| 1. |
- Palmer, Nicholette D, et al.
(författare)
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A genome-wide association search for type 2 diabetes genes in African Americans.
- 2012
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Ingår i: PloS one. - San Francisco : Public Library of Science (PLoS). - 1932-6203. ; 7:1, s. e29202-
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Tidskriftsartikel (refereegranskat)abstract
- African Americans are disproportionately affected by type 2 diabetes (T2DM) yet few studies have examined T2DM using genome-wide association approaches in this ethnicity. The aim of this study was to identify genes associated with T2DM in the African American population. We performed a Genome Wide Association Study (GWAS) using the Affymetrix 6.0 array in 965 African-American cases with T2DM and end-stage renal disease (T2DM-ESRD) and 1029 population-based controls. The most significant SNPs (n = 550 independent loci) were genotyped in a replication cohort and 122 SNPs (n = 98 independent loci) were further tested through genotyping three additional validation cohorts followed by meta-analysis in all five cohorts totaling 3,132 cases and 3,317 controls. Twelve SNPs had evidence of association in the GWAS (P<0.0071), were directionally consistent in the Replication cohort and were associated with T2DM in subjects without nephropathy (P<0.05). Meta-analysis in all cases and controls revealed a single SNP reaching genome-wide significance (P<2.5×10(-8)). SNP rs7560163 (P = 7.0×10(-9), OR (95% CI) = 0.75 (0.67-0.84)) is located intergenically between RND3 and RBM43. Four additional loci (rs7542900, rs4659485, rs2722769 and rs7107217) were associated with T2DM (P<0.05) and reached more nominal levels of significance (P<2.5×10(-5)) in the overall analysis and may represent novel loci that contribute to T2DM. We have identified novel T2DM-susceptibility variants in the African-American population. Notably, T2DM risk was associated with the major allele and implies an interesting genetic architecture in this population. These results suggest that multiple loci underlie T2DM susceptibility in the African-American population and that these loci are distinct from those identified in other ethnic populations.
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| 2. |
- Czink, Nicolai, et al.
(författare)
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General discussion
- 2012
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Ingår i: Faraday Discussions. - 1359-6640. ; 158, s. 239-266
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Marefati, Ali, et al.
(författare)
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Freezing and freeze-drying of Pickering emulsions stabilized by starch granules
- 2013
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Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - : Elsevier BV. - 0927-7757. ; 436, s. 512-520
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the possibility to produce novel powder materials based on chemically modified starch granule stabilized Pickering oil-in-water (O/W) emulsions. This study also investigated the effect of partial starch gelatinization in situ, dispersed phase type (two oil types with different melting points), freezing method and thawing, and freeze-drying and rehydrating on the overall properties of the emulsions. The emulsions showed high freeze thaw stability. The results of this study demonstrated the feasibility of the production of oil containing hydrocolloid-based powders, through combination of heat treated or even non-heat treated starch Pickering emulsions and freeze-drying. The final powders comprised high weight percentage of oil (over 80%, w/w). Upon rehydration of powders, the starch stabilized oil drops were found to be only moderately affected by the process with some aggregation observed. (C) 2013 Elsevier B.V. All rights reserved.
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| 4. |
- Marku, Diana, et al.
(författare)
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Characterization of starch Pickering emulsions for potential applications in topical formulations.
- 2012
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Ingår i: International Journal of Pharmaceutics. - : Elsevier BV. - 1873-3476 .- 0378-5173. ; 428:1-2, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work has been to characterize starch based Pickering emulsions as a first step to evaluate their possible use as vehicles for topical drug delivery. A minor phase study of emulsions with high oil content has been performed. Emulsion stability against coalescence over eight weeks and after mild centrifugation treatment has been studied. The particle size, rheological properties and in vitro skin penetration of emulsions containing three different oils (Miglyol, paraffin and sheanut oil) was investigated. It was shown that it is possible to produce oil in water starched stabilised Pickering emulsions with oil content as high as 56%. Furthermore, this emulsions show good stability during storage over eight weeks and towards mild centrifugation. The particle size of the systems are only dependent on the ratio between oil and starch and for liquid oils the type of oil do not affect the particle size. The type of oil also affects the cosmetic and rheological properties of the creams but did not affect the transdermal diffusion in in vitro tests. However, it seems as if the Pickering emulsions affected the transport over the skin, as the flux was twice that of what has been previously reported for solutions.
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| 5. |
- Matos, María, et al.
(författare)
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Preparation and encapsulation properties of double Pickering emulsions stabilized by quinoa starch granules
- 2013
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Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - : Elsevier BV. - 0927-7757. ; 423, s. 147-153
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Tidskriftsartikel (refereegranskat)abstract
- Double emulsions have potential applications in the food, cosmetic and pharmaceutical industries as vehicles for encapsulation and delivery of nutrients during food digestion or as drug release. The major drawback of this type of emulsions is that they are often difficult to stabilize. Particle stabilized emulsions, known as Pickering emulsions, show special features, such as being extremely stable with respect to coalescence. Starch granules have proved to be a suitable stabiliser for food grade Pickering emulsions. In this work, starch double W1/O/W2 Pickering emulsions were prepared and their encapsulation stability was studied as well as the impact of varying the lipophilic emulsifier (PGPR90) content and salt concentration in the W1 inner aqueous phase. Encapsulation properties were quantified by monitoring the release of a hydrophilic dye from the inner aqueous phase spectrophotometrically. Two double emulsion systems were studied, one with an inner aqueous phase with 0.1M NaCl and the other with 0.2M NaCl. The initial encapsulation efficiency was over 98.5% immediately after emulsification production. The encapsulation stability (ES) remained over 90% after 21 days for both systems studied, where 0.1 M NaCl W1 emulsion had a ES of 95.2% and the 0.2 M NaCl W1 emulsion had a ES of 91.1% respectively.
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| 6. |
- Montelius, Caroline, et al.
(författare)
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Chloroplast thylakoids reduce glucose uptake and decrease intestinal macromolecular permeability.
- 2011
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Ingår i: British Journal of Nutrition. - 1475-2662. ; 106:6, s. 836-844
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Tidskriftsartikel (refereegranskat)abstract
- Thylakoid membranes, derived from chloroplasts, have previously been shown to retard fat digestion and lower blood glucose levels after oral intake. The purpose of the present study was to investigate the effect of thylakoid membranes on the passage of methyl-glucose, dextran and ovalbumin over rat intestine in vitro using Ussing chambers. The results show that thylakoids retard the passage of each of the test molecules in a dose-dependent way. The thylakoids appear to be attached on the mucosal surface and a mechanism is suggested that the thylakoids delay the passage of the test molecules by sterical hindrance. The present results indicate that thylakoid membranes may be useful both to control intestinal absorption of glucose and to enhance the barrier function of the intestine.
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| 7. |
- Rayner, Marilyn, et al.
(författare)
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A novel emulsifier from spinach with appetite regulation abilities
- 2011
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Ingår i: Procedia Food Science. - : Elsevier BV. - 2211-601X. ; 1, s. 1431-1438
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Tidskriftsartikel (refereegranskat)abstract
- Chloroplast thylakoid membranes inhibit pancreatic lipase/colipase activity in vitro and, when included in food, induce satiety signals. This effect is due to their ability to reduce the rate of lipolysis through the inhibition of the lipase-colipase complex. They have a strong affinity to oil which both prevents the lipolytic enzymes from in close contact with its substrate and at the same time protects the thylakoids form proteolytic enzymes present in gastric juices form digesting the thylakoids as quickly. This affinity also imparts thylakoids interesting emulsification properties. The objective of this study was to characterize thylakoids’ ability to stabilize oil-in-water emulsions, and to study their interfacial properties in light of their capacity to inhibit pancreatic lipase-co lipase activity in vitro. As lipolysis is an inherently interfacial process it is important to quantify their interfacial properties and to maximize the oil-water interfacial area covered by the thylakoids in future food formulations. Thylakoids isolated from spinach were used for emulsification studies using a lab-scale high shear homogenizer. The oil-in-water emulsions produced had varying amounts of thylakoids and resulting emulsions were characterized by creaming phase volume, microscopy and light scattering to determine microstructure and droplet size distributions as well as surface load. Electron micrographs showed thylakoids adsorbed as loosely bunched vesicles on the drop surfaces approximately 1 micron in size, and were found to effectively stabilize the oil water interface, but with large droplet size (20 to 200 micron range) and relatively high surface loads (2 to 10 mg/m2).
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| 8. |
- Rayner, Marilyn, et al.
(författare)
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Biomass-based particles for the formulation of Pickering type emulsions in food and topical applications
- 2014
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Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - : Elsevier BV. - 0927-7757. ; 458, s. 48-62
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Tidskriftsartikel (refereegranskat)abstract
- Pickering emulsions are emulsions that are stabilized by fine particles. They have been the focus of considerable research in the past decade due to their properties such as high stability with respect to coalescence and Ostwald ripening, as well as due to advances in nanotechnology that allows us to create and characterize nano-scale structures in new ways. This work reviews some of the recent work in the area of biomass-based particles for Pickering emulsions in the context of foods and topical creams, and discusses some of the theory and particularities of Pickering type emulsions. Formulation examples are given with a focus on two types of biomass-based particles isolated with their natural structure intact: starch granules from quinoa and egg yolk granules. In contrast to particles commonly used for Pickering emulsions such as latex, silica, and clay particles, starch (including hydrophobically modified starch) and egg-fractions are accepted food ingredients, as well as pharmaceutical and cosmetic excipients. The particle stabilization of emulsion drops is possible due to partial dual wettability of particles at the oil-water interface. Native starch is not intrinsically hydrophobic; however hydrophobicity can be increased by chemical modification with octenyl succinic anhydride. Egg-granules on the other hand are quite hydrophobic and at low ionic strength (<0.3 M NaCl) are insoluble with a compact structure. Quinoa starch granules and egg-granules can be used to generate Pickering type emulsions in the 10-100 mu m range with high levels of stability. Size decreased with increasing concentration and could be controlled by the granule to oil ratio. In the case of starch granule stabilized oil drops, heat can be applied to induce a partial gelatinization of the starch granules forming a cohesive layer at the oil-water interface increasing barrier properties. Although the droplet size of granule stabilized emulsions was relatively large, their excellent stability, encapsulation properties, and freeze-thaw stability can prove suitable for applications such as encapsulation of sensitive, bioactive ingredients in food and topical formulations. (C) 2014 Elsevier B.V. All rights reserved.
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| 9. |
- Rayner, Marilyn, et al.
(författare)
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Chloroplast thylakoid membrane-stabilised emulsions.
- 2011
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Ingår i: Journal of the Science of Food and Agriculture. - : Wiley. - 1097-0010 .- 0022-5142. ; 91:2, s. 315-321
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Thylakoid-stabilised emulsions have been reported to possess satiety-promoting effects and inhibit pancreatic lipase-colipase activity in vitro, which prompted the investigation of their interfacial properties.RESULTS: Thylakoid membranes isolated from spinach were used as an emulsifier/stabiliser in oil (triglyceride)-in-water emulsions. Emulsions were characterised with respect to droplet size, interfacial tension, creaming, surface load and electron microscopy. The effects of pH and thylakoid concentration were also considered. Droplet size decreased with increasing thylakoid concentration, reaching a plateau around 15 microm beyond concentrations of 2 mg protein mL(-1) oil. The resulting emulsions were stable against coalescence but were subject to creaming. The surface pressure (air/water interface) of the thylakoid isolate was 44 mN m(-1) and the surface load 13 mg m(-2) at 10 mg protein mL(-1) oil. Electron micrographs showed thylakoids adsorbed as bunched vesicles on the drop surfaces. The stabilisation mechanism can be described as a combined effect of surface-active molecules, mainly membrane proteins but also membrane lipids, exposed on surfaces of thylakoid membrane vesicles adsorbed as particles.CONCLUSION: Thylakoid membranes effectively stabilise oil-in-water emulsions, which should facilitate their incorporation in food with satiety-promoting effects. To the authors' knowledge, this is the first study on the emulsifying properties of an isolated biological membrane as a functional ingredient.
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| 10. |
- Rayner, Marilyn, et al.
(författare)
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Quinoa starch granules: a candidate for stabilising food-grade Pickering emulsions.
- 2012
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Ingår i: Journal of the Science of Food and Agriculture. - : Wiley. - 1097-0010 .- 0022-5142. ; 92:9, s. 1841-1847
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Particle-stabilised emulsions, so-called Pickering emulsions, are known to possess many beneficial properties, including being extremely stable. Starch granules isolated from quinoa have been used as emulsion stabilising particles. The granules were intact, 1-3 µm in diameter and modified with octenyl succinic anhydride to increase their hydrophobicity. Starch granules, as opposed to most other particles used to generate Pickering emulsions, are edible, abundant and derived from natural sources. RESULTS: Emulsions produced by high shear homogenisation had droplet sizes of 9-70 µm depending on the starch-to-oil ratio. Droplet size decreased with increasing starch-to-oil ratio, but was unaffected by the oil phase volume over a range of 5-33% oil (v/v). Although the drops were large and subject to creaming, their size remained unchanged over a period of 7 days. By adjusting the starch-to-oil ratio drops could be made to be buoyancy neutral to prevent creaming. Rheological characterisation indicated a gel structure with an elastic modulus in the range 200-2000 Pa depending on droplet size. CONCLUSION: This work has demonstrated the successful use of starch granules to stabilise emulsions which may find applications beyond that of food, for example in cosmetics and pharmaceutical formulations. Copyright © 2012 Society of Chemical Industry.
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| 11. |
- Rayner, Marilyn, et al.
(författare)
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Quinoa starch granules as stabilizing particles for production of Pickering emulsions
- 2012
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Ingår i: Faraday Discussions. - 1364-5498. ; 158, s. 139-155
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Tidskriftsartikel (refereegranskat)abstract
- Intact starch granules isolated from quinoa (Chenopodium quinoa Willd.) were used to stabilize emulsion drops in so-called Pickering emulsions. Miglyol 812 was used as dispersed phase and a phosphate buffer (pH7) with different salt (NaCl) concentrations was used as the continuous phase. The starch granules were hydrophobically modified to different degrees by octenyl succinic anhydride (OSA) or by dry heat treatment at 120 [degree]C in order to study the effect on the resulting emulsion drop size. The degree of OSA-modification had a low to moderate impact on drop size. The highest level of modification (4.66%) showed the largest mean drop size, and lowest amount of free starch, which could be an effect of a higher degree of aggregation of the starch granules and, thereby, also the emulsion drops stabilized by them. The heat treated starch granules had a poor stabilizing ability and only the starch heated for the longest time (150 min at 120 [degree]C) had a better emulsifying capacity than the un-modified native starch granules. The effect of salt concentration was rather limited. However, an increased concentration of salt slightly increased the mean drop size and the elastic modulus.
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| 12. |
- Timgren, Anna, et al.
(författare)
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Emulsion stabilizing capacity of intact starch granules modified by heat treatment or octenyl succinic anhydride
- 2013
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Ingår i: Food Science & Nutrition. - : Wiley. - 2048-7177. ; 1:2, s. 71-157
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Tidskriftsartikel (refereegranskat)abstract
- Starch granules are an interesting stabilizer candidate for food-grade Pickering emulsions. The stabilizing capacity of seven different intact starch granules for making oil-in-water emulsions has been the topic of this screening study. The starches were from quinoa; rice; maize; waxy varieties of rice, maize, and barley; and high-amylose maize. The starches were studied in their native state, heat treated, and modified by octenyl succinic anhydride (OSA). The effect of varying the continuous phase, both with and without salt in a phosphate buffer, was also studied. Quinoa, which had the smallest granule size, had the best capacity to stabilize oil drops, especially when the granules had been hydrophobically modified by heat treatment or by OSA. The average drop diameter (d 32) in these emulsions varied from 270 to 50 μm, where decreasing drop size and less aggregation was promoted by high starch concentration and absence of salt in the system. Of all the starch varieties studied, quinoa had the best overall emulsifying capacity, and OSA modified quinoa starch in particular. Although the size of the drops was relatively large, the drops themselves were in many instances extremely stable. In the cases where the system could stabilize droplets, even when they were so large that they were visible to the naked eye, they remained stable and the measured droplet sizes after 2 years of storage were essentially unchanged from the initial droplet size. This somewhat surprising result has been attributed to the thickness of the adsorbed starch layer providing steric stabilization. The starch particle-stabilized Pickering emulsion systems studied in this work has potential practical application such as being suitable for encapsulation of ingredients in food and pharmaceutical products.
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| 13. |
- Timgren, Anna, et al.
(författare)
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Starch particles for food based Pickering emulsions
- 2011
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Ingår i: Procedia Food Science. - : Elsevier BV. - 2211-601X. ; 1, s. 95-103
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Tidskriftsartikel (refereegranskat)abstract
- Intact starch granules are a new source of particles for stabilizing emulsions, so called Pickering emulsions. Small (1-2 μm) and uni-modal starch granules at various concentrations have been used in this study to investigate the stability of the emulsions, the drop size dependence of the starch concentration and the barrier properties of the stabilizing starch layer upon heating. The granules were modified with octenyl succinic anhydride (OSA) to increase the hydrophobicity. The drops in the emulsions prepared in this study were in the 10-100 μm range depending on the starch concentration, and the drop size decreased with an increased amount of added starch granules. During the 8 week storage, the emulsion drops were stable to coalescence and the volume occluded by the emulsion phase was unaffected or even increased. In order to increase the barrier properties at the oil-water interface the emulsions were gently heated, which induced a partial gelatinization of the starch granules. The efficiency of the barrier was characterized by a lipolysis experiment where the activity of lipase was measured. The activity of lipase was decreased with nearly 70% compared to an unheated starch stabilized emulsion, which will be useful in applications where a controlled release of specific substances in the gastro intestinal tract is desirable.
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| 14. |
- Voight, Benjamin F., et al.
(författare)
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Twelve type 2 diabetes susceptibility loci identified through large-scale association analysis
- 2010
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 42:7, s. 579-589
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Tidskriftsartikel (refereegranskat)abstract
- By combining genome-wide association data from 8,130 individuals with type 2 diabetes (T2D) and 38,987 controls of European descent and following up previously unidentified meta-analysis signals in a further 34,412 cases and 59,925 controls, we identified 12 new T2D association signals with combined P < 5 x 10(-8). These include a second independent signal at the KCNQ1 locus; the first report, to our knowledge, of an X-chromosomal association (near DUSP9); and a further instance of overlap between loci implicated in monogenic and multifactorial forms of diabetes (at HNF1A). The identified loci affect both beta-cell function and insulin action, and, overall, T2D association signals show evidence of enrichment for genes involved in cell cycle regulation. We also show that a high proportion of T2D susceptibility loci harbor independent association signals influencing apparently unrelated complex traits.
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| 15. |
- Wahlgren, Marie, et al.
(författare)
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The Use of Micro- and Nanoparticles in the Stabilisation of Pickering-Type Emulsions for Topical Delivery
- 2013
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Ingår i: Current Pharmaceutical Biotechnology. - : Bentham eBooks. - 1389-2010 .- 1873-4316. ; 14:15, s. 1222-1234
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Tidskriftsartikel (refereegranskat)abstract
- This review describes the use of Pickering emulsions for topical drug delivery. The focus is on Pickering emulsions and how to formulate these. However, a short description of the challenges of topical drug delivery is also given. The article describes how Pickering emulsions might have other properties than traditional topical creams. It is our believe that Pickering emulsions could give added value to topical formulations as it is surfactant free, has new properties, and may alter the transport of drugs across the skin barrier.
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| 16. |
- Östbring, Karolina, et al.
(författare)
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The effect of heat treatment of thylakoids on their ability to inhibit in vitro lipase/co-lipase activity.
- 2014
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Ingår i: Food & Function. - : Royal Society of Chemistry (RSC). - 2042-6496 .- 2042-650X. ; 5:9, s. 2157-2165
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Tidskriftsartikel (refereegranskat)abstract
- Thylakoids has been shown to prolong lipolysis by the inhibition of lipase/co-lipase, which makes thylakoids suitable as a functional food ingredient with satiating properties. The components of thylakoids that provide its function as a lipolysis modulator are primarily photosystems I and II, which are structurally stabilised by chlorophyll. However, chlorophyll is known to be heat sensitive yet the enzymatic inhibiting capacity after heat treatment has not been previously studied. It was hypothesised that the retained function of thylakoids after heat treatment could be correlated to the degree of degradation. Heat treatment at either 60 °C, 75 °C or 90 °C for time interval ranging from 15 s to 120 min induced a color shift from bright green to olive brown which was attributed to degradation. The ability of heat-treated thylakoids to inhibit lipolysis in vitro was also reduced. A correlation between chlorophyll a degradation and the enzymatic inhibiting capacity could be established which opens possibilities to use a spectrophotometric method to quantify the ability of thylakoids to inhibit lipase/co-lipase in a more rapid and cost effective way to complement the pH-stat method used today. With the degradation pattern investigated, it is then possible to design a thermal treatment process to ensure a microbiological safe appetite-reducing product and at the same time minimize the loss of functionality.
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