| 1. |
- Aalaei, Kataneh, et al.
(author)
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Storage stability of freeze-dried, spray-dried and drum-dried skim milk powders evaluated by available lysine
- 2016
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In: LWT - Food Science and Technology. - : Elsevier BV. - 0023-6438. ; 73, s. 675-682
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Journal article (peer-reviewed)abstract
- Formation of Maillard products and the influencing factors, which are of crucial importance for both manufacturers and consumers, are still not fully understood. Thus in this study available lysine was used as a marker to monitor the extent of Maillard reactions in freeze-dried, spray-dried and drum-dried skim milk powders during 200 days of storage at highly controlled atmospheres. Storage variables included two temperatures (20 °C, 30 °C) and two relative humidities (33%, 52%). The available lysine in five replicates was quantified at pre-determined intervals by a dye-binding method using Acid-orange 12, validated in our previous work. Findings of this study show that temperature and relative humidity during storage have a profound influence on the rate of available lysine loss. Choice of the drying technology as the other investigated variable also had a significant impact. The drying process least affected the available lysine content in freeze-dried powders, followed by spray-dried and drum-dried powders. Storage at 52% relative humidity and 30 °C for 200 days led to a 39.2–45.9% decrease in the available lysine content, regardless of the drying of skim milk powder, while the powders stored at 33% relative humidity and 20 °C did not show a significant loss during the same period of time.
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| 2. |
- Abdollahi, Mehdi, 1985, et al.
(author)
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Physicochemical and gel-forming properties of protein isolated from salmon, cod and herring by-products using the pH-shift method
- 2019
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In: LWT - Food Science and Technology. - : Elsevier BV. - 1096-1127 .- 0023-6438. ; 101, s. 678-684
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Journal article (peer-reviewed)abstract
- The impacts of variation in fish filleting by-products origin including white muscle (cod), dark muscle (herring) and farmed fish (salmon) on physicochemical and gel-forming properties of protein recovered using the pH-shift method were studied. The effects of different solubilization pHs (acid or alkaline) on protein yield/composition, and its properties were also studied. Alkaline version (pH 11.5–12.5) resulted in maximum protein yield for the three resources which ranked them as: salmon > herring > cod. Increasing solubilization pH from 11.5 to 12.5 increased protein yield in salmon and herring, while maximum protein yield of cod was obtained at pH 12. However, increasing solubilization pH from 11.5 to 12.5 required a two-fold higher amount of alkali compared to the adjustment to 11.5. All recovered proteins had gel-forming capacity; however, cod gels showed higher WHC and breaking force compared with salmon and herring protein gels. Increasing solubilization pH from 11.5 to 12.5 negatively affected the breaking force and color of the salmon and cod protein gels, but improved heme pigment removal, breaking force and whiteness of herring protein gels. The pH-shift process thus showed good potential for recovering high quality protein from the by-products, but protein solubilization pH should be carefully selected based on the target species.
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| 3. |
- Bagon, Bernadette B., et al.
(author)
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Comparative exoproteome analyses of Lactobacillus spp. reveals species-and strain-specific proteins involved in their extracellular interaction and probiotic potential
- 2018
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In: Lebensmittel-Wissenschaft + Technologie. - : Elsevier. - 0023-6438 .- 1096-1127. ; 93, s. 420-426
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Journal article (peer-reviewed)abstract
- Due to their health-promoting effects, the probiotic applications of lactobacilli have been investigated. Aside from their basic cellular functions, the extracellular activities of probiotic lactobacilli influence their establishment and interaction with the host. Many extracellular proteins play important roles in bacterial colonization and survival in their host's gastrointestinal environment. In this study, we compared the exoproteome of three lactobacillus strains isolated from the gastrointestinal tracts of pigs and chickens, namely, Lactobacillus mucosae LM1, L. johnsonii PF01, and L. johnsonii C1–10. Extracellular proteins collected in the mid-logarithmic growth phase were identified and quantified using a Q Exactive™ Orbitrap mass spectrometer (MS). Of 99 total extracellular proteins, 83% belonged to L. mucosae LM1; L. johnsonii PF01 strains had fewer extracellular proteins. Enolase, which is involved in the glycolysis pathway and has moonlighting functions in the adhesion of probiotic bacteria, was found in the core exoproteomes of the three strains. The most abundant proteins of each strain were phosphoketolase in L. mucosae LM1, aggregation-promoting factor in L. johnsonii PF01, and levansucrase in L. johnsonii C1–10. The observed differences between these three exoproteomes in terms of cellular and molecular function elucidate the extracellular activities of these isolates.
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| 4. |
- Berta, M., et al.
(author)
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Effect of viscoelasticity on foam development in zein-starch dough
- 2015
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In: LWT - Food Science and Technology. - : Elsevier BV. - 1096-1127 .- 0023-6438. ; 63:2, s. 1229-1235
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Journal article (peer-reviewed)abstract
- Above the zein glass transition temperature (similar to 40 degrees C), the viscoelasticity of zein-starch dough is similar to that of gluten. This is of interest because this dough might be used to develop gluten-free products, although it has certain limitations such as workability and aging at room temperature. The most effective way to decrease the dough glass transition temperature is to use a plasticizer, which also influences the viscosity. In this study, viscoelastic zein-starch dough samples were prepared with several concentrations of citric acid as the plasticizer, and the effect of viscoelasticity on crumb structure formation during baking was investigated. Extensional viscosity was correlated with the average bubble size after baking. We found that viscosity could be predicted for this system by measuring the shear viscosity, whereby the Trouton ratio was near-constant for the range of plasticizer concentrations investigated. In addition, our dynamic mechanical analysis (DMA) revealed that bubble growth occurs mainly when the dough reaches 100 degrees C, due to a combination of steam formation and thermal softening of the matrix. At higher temperatures, hardening occurs due to drying and zein crosslinking. (C) 2015 Elsevier Ltd. All rights reserved.
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| 5. |
- Dymek, Katarzyna, et al.
(author)
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Effect of pulsed electric field on the germination of barley seeds
- 2012
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In: LWT - Food Science and Technology. - : Elsevier BV. - 0023-6438. ; 47:1, s. 161-166
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Journal article (peer-reviewed)abstract
- This study explores metabolic responses of germinating barley seeds upon the application of pulsed electric fields (PEE). Malting barley seeds were steeped in aerated water for 24 h and PEF-treated at varying voltages (0 (control), 110, 160, 240, 320, 400 and 480 V). The seeds were then allowed to finish germination in saturated air. It is shown that exposure of germinating barley to PEE affects radicle emergence without significantly affecting the seeds gross metabolic activity, as quantified by isothermal calorimetry. An exploration of protein 2-DE profiles of both the embryo and the starchy endosperm showed that, at the studied time scale, no significant changes were found in proteins present at concentrations higher than the detection limit. However, western blotting demonstrated that a-amylase concentration decreases in the PEF-treated seeds. (C) 2011 Elsevier Ltd. All rights reserved.
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| 6. |
- Dymek, Katarzyna, et al.
(author)
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Influence of vacuum impregnation and pulsed electric field on the freezing temperature and ice propagation rates of spinach leaves
- 2015
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In: LWT - Food Science and Technology. - : Elsevier BV. - 0023-6438. ; 64:1, s. 497-502
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Journal article (peer-reviewed)abstract
- Efforts are currently directed towards improving the quality of sensitive tissues of fruits and vegetables after freezing and thawing. One of the methods under investigation is the combination of vacuum impregnation (VI) with cryoprotectants and pulsed electric field (PEF), applied to the plant tissue prior exposure to freezing. The influence of these processes on the freezing temperature and ice propagation rate of spinach baby leaves are here studied. Leaves impregnated with trehalose, sucrose, glucose and mannitol exhibited significantly lower ice propagation rate and higher freezing temperatures in comparison to non-treated controls. Leaves subjected to PEF also showed increased freezing temperatures compared to the non-treated leaves; however the ice propagation rate was not influenced by PEF for the cryoprotectants used in the study, except for leaves impregnated with trehalose, where it was significantly increased and water, where it was significantly decreased. The combination of VI and PEF resulted in comparable freezing temperatures and ice propagation rates as the leaves subjected only to VI. (C) 2015 Elsevier Ltd. All rights reserved.
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| 7. |
- Eliasson, Lovisa, et al.
(author)
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Effect of drying technique and particle size of bilberry press cake on the extraction efficiency of anthocyanins by pressurized carbon dioxide extraction
- 2017
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In: Lebensmittel-Wissenschaft + Technologie. - : Elsevier BV. - 0023-6438 .- 1096-1127. ; 85, s. 510-516
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Journal article (peer-reviewed)abstract
- To improve the extraction efficiency of anthocyanins from bilberry press cake using pressurized carbon dioxide, the combined effect of drying technique and bilberry press cake particle size was assessed. Pressurized carbon dioxide using ethanol as co-solvent was compared with a simple and efficient solvent extraction using methanol. The press cake with large (>710 mm) size particles had a higher anthocyanins content (84 g/kg dry matter to 87 g/kg dry matter) than did the small (<710 mm) size particles (60 g/kg dry matter to 65 g/kg dry matter). Although, the large size particles contained more anthocyanins, more efficient anthocyanins extraction using pressurized carbon dioxide extraction was obtained with the small than the large size particles. The press cake dried by freeze-drying generated a powder with smaller particles and lower bulk density than either the microwave-assisted hot-air-dried or hot-airdried powders. In comparison to methanol extraction, the most efficient anthocyanins extraction was obtained from the freeze-dried small size particles. This work showed that there is a potential to improve the extraction efficiency of anthocyanins extracted by pressurized carbon dioxide by selecting appropriate drying technology and particle size distribution of the press cake.
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| 8. |
- Galanakis, Charis M., et al.
(author)
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A study of the recovery of the dietary fibres from olive mill wastewater and the gelling ability of the soluble fibre fraction
- 2010
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In: LWT - Food Science and Technology. - : Elsevier BV. - 0023-6438. ; 43:7, s. 1009-1017
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Journal article (peer-reviewed)abstract
- A novel method of the recovery of a dietary fibre containing material from olive mill wastewater (OMW) was developed. Extraction was based on thermal treatment with mixtures of ethanol and acids, prior to the isolation of the alcohol insoluble residue (AIR). Different mixtures were tested and the extracted residues were characterized. The maximum AIR recovery accounted 64.8 g/100 g OMW dry matter, while the corresponding total fibre content was 5.1 g/100 g of the AIR. Despite the high potassium (8.4 g/100 g) and the low galacturonic acid content (3.3 g/100 g), AIR was able to form gels after a simple isolation and concentration of the soluble fraction. The soluble fibres were exclusively composed of pectin (93.9 and 6.1 mol/100 mol galacturonic acid and arabinose, respectively) with 59 mol/100 mol GalA degree of methylation. The viscoelastic properties of the gels were evaluated as a function of galacturonic acid content, where the gel rigidity and elasticity was found to increase exponentially with this parameter. A further treatment of the pectin material with citric acid during its concentration, allowed the formation of more rigid, but less elastic gels. (C) 2010 Elsevier Ltd. All rights reserved.
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| 9. |
- Galanakis, Charis M., et al.
(author)
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Dietary fiber suspensions from olive mill wastewater as potential fat replacements in meatballs
- 2010
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In: LWT - Food Science and Technology. - : Elsevier BV. - 0023-6438. ; 43:7, s. 1018-1025
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Journal article (peer-reviewed)abstract
- A dietary fiber containing material, named as alcohol insoluble residue (AIR), was recovered from the olive mill wastewater (OMW). It was separated into different fractions (water soluble and insoluble AIR) and characterized with regard to fiber and ion content. Dynamic rheological tests of the water soluble fraction (WSAIR) were conducted in order to examine its gelling ability. Thereafter, AIR as well as WSAIR were utilized as fat replacement in meatballs together or separately with carrot and starch and compared with regard to the total, water and fat loss or oil uptake during frying of the meatballs. Results indicated that AIR could not be considered as a potential fat replacement in meatballs due to the restricted water holding ability. Nevertheless, WSAIR could be utilized together with carrot fibers as additive in low fat meatballs, since it was able to improve the cooking properties of the product, by restricting the oil uptake and thereby giving rise to meatballs with sustained reduced fat content. (C) 2009 Elsevier Ltd. All rights reserved.
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| 10. |
- Galanakis, Charis M., et al.
(author)
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The effect of heat processing on the functional properties of pectin contained in olive mill wastewater
- 2010
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In: LWT - Food Science and Technology. - : Elsevier BV. - 0023-6438. ; 43:7, s. 1001-1008
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Journal article (peer-reviewed)abstract
- The purpose of this study was to evaluate the effect of prolonged heat processing (180 min at 50-80 degrees C) on the functional and theological properties of pectin, derived from olive mill wastewater (OMW). It was shown that a low temperature blanching of OMW at 60 degrees C, activates endogenous pectin methyl esterase and promotes demethylation, despite the high concentration of phenols. Activation of the enzyme resulted in enhanced solubilization and subsequent partial degradation of pectin. The induced degradation impaired pectin grade and resulted in loss of gelling functionality. An alternative heating process at 80 degrees C resulted in negligible enzyme induced degradation of the pectin and improved gelling properties of the recovered material, despite the lower solubilization of the pectin. The obtained results contribute to a better understanding of the temperature effect on pectin functional properties and can be utilized in order to optimize pectin recovery from OMW. (C) 2010 Elsevier Ltd. All rights reserved.
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