyl esterase activity. The different heat treatments were combined with homogenization. Physicochemical properties such as content of insoluble/soluble material and insoluble/soluble pectin were measured together with particle and rheological properties. Pectin methyl esterase activity led to a high yield of insoluble material and insoluble pectin, whereas beta-elimination led to a high yield of soluble material and solubilized pectin. Homogenization after heat treatment resulted in increased solubilization of the pectin, especially after beta-elimination reactions. Parsnip suspensions subjected to pectin methyl esterase activity exhibited the highest elastic modulus most likely due to the cross-linked pectin conferring rigidity to the cell walls. The content of insoluble material and the particle properties such as size and rigidity are important factor for the rheological properties of concentrated parsnip suspensions.
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| 19. |
- Castro, Alejandra, et al.
(författare)
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Parsnip (Pastinaca sativa L.): Dietary fibre composition and physicochemical characterization of its homogenized suspensions
- 2012
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Ingår i: Food Research International. - : Elsevier BV. - 0963-9969. ; 48:2, s. 598-608
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Tidskriftsartikel (refereegranskat)abstract
- The dietary fibre composition in parsnip has been determined in the soluble and insoluble fraction, together with the physicochemical properties (morphology of particles, particle size distribution (PSD), volume fraction and rheological properties) of the parsnip suspensions at different paste concentration and degree of homogenization. The content of dietary fibre in parsnip was 30.4% of the dry matter, composed mainly by neutral sugars (18.4%), pectic substances (10.10%) and Klason lignin (1.92%). Homogenization affected the particle size distribution of parsnip suspension (p<0.001). resulting in smaller cell-clusters. By increasing the degree of homogenization, the area based diameter of large particles (d(32L)) and the volume percentage of large particles (vol(L)%) decreased, whereas the volume percentage of small particles (vol(S)%) increased. Concentration affected the rheological properties of parsnip suspensions (p<0.001). The volume fraction (phi) increased with paste concentration but was reduced with homogenization. By plotting the elastic modulus, G', as a function of volume fraction, phi, we showed the existence of a diluted and concentrated regime with a transition region at approximately phi = 19% for parsnip suspensions. Above the transition region, concentration of particles played an important role for the rheological properties. Based on the results achieved in this investigation we suggest that the gel network is mainly formed by the large particles, e.g. >100 mu m, and the smaller are preferably in the voids between the larger ones. (C) 2012 Elsevier Ltd. All rights reserved.
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| 20. |
- Castro-Alba, Vanesa, et al.
(författare)
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Effect of fermentation and dry roasting on the nutritional quality and sensory attributes of quinoa
- 2019
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Ingår i: Food Science and Nutrition. - : Wiley. - 2048-7177. ; 7:12, s. 3902-3911
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundQuinoa is a pseudocereal with relatively high content of proteins and minerals that also contains mineral inhibitors such as phytate. The aim of the present study was to evaluate lactic acid fermentation and dry roasting on the nutritional quality and sensory attributes of quinoa. Various processes were evaluated, and quinoa grains were dry-roasted, milled, and fermented, either with or without the addition of wheat phytase or activated quinoa phytase (added as back-slop starter), for 10 hr. In other processes, raw quinoa flour was fermented for 10 hr or 4 hr and dry-roasted. Hedonic sensory evaluation was then performed to evaluate the acceptability of the fermented flours prepared as porridges. ResultsThe combined dry roasting and fermentation processes significantly (p < .05) degraded phytate between 30% and 73% from initial content. The most effective process was fermentation of raw quinoa flour followed by dry roasting, which improved the estimated zinc and iron bioavailability. Particularly, estimated zinc bioavailability improved from low (Phy:Zn 25.4, PhyZn:Ca 295) to moderate (Phy:Zn 7.14, PhyZn:Ca 81.5). Phytate degradation was mainly attributed to the activation of endogenous phytase during fermentation. Dry roasting was effective in improving the sensory attributes of the fermented quinoa flour. Porridge made with raw quinoa flour fermented for 4 hr and dry-roasted was more favorable to overall acceptability than that which was fermented for 10 hr and dry-roasted. ConclusionFermentation of quinoa flour for 4 hr followed by dry roasting was successful in improving both nutritional and sensory attributes of the final product.
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| 21. |
- Castro-Alba, Vanesa, et al.
(författare)
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Fermentation of pseudocereals quinoa, canihua, and amaranth to improve mineral accessibility through degradation of phytate
- 2019
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Ingår i: Journal of the Science of Food and Agriculture. - : Wiley. - 1097-0010 .- 0022-5142. ; 99:11, s. 5239-5248
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Pseudocereals are nutrient-rich grains with high mineral content but also phytate content. Phytate is a mineral absorption inhibitor. The study's aim was to evaluate phytate degradation during spontaneous fermentation and during Lactobacillus plantarum 299v® fermentation of quinoa, canihua, and amaranth grains and flours. It also aimed to evaluate the accessibility of iron, zinc, and calcium and to estimate their bioavailability before and after the fermentation of flours with starter culture. Lactic acid, pH, phytate, and mineral content were analyzed during fermentation. RESULTS: Higher phytate degradation was found during the fermentation of flours (64–93%) than during that of grains (12–51%). Results suggest that phytate degradation was mainly due to endogenous phytase activity in different pseudocereals rather than the phytase produced by added microorganisms. The addition of Lactobacillus plantarum 299v® resulted in a higher level of lactic acid (76.8–82.4 g kg−1 DM) during fermentation, and a relatively quicker reduction in pH to 4 than in spontaneous fermentation. Mineral accessibility was increased (1.7–4.6-fold) and phytate : mineral molar ratios were reduced (1.5–4.2-fold) in agreement with phytate degradation (1.8–4.2-fold) in fermented flours. The reduced molar ratios were still above the threshold value for the improved estimated mineral bioavailability of mainly iron. CONCLUSION: Fermentation proved to be effective for degrading phytate in pseudocereal flours, but less so in grains. Fermentation with Lactobacillus plantarum 299v® improved mineral accessibility and estimated bioavailability in flours. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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| 22. |
- Castro-Alba, Vanesa, et al.
(författare)
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Phytate, iron, zinc, and calcium content of common Bolivian foods and their estimated mineral bioavailability
- 2019
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Ingår i: Food Science and Nutrition. - : Wiley. - 2048-7177. ; 7:9, s. 2854-2865
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Tidskriftsartikel (refereegranskat)abstract
- There is a scarcity of information on mineral and phytate content in plant-based foods in Bolivia. This study aimed to analyze iron, zinc, calcium, and phytate content and estimate the mineral bioavailability of foods consumed in Chapare, Bolivia. Minerals and phytate were analyzed, and bioavailability was estimated in 17 food samples. Leafy vegetables and green legumes had the highest mineral content, followed by pseudocereals. Estimated mineral bioavailability was low for cereals, dry legumes, pseudocereals, and flaxseeds foods mainly due to phytate content. But estimated zinc bioavailability for black cornmeal, yellow corn, and dry peas was moderate. Strong correlations (p < 0.01) were found between the three minerals, while phytate correlated negatively to iron, zinc, and calcium. To get an overview of the estimated mineral bioavailability of plant-based diets, we have included foods, from the same area, analyzed in a previous study where the evaluated diet covers 80% of RNI for iron and zinc, but <40% of calcium. In conclusion, leafy vegetables and green legumes had the highest contents of minerals and the lowest phytate content of the foods analyzed in the study. The usage of processing strategies and dietary diversification to reduce phytate content would significantly improve estimated mineral bioavailability in plant-based diets.
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| 23. |
- Chambal, Borges, et al.
(författare)
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Edible proteins from coconut milk press cake; one step alkaline extraction and characterization by electrophoresis and mass spectrometry
- 2012
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Ingår i: Food Research International. - : Elsevier BV. - 0963-9969. ; 47:2, s. 146-151
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Tidskriftsartikel (refereegranskat)abstract
- Coconut milk press cake, the spent endosperm left over after the extraction of coconut milk, was utilized to extract additional protein under alkaline conditions. The maximum protein yield was observed at 50 degrees C and pH 11 and corresponded to total endosperm protein yield of 71%, favourably comparable to yields of more complex extractions. The extract was characterized by amino acid analysis and 1D SDS-PAGE, 2D electrophoresis and MS MS spectroscopy. Coconut milk and insoluble milk sediment from the same individual nuts were also analyzed. The alkaline extract reproducibly differed from the other fractions and from those reported by others in amino acid content as seen in Principal Component Analysis, and had in particular higher threonine content The peptide found in the alkaline extract but with no counterpart in coconut milk or its sediment showed IP (approximate to 5) and mass (approximate to 40 kDa) and matched partially glutelin from oil palm. (c) 2011 Elsevier Ltd. All rights reserved.
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| 24. |
- Chambale, Borges, et al.
(författare)
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Coconut Press Cake Alkaline Extract—Protein Solubility and Emulsification Properties
- 2013
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Ingår i: Food and Nutrition Sciences. - 2157-9458. ; 4:9B, s. 29-37
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Tidskriftsartikel (refereegranskat)abstract
- The solubility and the emulsification properties of a crude freeze dried alkaline protein extract (APE), 30% protein, obtained from coconut milk press cake by one step extraction at pH 11, were characterized at pH 2 to 11, and the cream and subnatant fractions of the emulsion studied by SDS-PAGE electrophoresis. The protein solubility followed U profile, showing a minimum at pH 3 to 4, close to but not identical to reported iso-electric points of 4 - 5 for many coconut protein fractions. The extract showed good capacity to form oil-in-water emulsion outside the low solubility pH range. The bands that appeared to play a role in the emulsification were found at 32 and 42 kDa in SDS-PAGE electrophoresis, but the most predominant absorbed band was at 23 kDa.
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| 25. |
- Chambale, Borges, et al.
(författare)
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Heat Induced Gels from Coconut Press Cake Proteins
- 2014
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Ingår i: Food and Nutrition Sciences. - : Scientific Research Publishing, Inc.. - 2157-9458 .- 2157-944X. ; 5:6, s. 562-570
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Tidskriftsartikel (refereegranskat)abstract
- Freeze-dried coconut press cake powder (CPP), 43% w/w protein, was used to investigate the heat-induced gelation by heating in rheometer to 75℃ in a wide range of pH values, from 4 to 9. Low strain oscillatory method applied the measure visco-elastic propertieson 15% w/w CPP. The gel strength was also assessed by a texture analyzer. SDS-PAGE electrophoresis was conducted to identify the proteins evolved in the gel network structure and the gel micro-structure was also evaluated. At low pH, the CPP proteins formed soft (elastic modulus <100 Pa) particulate gels prone to syneresis, with aggregate size of the order of 4.2 micrometers. In the alkaline region, homogenous gels were induced by heating. Gel strength started to increase dramatically from 64℃ to 67℃, for pH 9 and pH 8 respectively, reaching the maximum gel elastic modulus over 1000 Pa at pH 9. The SDS-PAGE showed that the polypeptide sub-unities at 24, 32 - 34 and 53 kDa were the most prominent in gelation.
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| 26. |
- Chiau, Eulália, et al.
(författare)
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Softening of dried Vangueria infausta (African medlar) using maltodextrin and sucrose
- 2013
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Ingår i: African Journal of Food Science. - 1996-0794. ; 7:10, s. 382-391
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Tidskriftsartikel (refereegranskat)abstract
- Softening of dried Vangueria infausta using maltodextrin and sucrose was investigated experimentally. The pulp of V. infausta was dried in a convective dryer, the influence of drying temperature as well as relationship between water content and water activity were examined. In this study, 48 samples of V. infausta pulp, with and without maltodextrin or sucrose, were dried at air temperatures of 60 and 80°C, at a constant air velocity of 3 m/s, for 0-240 min, and until constant weight. The water content, water activity, hardness and toughness were evaluated throughout the drying process. Samples dried at 80°C exhibited shorter drying times than samples dried at 60°C. The water activity of fruit dried for 240 min at 80°C varied from 0.633 to 0.759, and the fruit was thus safe regarding microbiological spoilage. The hardness and toughness of the dried fruit pulp increased with the reduction in water content, and it was observed that samples of pure pulp became unacceptably hard and tough, when dried to the level needed to obtain microbiological stability. The addition of sucrose as well as maltodextrin has shown to be able to reduce the hardness as well as the toughness of the dried fruit pulp; which can be considered as a strategy to obtain dried fruit pulp with suitable consistency.
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| 27. |
- Curi-borda, Cecilia K., et al.
(författare)
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Model for measuring light stability of photolabile substances in powder beds using spray dried bixin microcapsules
- 2021
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Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - : Elsevier BV. - 0927-7757. ; 627
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Tidskriftsartikel (refereegranskat)abstract
- Light stability of different spray dried microencapsulated powders containing the natural colorant bixin was evaluated for 30 days. The encapsulating materials evaluated were sucrose, maltodextrin, and mixtures including gum arabic and pectin as encapsulation enhancers. The photostability of two sets of encapsulated material was compared: one containing purified bixin, and one being an annatto extract composed of bixin and native car-bohydrates. The photodegradation of bixin was monitored by vis-spectroscopy and HPLC. The observed degra-dation was 30–70 times slower compared to unprotected colorants. A model was established for describing the degradation process of the colorant in a solid particle form presented as powder beds. It was concluded that encapsulation in combination with light scattering by the matrix structure had a significant effect on the pro-tection of the colorant. The overall enhancement of bixin stability towards UVA-visible light can be attained by microencapsulation through spray-drying. A correlation was observed between encapsulation efficiency and improved photostability of the colorant.
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| 28. |
- Curi-Borda, Cecilia K, et al.
(författare)
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Multilayer Bixin Microcapsules: The Impact of Native Carbohydrates on the Microencapsulation Efficiency and Dispersion Stability
- 2019
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Ingår i: Foods. - : MDPI AG. - 2304-8158. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- Bixin is a hydrophobic carotenoid present in the integument of the seeds of Bixa orellana. Microencapsulation was applied to obtain water dispersible formulations and protect the colorant against degradation. Microencapsulated systems were obtained by spray-drying a mild alkaline bixin dispersion with different encapsulating materials. The encapsulation trials were performed with and without native carbohydrates of the integument in addition to the main encapsulant. It was possible to dry dispersions with up to 10% bixin counted on total solids. All the studied systems were characterized by colorimetry, UV-vis spectroscopy, Scanning Electron Microscopy, light microscopy, turbidometric sedimentation analyses and laser light diffraction analyses. All the systems showed aqueous dispersibility but displayed differences in their transparency, UV-vis spectra and physical stability at pH 3. The results show that the native carbohydrates enhance the encapsulation efficiency of other encapsulating materials. The chemical composition of this native carbohydrate fraction shows the presence of polysaccharides containing arabinose, galactose and glucose as monomers. Starch was identified enzymatically. The native carbohydrates allowed the encapsulation of bixin in its native microcrystalline form, resulting in a multilayer structure after spray-drying. In addition, the colorant particles displayed dispersibility under acidic aqueous conditions suggesting that they are stabilized by the native carbohydrates after the microcapsules are dissolved.
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| 29. |
- Dahlenborg, Hanna, et al.
(författare)
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Effect of particle size in chocolate shell on oil migration and fat bloom development
- 2015
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Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774 .- 1873-5770. ; 146, s. 172-181
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Tidskriftsartikel (refereegranskat)abstract
- The effects of chocolate shell particle size were investigated by means of its influence on rate of oil migration and fat bloom development. The particle size of the non-fat particles in the chocolate, i.e. sugar and cocoa particles was varied between 15, 22 and 40 mu m. A novel set of analytical techniques was used and by combining migration results with surface topology results clear differences could be observed between the samples. At 23 degrees C storage the samples with a particle size of 15 mu m showed higher rate of oil migration and, further, the earliest development of fat bloom at the surface. This could be observed both macroscopically and microscopically. Thus, it appears as a larger specific surface area of the nonfat particles facilitates migration of filling oil, possibly due to a more heterogeneous and coarser crystal network with higher permeability. Molecular diffusion cannot explain the level of oil migration observed and, thus, convective flow is assumed to be an important contribution in addition to the molecular diffusion. (C) 2014 Elsevier Ltd. All rights reserved.
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| 30. |
- Dahlenborg, Hanna, et al.
(författare)
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Effect of shell microstructure on oil migration and fat bloom development in model pralines
- 2015
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Ingår i: Food Structure. - : Elsevier BV. - 2213-3291. ; 5, s. 51-65
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the influence of shell microstructure on oil migration and fat bloom development in chocolate model systems. The microstructure of the model shells was varied by means of tempering or seeding cocoa butter and the addition of non-fat particles. Further, the impact of different storage conditions was studied. By using a set of novel analytical techniques the migration rate could be connected to the development of fat bloom at the surface. The non-seeded cocoa butter samples showed significantly higher rate of migration together with the highest rate of developed fat bloom, whereas the over-seeded cocoa butter samples showed low migration rate and low rate of fat bloom development. Addition of particles (sugar, cocoa powder and defatted cocoa powder) proved to have a significant impact on the microstructure, since these samples showed a substantially higher rate of migration and fat bloom development compared to seeded cocoa butter samples. Molecular diffusion could not explain the migration behaviour, thus, convective flow is suggested as an important contribution in addition to the molecular diffusion.
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| 31. |
- Dahlenborg, Hanna, et al.
(författare)
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Investigation of Chocolate Surfaces Using Profilometry and Low Vacuum Scanning Electron Microscopy
- 2011
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Ingår i: Journal of the American Oil Chemists Society. - : Wiley. - 0003-021X .- 1558-9331. ; 88:6, s. 773-783
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Tidskriftsartikel (refereegranskat)abstract
- In this study we establish the use of optical non-contact profilometry combined with low vacuum scanning electron microscopy (LV SEM) for the investigation of lipid surfaces. We illustrate, by using profilometry, a methodology for investigation of chocolate surface topology as a function of time, in the same area of interest. Both qualitative and quantitative data analysis has been performed for profilometry data. Further, relating these results to LV SEM images provides complementary topological information and hence a useful toolkit for the study of the chocolate surface prior and post fat bloom formation. For the demonstration of the successful combination of these two analytical techniques, white chocolate pralines were stored at two temperature-controlled conditions (at 18 A degrees C, and cycled between 15 and 25 A degrees C). Surface properties were then investigated during 36 weeks of storage. The surface images and the roughness parameters indicated distinct development of surface characteristics for the two storage conditions. From the results it is suggested that some imperfections, in the form of pores or protrusions, could play a role in fat bloom development and that there may be different main mechanisms of fat migration taking place for the different storage environments. In the present work, a positive correlation of profilometry data to chocolate surface characteristics and early bloom development has been established. There are indications that early prediction of fat bloom can be possible, however further work needs to be done to quantify prediction of fat bloom.
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| 32. |
- Dahlenborg, Hanna, et al.
(författare)
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Study of the porous structure of white chocolate by confocal Raman microscopy
- 2012
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Ingår i: European Journal of Lipid Science and Technology. - : Wiley. - 1438-7697 .- 1438-9312. ; 114:8, s. 919-926
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Tidskriftsartikel (refereegranskat)abstract
- Confocal Raman microscopy has been shown to be a useful technique for investigation of white chocolate surfaces. The appearance of protrusions and pores, and the distribution of fat, sucrose, and milk powder at and below the surface of white chocolate pralines were investigated using confocal Raman microscopy. Raman horizontal and depth scans showed that the protrusions and pores continue at least 10 mu m into the chocolate shell and that some protrusions and channels mainly consist of fat, while some consisted of a fat layer, leaving a hollow space underneath. Further, the pores and their continuing channels consisted of nothing but air. These findings indicate that the protrusions might be connected to channels where we suggest a pressure driven convective flow of liquid fat from within the chocolate matrix that, depending on temperature, moves up to the surface or goes back into the matrix, leaving an empty pore with a shell of fat at the surface, which in some cases collapse and leaves a hollow pore and channel. Therefore, these findings support that the protrusions could be connected to oil migration in chocolate and, thus, further to fat bloom development. Practical applications: Confocal Raman microscopy can be used to investigate the local distribution of different components in white chocolate. This technique offers the possibility to acquire the local distribution of different components within the sample, with a resolution down to the optical diffraction limit. Further, the analysis can be performed at ambient conditions, without requiring any special sample preparation or marker molecules. The results obtained by using this technique suggest that specific surface imperfections on chocolate could be part of a network of pore structures at and beneath the chocolate surface, which could be related to oil migration and thus, to fat bloom formation.
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| 33. |
- Eliasson, Ann-Charlotte, et al.
(författare)
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From Molecules to Products: Some Aspects of Structure-Function Relationships in Cereal Starches
- 2013
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Ingår i: Cereal Chemistry. - 0009-0352. ; 90:4, s. 326-334
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Tidskriftsartikel (refereegranskat)abstract
- In this review, starch behavior is described from molecules in solution to the use of starch in products. The determination of molecular characteristics with asymmetrical flow field-flow fractionation is described, and the behavior of starch in binary solutions is discussed. The organization of starch in granules and the changes in organization during gelatinization and retrogradation are then described. The role of starch retrogradation in bread staling is described in some detail, and the influence of water mobility and distribution is discussed in relation to amylopectin retrogradation. Finally, the use of starch as emulsifier is described. Hydrophobically modified starch is one possibility for emulsion stabilization; also, the starch granule as such can be used to stabilize emulsions (so-called Pickering emulsions).
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| 34. |
- Fatouros, Dimitrios G., et al.
(författare)
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Colloidal Structures in Media Simulating Intestinal Fed State Conditions with and Without Lipolysis Products
- 2009
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Ingår i: Pharmaceutical Research. - : Springer Science and Business Media LLC. - 1573-904X .- 0724-8741. ; 26:2, s. 361-374
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Tidskriftsartikel (refereegranskat)abstract
- Purpose. To study the ultrastructure of biorelevant media and digestion products of self-nanoemulsifying drug delivery system (SNEDDS) at high level BS/PL conditions. Methods. Cryogenic transmission electron microscopy (Cryo-TEM) was employed to visualize the colloid structures in the biorelevant media and lipolytic products generated during hydrolysis of a SNEDDS formulation. Their electrical properties were investigated by measuring their zeta-potential values. Results. In the biorelevant media, vesicles (either unilamellar or multilamellar) and bilayer fragments are visualized. Occasionally, vesicles with an internal deformed structure are recognized, suggesting surface tension or uneven lateral stress. Visualization studies of the intermediate colloidal phases produced during digestion of a SNEDDS using the in vitro lipolysis model revealed the formation of similar structures as previously reported. The zeta-potential of the media was negatively charged and decreased from -23 to -35 mV with increasing surfactant/lipid load. Lower zeta-potential values (-16 mV) obtained for the structures formed during the lipid hydrolysis of the SNEDDS were probably due to the presence of calcium, which shields the surface, thereby reducing the charge. Conclusions. The diversity of these vesicles in terms of size, lamellarity, and internal organization advocate their important role during lipid digestion in the gastrointestinal milieu.
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| 35. |
- Fatouros, Dimitrios G., et al.
(författare)
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Morphological observations on a lipid-based drug delivery system during in vitro digestion
- 2007
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 1879-0720 .- 0928-0987. ; 31:2, s. 85-94
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Tidskriftsartikel (refereegranskat)abstract
- The in vitro digestion of a self nano-emulsifying drug delivery system (SNEDDS) was visualized by cryogenic transmission electron microscopy (Cryo-TEM). The dynamic lipolysis model, simulating the environment of the gastrointestinal tract in fasted conditions, was used for this purpose. The results revealed that micelles are present during the entire lipolysis process. Oil droplets from the self nano-emulsifying drug delivery system are transformed to spherical or elongated unilamellar vesicles as lipolysis progresses. Low numbers of bilamellar and open vesicles were detected. After 50% hydrolysis a decrease in the number of unilamellar vesicles and oil droplets was observed. Furthermore, the electrical properties of the oil droplets were investigated by measuring their C-potential values as a function of time. An increase (in absolute values) to the zeta-potential of the hydrolyzing SNEDDS droplets observed versus time implying (binding or incorporation) of the micelles to the surface. The current data emphasize that Cryo-TEM combined with the in vitro dynamic lipolysis model can offer useful information on the formation of the various colloid phases during in vitro digestion of lipid-based formulations. Furthermore, it can provide a better understanding of the in vivo behavior of these systems, as well the solubilization of lipophilic drug compounds, offering new insights for designing and optimizing oral lipid-based formulations and possibly predicting their in vivo behavior. Such methodology can be a useful tool for the strategic development of lipid-based formulations. (c) 2007 Elsevier B.V. All rights reserved.
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| 36. |
- Fatouros, D. G., et al.
(författare)
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Physicochemical Characterization of Simulated Intestinal Fed-State Fluids Containing Lyso-Phosphatidylcholine and Cholesterol
- 2009
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Ingår i: Dissolution Technologies. - 1521-298X. ; 16:3, s. 47-50
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Tidskriftsartikel (refereegranskat)abstract
- An array of simulated intestinal fed-state fluids, where phosphatidylcholine (PC) was replaced by lysophosphatidylcholine (LPC) and cholesterol (Chol) was added, were visualized with Cryogenic Transmission Electron Microscopy (Cryo-TEM). Micelles were the dominating structural features, emphasizing the micellar-forming characteristics of LPC. Upon increase of the monoglyceride (MG) level, unilamellar vesicles and multivesicular structures were formed. These findings suggest the solubilization of poorly soluble drugs might be affected by the intermediate colloidal phases produced in the gastrointestinal tract.
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| 37. |
- Fatouros, Dimitrios G., et al.
(författare)
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Structural development of self nano emulsifying drug delivery systems (SNEDDS) during In vitro lipid digestion monitored by small-angle x-ray scattering
- 2007
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Ingår i: Pharmaceutical Research. - : Springer Science and Business Media LLC. - 1573-904X .- 0724-8741. ; 24:10, s. 1844-1853
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Tidskriftsartikel (refereegranskat)abstract
- Purpose. To investigate the structural development of the colloid phases generated during lipolysis of a lipid-based formulation in an in vitro lipolysis model, which simulates digestion in the small intestine. Materials and Methods. Small-Angle X-Ray scattering (SAXS) coupled with the in vitro lipolysis model which accurately reproduces the solubilizing environment in the gastrointestinal tract and simulates gastrointestinal lipid digestion through the use of bile and pancreatic extracts. The combined method was used to follow the intermediate digestion products of a self nano emulsified drug delivery system (SNEDDS) under fasted conditions. SNEDDS is developed to facilitate the uptake of poorly soluble drugs. Results. The data revealed that a lamellar phase forms immediately after initiation of lipolysis, whereas a hexagonal phase is formed after 60 min. The change of the relative amounts of these phases clearly demonstrates that lipolysis is a dynamic process. The formation of these phases is driven by the lipase which continuously hydrolyzes triglycerides from the oil-cores of the nanoemulsion droplets into mono- and diglycerides and fatty acids. We propose that this change of the over-all composition of the intestinal fluid with increased fraction of hydrolyzed nanoemulsion induces a change in the composition and effective critical packing parameter of the amphiphilic molecules, which determines the phase behavior of the system. Control experiments (only the digestion medium) or the surfactant (Cremophor RH 40) revealed the formation of a lamellar phase demonstrating that the hexagonal phase is due to the hydrolysis of the SNEDDS formulation. Conclusion. The current results demonstrate that SAXS measurements combined with the in vitro dynamic lipolysis model may be used to elucidate the processes encountered during the digestion of lipid-based formulations of poorly soluble drugs for oral drug delivery. Thus the combined methods may act as an efficient screening tool.
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| 38. |
- Fuentes, Catalina, et al.
(författare)
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Physicochemical and structural properties of starch from five Andean crops grown in Bolivia
- 2019
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier BV. - 0141-8130. ; 125, s. 829-838
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Tidskriftsartikel (refereegranskat)abstract
- Three Andean grains - amaranth (Amaranthus caudatus), quinoa (Chenopodium quinoa), canihua (Chenopodium pallidicaulle) - and two Andean roots starches - achira (Canna indica), maca (Lepidium meyenii) - were studied. Physicochemical properties such as granule size, crystallinity, pasting properties among other as well as structural properties such as root-mean-square radius (rrms), weight-average molar mass (Mw) and apparent density (ρapp) were analyzed in order to evaluate the relation between them. Grains were similar in most of their characteristics as roots in their i.e. granule size, shape, type of crystallinity, Mw and rrms varied according to botanical source. The starch granules from grains were in a narrow diameter range (0.5 to 2 μm) and displayed A-type X-ray diffraction pattern (XRD). Roots starch had a wide granule diameter range (1 to 100 μm) and displayed a B-type XRD. The amylose content varied between 0 and 48% where amaranth had the lowest value and achira had the highest. Furthermore, quinoa and canihua starches had very low breakdown in pasting properties, indicating high stability during cooking. A model is proposed that relates pasting properties i.e. peak viscosity and final viscosity with ρapp, gelatinization enthalpy, granule size and amylose content.
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| 39. |
- Glicerina, Virginia, et al.
(författare)
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The Influence of Different Processing Stages on Particle Size, Microstructure, and Appearance of Dark Chocolate
- 2014
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Ingår i: Journal of Food Science. - : Wiley. - 0022-1147. ; 79:7, s. 1359-1365
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Tidskriftsartikel (refereegranskat)abstract
- The effect of different process stages on microstructural and visual properties of dark chocolate was studied. Samples were obtained at each phase of the manufacture process: mixing, prerefining, refining, conching, and tempering. A laser light diffraction technique and environmental scanning electron microscopy (ESEM) were used to study the particle size distribution (PSD) and to analyze modifications in the network structure. Moreover, colorimetric analyses (L*, h degrees, and C*) were performed on all samples. Each stage influenced in stronger way the microstructural characteristic of products and above all the PSD. Sauter diameter (D [3.2]) decreased from 5.44 mu m of mixed chocolate sample to 3.83 mu m, of the refined one. ESEM analysis also revealed wide variations in the network structure of samples during the process, with an increase of the aggregation and contact point between particles from mixing to refining stage. Samples obtained from the conching and tempering were characterized by small PS, and a less dense aggregate structure. From color results, samples with the finest particles, having larger specific surface area and the smallest diameter, appeared lighter and more saturated than those with coarse particles.
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| 40. |
- Hellborg, D., et al.
(författare)
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A method for measuring the imbibation rate of powder in a liquid
- 2010
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Ingår i: Chemical Engineering and Processing. - : Elsevier BV. - 0255-2701. ; 49:6, s. 599-604
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Tidskriftsartikel (refereegranskat)abstract
- Mixing of powders into liquids is a common unit operation. Mixing can be divided into several steps: imbibation of the powder into the liquid being the first Under some circumstances, for instance, if the powder has poor wetting properties, imbibation can be the rate-determining step. In this study imbibation in a commercial mixer was studied and a method to measure powder imbibation in a model that simulates the commercial mixer was developed. The imbibation mechanism in the commercial mixer is based on a wave drawing the powder down into the liquid, and surface flow transporting it towards the wave A wave imbibation model was constructed based on the same mechanisms, in which physical parameters such as wave height, surface velocity and surface residence time could be varied. An experimental procedure was used to determine the maximum imbibation rate Measurements were found to have good reproducibility, with a standard error of means of 4.7% for spray-dried sodium caseinate The maximum imbibation rates were found to be of the same magnitude in the commercial mixer and the wave imbibation model: 0.04 kg/s m in the commercial mixer and 0 06-0.16 kg/s m in the wave imbibation model for spray-dried sodium caseinate powder. (C) 2010 Elsevier B V. All rights reserved
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| 41. |
- Hellborg, David, et al.
(författare)
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The influence of powder properties on the imbibation rate
- 2012
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Ingår i: Colloids and Surfaces B: Biointerfaces. - : Elsevier BV. - 1873-4367 .- 0927-7765. ; 93, s. 108-115
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Tidskriftsartikel (refereegranskat)abstract
- Mixing of powders into liquids is a common unit operation. Mixing can be divided into several steps, imbibation of the powder into the liquid being the first. Under some circumstances, such as when the powder has poor wetting properties, imbibation can be the rate-determining step. The effects of different powder properties on the imbibation rate were evaluated using an experimental imbibation model based on the imbibing process employed in an industrial powder-in-liquid mixer. A multivariate analysis of the results suggests that bulk density and capillary penetration rate, and to some extent cohesivity, play an important role in determining the powder imbibation rate. The results also suggest that the capillary penetration rate is increasing on a large particle radius, slow solubilisation of the particles and a low ability of the particles to generate viscosity.
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| 42. |
- Håkansson, Andreas, et al.
(författare)
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A high-pressure homogenization emulsification model : improved emulsifier transport and hydrodynamic coupling
- 2013
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Ingår i: Chemical Engineering Science. - 0009-2509 .- 1873-4405. ; 91, s. 44-53
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Tidskriftsartikel (refereegranskat)abstract
- The high-pressure homogenizer emulsification modelling framework by Håkansson et al. (2009a, Chemical Engineering Science 64, 2915–2925; 2009b. Food Hydrocolloids 23, 1177–1183), is further developed in this study. The model, including the simultaneous fragmentation of drops, coalescence of drops and kinetic adsorption of macromolecular emulsifiers, is improved with regard to two points. First, the transport of adsorbed emulsifier between drops of different sizes due to the fragmentation and coalescence of drops, is included using bivariate population balances. Second, the coupling of hydrodynamics to the emulsification model is improved using information from recent hydrodynamic investigations. The proposed framework is exemplified using a set of physically reasonable kernels and a production scale high-pressure homogenizer geometry, showing realistic emulsification results.
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| 43. |
- Håkansson, Andreas, et al.
(författare)
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A high-pressure homogenization emulsification model—Improved emulsifier transport and hydrodynamic coupling
- 2013
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Ingår i: Chemical Engineering Science. - : Elsevier BV. - 0009-2509. ; 91, s. 44-53
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Tidskriftsartikel (refereegranskat)abstract
- The high-pressure homogenizer emulsification modelling framework by Håkansson et al. (2009a,Chemical Engineering Science 64, 2915–2925; 2009b. Food Hydrocolloids 23, 1177–1183), is further developed in this study. The model, including the simultaneous fragmentation of drops, coalescence of drops and kinetic adsorption of macromolecular emulsifiers, is improved with regard to two points.First, the transport of adsorbed emulsifier between drops of different sizes due to the fragmentation and coalescence of drops, is included using bivariate population balances. Second, the coupling of hydrodynamics to the emulsification model is improved using information from recent hydrodynamic investigations. The proposed framework is exemplified using a set of physically reasonable kernels and a production scale high-pressure homogenizer geometry, showing realistic emulsification results.
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| 44. |
- Håkansson, Andreas, et al.
(författare)
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A method for estimating effective coalescence rates during emulsification from oil transfer experiments
- 2012
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier. - 0021-9797 .- 1095-7103. ; 374:1, s. 25-33
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Tidskriftsartikel (refereegranskat)abstract
- The Oil Transfer Technique (OTT) was developed by Taisne et al. [1] to measure coalescence during emulsification and has been applied since in several studies. One of the main drawbacks of this technique is that it only gives a qualitative measure of coalescence. This paper proposes a new evaluation method of OTT experimental results for estimating qualitative coalescence rates, e.g. for investigating the scaling of coalescence with emulsification parameters (such as homogenizing pressure, and emulsifier concentration).The method is based on comparison with simulated OTT experiments using bivariate Population Balance Equation models. Simulations have been performed under a wide variety of conditions in order to investigate the influence of assumptions on coalescence and fragmentation kernels. These investigations show that the scaling of coalescence rates could be determined accurately when the scaling of efficient residence time of drops in the active region of homogenization is known. The proposed evaluation method is also exemplified by analyzing OTT data from two previously published studies.
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| 45. |
- Håkansson, Andreas, et al.
(författare)
-
A method for estimating effective coalescence rates during emulsification from oil transfer experiments.
- 2012
-
Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 1095-7103 .- 0021-9797. ; 374:1, s. 25-33
-
Tidskriftsartikel (refereegranskat)abstract
- The Oil Transfer Technique (OTT) was developed by Taisne et al. [1] to measure coalescence during emulsification and has been applied since in several studies. One of the main drawbacks of this technique is that it only gives a qualitative measure of coalescence. This paper proposes a new evaluation method of OTT experimental results for estimating qualitative coalescence rates, e.g. for investigating the scaling of coalescence with emulsification parameters (such as homogenizing pressure, and emulsifier concentration). The method is based on comparison with simulated OTT experiments using bivariate Population Balance Equation models. Simulations have been performed under a wide variety of conditions in order to investigate the influence of assumptions on coalescence and fragmentation kernels. These investigations show that the scaling of coalescence rates could be determined accurately when the scaling of efficient residence time of drops in the active region of homogenization is known. The proposed evaluation method is also exemplified by analyzing OTT data from two previously published studies.
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| 46. |
- Håkansson, Andreas, et al.
(författare)
-
Dynamic simulation of emulsion formation in a high pressure homogenizer
- 2009
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Ingår i: Chemical Engineering Science. - : Elsevier BV. - 0009-2509. ; 64:12, s. 2915-2925
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Tidskriftsartikel (refereegranskat)abstract
- A simulation model for emulsification in High Pressure Homogenization (HPH), based on a population balance approach, is developed assuming it to be controlled by three simultaneous processes; fragmentation, coalescence and adsorption of a macromolecular emulsifier. The aim is to investigate the implications of adding a set of models together; studying the effects of dynamics, size effects and process interactions. For fragmentation; turbulent inertial and turbulent viscous forces are included using a dynamic model based on the Weber and Capillary number. It was extended to include a deformation time-scale. The rate of adsorption and coalescence is assumed to be controlled by the collision rate of macromolecular stabilizer and bare interface, modeled using convective and diffusive transport in turbulent flow. By comparing simulation results to general trends found in the literature, it can be concluded that the models can reproduce the general HPH process well. By dividing the active region into discrete steps the dynamic process could also be examined, indicating the homogenization process being composed of three stages with coalescence predominantly found in the last one.
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| 47. |
- Håkansson, Andreas, et al.
(författare)
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Estimation of turbulent fragmenting forces in a high-pressure homogenizer from computational fluid dynamics
- 2012
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Ingår i: Chemical Engineering Science. - : Elsevier BV. - 0009-2509. ; 75, s. 309-317
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to find models for turbulent fragmenting forces in the high-pressure homogeniser from data available in Computational Fluid Dynamics (CFD) simulations with Reynolds Averaged Navier Stokes (RANS) turbulence models. In addition to the more common RANS k-epsilon turbulence models, a Multi-scale k-epsilon model was tested since experimental investigations of the geometry imply large differences in behaviour between turbulent eddies of different length-scales. Empiric models for the driving hydrodynamic factors for turbulent fragmentation using the extra information given by multi-scale simulations were developed. These models are shown to give a more reasonable approximation of local fragmentation than models based on the previously used RANS k-epsilon models when comparing to hydrodynamic measurements in an experimental model. (C) 2012 Elsevier Ltd. All rights reserved.
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| 48. |
- Håkansson, Andreas, et al.
(författare)
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Experimental validation of k–e RANS-CFD on a high-pressure homogenizer valve
- 2012
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Ingår i: Chemical Engineering Science. - 0009-2509 .- 1873-4405. ; 71, s. 264-273
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Tidskriftsartikel (refereegranskat)abstract
- Since the emulsification in the High-Pressure Homogenizer (HPH) is controlled by hydrodynamic forces, the turbulent flow field in the valve region is of significant interest. Computational Fluid Dynamics (CFD) simulations have been used for this in many studies. However, there are reasons to question if the utilized turbulence models, with their inherent assumptions and simplifications, could accurately describe the influential aspects of the flow.This study compares CFD simulations using the methods from previous studies with experimental measurements in a model HPH valve. The results show that the region upstream of the gap can be described accurately regardless of turbulence model and that the gap region can be captured by using one of the more refined k−ε models. None of the studied turbulence models were able to describe the details of the highly turbulent region downstream of the gap. The obtained results are also discussed in relation to generalizability and limitations in using CFD simulations for understanding the emulsification in the HPH.
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| 49. |
- Håkansson, Andreas, et al.
(författare)
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Experimental validation of k–ε RANS-CFD on a high-pressure homogenizer valve
- 2012
-
Ingår i: Chemical Engineering Science. - : Elsevier BV. - 0009-2509. ; 71, s. 264-273
-
Tidskriftsartikel (refereegranskat)abstract
- Since the emulsification in the High-Pressure Homogenizer (HPH) is controlled by hydrodynamic forces, the turbulent flow field in the valve region is of significant interest. Computational Fluid Dynamics (CFD) simulations have been used for this in many studies. However, there are reasons to question if the utilized turbulence models, with their inherent assumptions and simplifications, could accurately describe the influential aspects of the flow. This study compares CFD simulations using the methods from previous studies with experimental measurements in a model HPH valve. The results show that the region upstream of the gap can be described accurately regardless of turbulence model and that the gap region can be captured by using one of the more refined k−ε models. None of the studied turbulence models were able to describe the details of the highly turbulent region downstream of the gap. The obtained results are also discussed in relation to generalizability and limitations in using CFD simulations for understanding the emulsification in the HPH.
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| 50. |
- Håkansson, Andreas, et al.
(författare)
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High resolution experimental measurement of turbulent flow field in a high pressure homogenizer model and its implications on turbulent drop fragmentation
- 2011
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Ingår i: Chemical Engineering Science. - : Elsevier BV. - 0009-2509. ; 66:8, s. 1790-1801
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Tidskriftsartikel (refereegranskat)abstract
- Particle image velocimetry is performed on a model of a high pressure homogenizer, scaled for qualitative similarity of the one phase turbulent flow field in a production scale homogenizer. Flow fields in gap entrance, gap and gap outlet chamber are obtained with high resolution. The measurements show gap flow development and formation of a turbulent wall adherent jet when exiting into the outlet chamber. Turbulent kinetic energy spectra show how the turbulent energy available for fragmentation is transported over distance along the jet centre axis. The high resolution images are also used together with a Kolmogorov-Hinze theory framework for discussing drop fragmentation together with a direct evaluation of disruptive stresses from measurements. For the turbulent inertial mechanism large drops experience high fragmenting force close to eight gap heights downstream of the gap exit where as this occurs closer to 20 gap heights for smaller drops. The turbulent viscous mechanism is most efficient at a downstream distance of eight gap heights into the outlet chamber for all drops sizes. (C) 2011 Elsevier Ltd. All rights reserved.
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