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1.
Br J Nutr ; 130(9): 1521-1536, 2023 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-36847278

RESUMO

Only 6 to 8 % of the UK adults meet the daily recommendation for dietary fibre. Fava bean processing lead to vast amounts of high-fibre by-products such as hulls. Bean hull fortified bread was formulated to increase and diversify dietary fibre while reducing waste. This study assessed the bean hull: suitability as a source of dietary fibre; the systemic and microbial metabolism of its components and postprandial events following bean hull bread rolls. Nine healthy participants (53·9 ± 16·7 years) were recruited for a randomised controlled crossover study attending two 3 days intervention sessions, involving the consumption of two bread rolls per day (control or bean hull rolls). Blood and faecal samples were collected before and after each session and analysed for systemic and microbial metabolites of bread roll components using targeted LC-MS/MS and GC analysis. Satiety, gut hormones, glucose, insulin and gastric emptying biomarkers were also measured. Two bean hull rolls provided over 85 % of the daily recommendation for dietary fibre; but despite being a rich source of plant metabolites (P = 0·04 v. control bread), these had poor systemic bioavailability. Consumption of bean hull rolls for 3 days significantly increased plasma concentration of indole-3-propionic acid (P = 0·009) and decreased faecal concentration of putrescine (P = 0·035) and deoxycholic acid (P = 0·046). However, it had no effect on postprandial plasma gut hormones, bacterial composition and faecal short chain fatty acids amount. Therefore, bean hulls require further processing to improve their bioactives systemic availability and fibre fermentation.


Assuntos
Fabaceae , Hormônios Gastrointestinais , Adulto , Humanos , Voluntários Saudáveis , Putrescina , Pão/análise , Cromatografia Líquida , Estudos Cross-Over , Espectrometria de Massas em Tandem , Fibras na Dieta/análise , Fabaceae/metabolismo , Ácido Desoxicólico , Glicemia/análise
2.
J Food Sci Technol ; 59(10): 4037-4044, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36193361

RESUMO

Lycopene is a highly potent antioxidant that is prevalent among dietary carotenoids. However, its use in food formulations is restricted due to its poor water-solubility and proneness to oxidation. The aim of this research was to encapsulate lycopene in yogurt using emulsion technology for improving its stability during processing and storage, in order to diversify a widely consumed food product and enhance its nutritional value. Confocal laser microscopy data showed that the incorporation of oil droplets with emulsification did not have a negative effect on the formation and microstructure of yogurt. Syneresis of lycopene-fortified yogurt samples was approximately twice as high compared with plain yogurt at day 7; the ability to retain water was significantly improved with storage time for all emulsified samples. Additionally, storage reduced the Turbiscan Stability Indices (TSI) for all yogurt samples, which suggests that physical stability improved at 4 °C. Emulsification resulted in increased oxidation levels due to increased oil content. This effect was ameliorated by lycopene encapsulation, which effectively protected corn oil from oxidation and prevented degradation. This study indicates that emulsification is a promising method for lycopene encapsulation and can be used for developing yogurt with desirable nutritional properties.

3.
Nutr Health ; : 2601060221105744, 2022 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-35695231

RESUMO

Background: Non-Dairy (ND) food consumption is rapidly increasing in the UK and for many consumers plant-based diets are presumed to be healthier than standard diets. ND alternatives have different nutritional compositions, and their consumption could present challenges on a public-health level. Aim: To compare the price and nutritional composition of dairy and ND milks and cheeses in UK supermarkets. Methods: Macro and micronutrient data was recorded from Alpro's website and the 6 leading UK grocers for their own-label ND milks and cheeses. For missing micronutrient values the McCance & Widdowson's dataset was used. 99 total products were extracted: 57 ND milks, 7 dairy milks, 10 dairy cheeses and 25 ND cheeses. Dairy milk and cheese were used as control against which all ND products were compared. Results: Soya and coconut milks had lower values of carbohydrates, sugars, calcium, iodine, and potassium (p < 0.01) than dairy. Almond milk had lower values of carbohydrates (p = 0.01), sugars, calcium, iodine, and potassium (p < 0.01) compared to dairy milk. Protein was significantly (p < 0.01) lower for all ND except soya. Dairy cheeses had higher values for energy, protein, iodine, potassium, riboflavin, vitamin B12 and calcium (p < 0.01) than ND. Median prices were similar between dairy and ND milks, whereas ND cheeses were significantly more expensive compared to dairy (p < 0.01). Conclusions: ND alternatives fall short in several key nutrients compared to dairy. Fortification, accurate labelling and nutrition education are needed to help consumers make healthy and informed choices.

4.
Molecules ; 26(6)2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33801934

RESUMO

Yogurt is a nutritious food that is regularly consumed in many countries around the world and is widely appreciated for its organoleptic properties. Despite its contribution to human dietary requirements, yogurt in its traditional recipe is a poor source of fat-soluble vitamins. To respond to consumer demands and further increase the nutritional value of this product, this work aimed to fortify yogurt with vitamin E by using emulsification as the method of encapsulation. The effects of thermal processing and chilled storage on the physicochemical stability of the yogurt-based beverage was investigated. Vitamin E was only minorly affected by bulk pasteurization at 63 °C for 30 min and remained stable during storage at 4 °C for 28 days. Fortified samples showed increased in vitro antioxidant activity compared with non-fortified samples. Lactic acid bacterial counts were above the minimum recommended levels (>106 cfu/g) after processing and storage. In conclusion, this work has demonstrated that emulsification can be an effective strategy for developing yogurt-based products fortified with fat soluble vitamins.


Assuntos
Encapsulamento de Células/métodos , Vitamina E/análise , Iogurte/análise , Animais , Técnicas de Cultura Celular por Lotes/métodos , Bebidas , Emulsões/química , Emulsões/farmacologia , Fermentação , Manipulação de Alimentos , Alimentos Fortificados/análise , Leite/química , Pasteurização/métodos , Vitamina E/química
5.
Food Sci Nutr ; 8(12): 6426-6432, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33312528

RESUMO

Despite high consumer demands, the manufacture of nondairy yogurt from oat milk is currently hindered due to the lack of consistency and texture. An oat-based yogurt was developed using oat milk and probiotics (Streptococcus thermophilus and Lactobacillus bulgaricus) with aquafaba (AF) and vegetable oil (VO) as added ingredients. Physicochemical analyses and viability of probiotics were investigated after yogurt formation and for 3 weeks under refrigerated storage. Results showed that adding AF decreased syneresis and increased water holding capacity during storage. Both AF and VO had a beneficial effect on hardness, the most important textural property of yogurt. Confocal laser scanning microscopy revealed that the added ingredients played a major role in the formation of the gel network structure of the yogurt. Both Streptococcus thermophilus and Lactobacillus bulgaricus remained at acceptable levels > 8.28 Log CFU/g and > 5.79 Log CFU/g after 3 weeks at 4°C regardless of the added ingredients.

6.
Foods ; 9(9)2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32872269

RESUMO

The seed coat (hull) of broad bean (Vicia faba) (BBH) is a significant secondary product of processing with a promising nutritional profile. Bean hull has a high fiber content (49%), yet it remains underexploited as an ingredient by the food industry. This study investigated the potential of this secondary product to partially replace wheat flour for the development of high-fiber breads. Bread formulations with a range of supplementation levels (0%, 11%, 21% and 31%) were developed and tested for their nutritional and physical properties. The proximate composition of breads revealed that at 31% replacement, the fiber content was 19.19 g/100 g bread, which was significantly higher (p < 0.05) than control breads (3.62 g/100 g bread). The physical (specific volume, density and color) and textural properties of breads were affected by the addition of bean hull. Specific volume and hardness of breads were significantly reduced at ≥21% replacement compared to the control, which may reduce acceptability of the product by some consumer groups. Enzyme-linked immunosorbent assay (ELISA) showed that the gluten content of breads was significantly reduced with bean hull addition (62% depletion for 31% replacement). At 11%, 21% and 31% replacement, one portion (80 g of bread) contains 6.8 g, 11.6 g and 15.3 g of dietary fiber, respectively, which contributes 23%, 38% and 51% of the recommended daily fiber intake (30 g/day). In conclusion, bean hull can be a valuable source of dietary fiber in bread formulations. The study showed BBH could be used to replace up to 21% of the wheat flour without significantly impacting on bread texture and volume.

7.
Foods ; 9(4)2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32260066

RESUMO

Legumes are a source of health-promoting macro- and micronutrients, but also contain numerous phytochemicals with useful biological activities, an example of which are saponins. Epidemiological studies suggest that saponins may play a role in protection from cancer and benefit human health by lowering cholesterol. Therefore, they could represent good candidates for specialised functional foods. Following the consumption of a soya-rich high-protein weight-loss diet (SOYA HP WL), the concentrations of Soyasaponin I (SSI) and soyasapogenol B (SSB) were determined in faecal samples from human volunteers (n = 10) and found to be between 1.4 and 17.5 mg per 100 g fresh faecal sample. SSB was the major metabolite identified in volunteers' plasma (n = 10) after consumption of the soya test meal (SOYA MEAL); the postprandial (3 h after meal) plasma concentration for SSB varied between 48.5 ng/mL to 103.2 ng/mL. The metabolism of SSI by the gut microbiota (in vitro) was also confirmed. This study shows that the main systemic metabolites of soyasaponin are absorbed from the gut and that they are bioavailable in plasma predominantly as conjugates of sapogenol. The metabolism and bioavailability of biologically active molecules represent key information necessary for the efficient development of functional foods.

8.
Heliyon ; 4(10): e00875, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30386826

RESUMO

In this study aqueous extracts from salal berry (SB) and blackcurrant pomace (BCP) were used to reformulate yogurt and the anti-diabetic properties of the beverage were investigated during 4 weeks of cold storage at 4 °C. Results indicated that α-amylase, α-glucosidase and DPP-IV inhibitory activities increased with storage time for all samples. At the end of storage period α-amylase, α-glucosidase and DPP-IV inhibition were >61%, 62% and 56% respectively for all yogurt types. This increase in bioactivity during cold storage is attributed to the viability of lactic acid bacteria (∼108 cfu/g), which is maintained for 4 weeks. Enzyme inhibition increased similarly for all yogurt types at 4 °C except for α-glucosidase. Yogurt with BCP showed the highest potency to inhibit α-glucosidase (>90%) with an IC50 value of 0.20 mg/ml (week 4). A peptidomic approach based on liquid chromatography coupled with mass spectrometry (LC-MS) was used for the separation and identification of peptides generated in three types of yogurt. A total of 486 peptides mainly from caseins were identified, of which 15 have documented bioactivity, predominantly as antimicrobial agents or ACE-inhibitors.

9.
J Food Sci Technol ; 55(7): 2401-2409, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30042555

RESUMO

Oxidation is a significant problem in processed foods affecting their physico-chemical, shelf life and health properties. Natural antioxidants could be viable alternatives to synthetic variants for safely improving antioxidation properties of processed foods. The aim of this study was to assess the singular and combined effects of beetroot and chocolate on the oxidative stability of a high fat and protein processed food (sponge cake) during storage and gastrointestinal digestion. Cakes were prepared and assessed for antioxidant potential, polyphenols, and oxidative stability, and macronutrient oxidation during simulated gastro-intestinal digestion. Beetroot significantly improved the antioxidant and polyphenol profiles of sponge cake which further improved with chocolate addition. Beetroot also significantly increased the oxidative stability and shelf-life of sponge cake, and these effects were enhanced when combined with chocolate. Chocolate significantly reduced lipid oxidation during the gastric phase of digestion. However, both chocolate and beetroot did not curtail lipid oxidation in the intestinal phase, nor protein oxidation at any of the phases. Promisingly, beetroot and chocolate addition did not affect textural parameters and delayed staling by up to 2 days. Overall, the benefits of beetroot and chocolate addition were manifested more in the food system than during its digestion. Beetroot improves the oxidative stability and shelf life of processed foods, and its effects could be enhanced through combining with other natural products.

10.
J Dairy Sci ; 101(7): 5821-5831, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29705412

RESUMO

Powdered ß-glucan extracted from brewer's yeast (Yestimun, Leiber GmbH, Bramsche, Germany) was incorporated into skimmed-milk yogurt at varying concentrations (0.2-0.8% wt/wt) to investigate its potential application as a thickener. The effect of ß-glucan fortification on the nutritional profile, microstructure, physicochemical properties, and texture of freshly prepared yogurts was investigated. Sensory evaluation was also conducted and was correlated with instrumental analysis. The addition of Yestimun significantly reduced the fermentation time of the yogurt mix from 4 h to 3 h. Scanning electron microscopy revealed that ß-glucan particles formed small spherical clusters within the yogurt matrix. The majority of the physicochemical properties (syneresis, viscosity, color, and titratable acidity) remained unaffected by the incorporation of Yestimun in the recipe. Textural properties showed a gradual increment with increasing ß-glucan concentration. Hardness, total work done, adhesive force, and adhesiveness increased by 19.27, 23.3, 21.53, and 20.76%, respectively, when using the highest amount of Yestimun powder. Sensory analysis (n = 40) indicated that fortifying yogurt with Yestimun at 0.8% (wt/wt) concentration may affect overall acceptance ratings, which was attributed to adverse flavor and aftertaste effects. However, the overall liking score of the yogurt (5.0/9.0) shows potential for commercialization of the product.


Assuntos
Aditivos Alimentares/análise , Iogurte/análise , beta-Glucanas/análise , Animais , Saccharomyces cerevisiae , Sensação , Iogurte/normas
11.
Food Res Int ; 106: 439-445, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29579945

RESUMO

The influence of carrier oil type on the chemical stability, antioxidant properties and bioaccessibility of lycopene in orange oil-in-water beverage emulsions was investigated. The emulsions were formulated with orange oil (A), which was partially (50%) replaced with tributyrin (B) or corn oil (C) because of their distinctively different fatty acid composition. The addition of corn oil enhanced the physical stability of the beverage during chilled storage by inhibiting Ostwald ripening. The formation of oxidation products was insignificant after storage for 28 days at 4 °C, regardless the type of added oil. Lycopene was more susceptible to chemical degradation in the presence of unsaturated, long chain triglycerides and the retention followed the order: A (87.94%), B (64.41%) and C (57.39%). Interestingly, bioaccessibility of lycopene was significantly lower for emulsions formulated with 50% corn oil as opposed to 100% orange oil as indicated by the simulated in vitro gastric digestion model.


Assuntos
Antioxidantes/química , Bebidas , Óleo de Milho/química , Digestão , Manipulação de Alimentos/métodos , Licopeno/química , Óleos de Plantas/química , Triglicerídeos/química , Água/química , Emulsões , Armazenamento de Alimentos , Suco Gástrico/química , Oxirredução , Fatores de Tempo
12.
Food Funct ; 9(1): 320-330, 2018 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-29177307

RESUMO

This study investigated the effect of carrier oils (short-chain triglycerides (SCT) vs. long-chain triglycerides (LCT)) on the physical stability, chemical degradation, antioxidant properties and bioaccessibility of ß-carotene-loaded orange oil-in-water beverage emulsions. Beverages formulated with 50% LCT (corn oil) were physically more stable compared to the ones with 50% SCT (tributyrin) as indicated by the Turbiscan 32 Stability Indices during chilled storage for 28 days. No chemical degradation of ß-carotene was observed during storage regardless of the carrier oil composition. The formation of primary (conjugated dienes) or secondary (thiobarbituric acid reactive substances) oxidation products at the end of the storage period was insignificant. The bioaccessibility of ß-carotene was significantly affected (P < 0.05) by the type of carrier oil and decreased in the following order: 50% LCT + 50% orange oil > 50% SCT + 50% orange oil > 100% orange oil. The high bioaccessibility of ß-carotene (30.06%) in the beverages formulated with LCTs was attributed to the enhanced solubilisation capacity of the lipophilic carotenoid in mixed micelles after the in vitro digestion protocol.


Assuntos
Antioxidantes/química , Portadores de Fármacos/química , Óleos de Plantas/química , beta Caroteno/química , Disponibilidade Biológica , Óleo de Milho/química , Estabilidade de Medicamentos , Emulsões/química , Triglicerídeos/química , Água/química
13.
Foods ; 5(1)2016 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-28231114

RESUMO

There is increasing emphasis on reformulating processed foods to make them healthier. This study for the first time comprehensively investigated the effects of fortifying bread (containing oil as an ingredient) with freeze-dried vegetables on its nutritional and physico-chemical attributes. Breads fortified with carrot, tomato, beetroot or broccoli were assessed for nutrition, antioxidant potential, storage life, shelf stability, textural changes and macronutrient oxidation. Furthermore, using an in vitro model the study for the first time examined the impact of vegetable addition on the oxidative stability of macronutrients during human gastro-intestinal digestion. As expected, adding vegetables improved the nutritional and antioxidant properties of bread. Beetroot and broccoli significantly improved bread storage life. None of the vegetables significantly affected bread textural changes during storage compared to the control. Lipid oxidation in fresh bread was significantly reduced by all four types of vegetables whilst protein oxidation was lowered by beetroot, carrot and broccoli. The vegetables demonstrated varying effects on macronutrient oxidation during gastro-intestinal digestion. Beetroot consistently showed positive effects suggesting its addition to bread could be particularly beneficial.

14.
Foods ; 5(3)2016 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-28231157

RESUMO

The present article describes the second part of a study investigating the effect of adding vegetables on the nutritional, physico-chemical, and oxidative properties of wheat bread, and specifically focuses on bread that does not contain oil as an added ingredient. Wheat flour breads fortified with freeze-dried carrot, tomato, beetroot or broccoli were developed and assessed for their nutritional composition, antioxidant potential, oxidative stability, and storage properties. Using a simulated in vitro model, the study also examined the impact of vegetable addition on the oxidative stability of macronutrients during gastro-intestinal digestion. Adding vegetables improved the nutritional and functional attributes of the oil-free breads. However, they demonstrated a lower antioxidant potential compared to their oil-containing counterparts. Similarly, the textural and storage properties of the oil-free vegetable breads were poorer compared to the oil-containing breads. As expected, in the absence of oil the oil-free breads were associated with lower lipid oxidation both in their fresh form and during gastro-intestinal digestion. Adding vegetables reduced protein oxidation in the fresh oil-free breads but had no effect during gastro-intestinal digestion. The impact of vegetables on macronutrient oxidation in the oil-free breads during digestion appears to be vegetable-specific with broccoli exacerbating it and the others having no effect. Of the evaluated vegetables, beetroot showed the most promising nutritional and physico-chemical benefits when incorporated into bread that does not contain added oil.

15.
J Food Sci Technol ; 52(12): 7914-23, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26604363

RESUMO

Mayonnaise was supplemented with vegetables (5 % w/w) and the effect of storage time at 4 °C on the oxidative stability of the dispersed phase was investigated. Results indicated that mayonnaise is prone to lipid oxidation during storage under refrigerator conditions. The type of vegetable used for mayonnaise reformulation was critical in inhibiting oxidation and followed the order beetroot > carrot ≈ onion with respect to antioxidant capacity. Broccoli induced a pro-oxidant effect and the rate of oxidation by the end of the storage period was 42 times higher compared with the control. The addition of beetroot, either fresh or freeze-dried, improved the oxidative stability of mayonnaise significantly. The process of freeze-drying affected adversely the ability of vegetables to decrease oil oxidation of the emulsions. This may reflect loss of important natural antioxidants during the drying procedure.

16.
Plant Foods Hum Nutr ; 70(3): 304-9, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26142888

RESUMO

The present study investigated the impact of heat treatments on the denaturation and oxidative stability of hemp seed protein during simulated gastrointestinal digestion (GID). Heat-denatured hemp protein isolate (HPI) solutions were prepared by heating HPI (2 mg/ml, pH 6.8) to 40, 60, 80 and 100 °C for 10 min. Heat-induced denaturation of the protein isolates was monitored by polyacrylamide gel electrophoresis. Heating HPI at temperatures above 80 °C significantly reduced solubility and led to the formation of large protein aggregates. The isolates were then subjected to in vitro GID and the oxidative stability of the generated peptides was investigated. Heating did not significantly affect the formation of oxidation products during GID. The results suggest that heat treatments should ideally remain below 80 °C if heat stability and solubility of HPI are to be preserved.


Assuntos
Cannabis/química , Proteínas Alimentares/metabolismo , Temperatura Alta , Proteínas de Plantas/metabolismo , Desnaturação Proteica , Sementes/química , Digestão , Eletroforese em Gel de Poliacrilamida , Trato Gastrointestinal , Humanos , Técnicas In Vitro , Oxirredução , Peptídeos/metabolismo , Solubilidade , Soluções
17.
Food Sci Nutr ; 2(6): 802-10, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25493199

RESUMO

The demand for products of high nutritional value from sustainable sources is growing rapidly in the global food market. In this study, the effect of pH on the functional properties of lupin, green pea, fava bean, hemp, and buckwheat flours was investigated and compared with wheat flour. Functional properties included solubility, emulsifying and foaming properties, gelling ability, and water holding capacity (WHC). All flours had minimal solubility at pH 4 and their corresponding values increased with increasing pH. Emulsifying properties were improved at pH 10 for all samples and emulsion stability showed a similar trend. Increasing pH in the range 4-10 enhanced the foaming properties of the flours, particularly buckwheat and hemp. Wheat, green pea, buckwheat, and fava bean were more capable of forming firm gels compared with lupin and hemp, as indicated by least gelling concentrations (LGCs). The ranking of the water binding properties of the different types of flours were lupin>hemp>fava bean>buckwheat>green pea>wheat. Results indicate that underutilized flours from sustainable plant sources could be exploited by the food industry as functional food ingredients or as replacements of wheat flour for various food applications. Depending on the application, flour functionality may be effectively tailored by pH adjustment.

18.
Dairy Sci Technol ; 94: 91-101, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24511365

RESUMO

Milk proteins have attracted extensive interest in terms of their bioavailability following ingestion. Enzymatic digestion of dairy products generates numerous peptides with various biological activities. Both human milk and infant formulas based on cow's milk are potential sources of bioactive peptides. This review aims to present current knowledge on the formation and fate of bioactive peptides from milk feeds intended for infants. Emphasis is placed on the source of the bioactive peptides with the nutritional impact of human milk and cow milk-based formulas on infant health being critically discussed from that perspective. Furthermore, the effect of processing and in vitro or in vivo digestion on the release and availability of peptides with bioactive sequences is evaluated. Considerable differences with respect to bioavailability and metabolic effects between the biologically active fragments generated following ingestion of human milk and infant formulas are documented. Peptides from milk protein of bovine origin could be a valuable supplement to human milk as multiple health-promoting properties are attributed to peptide fractions identified in standard cow milk-based infant formulas.

19.
J Chromatogr A ; 1305: 221-9, 2013 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-23899382

RESUMO

Milk proteins are able to facilitate the formation and stabilization of oil droplets in food emulsions. This study employed Sedimentation Field-Flow Fractionation (SdFFF) to monitor changes in particle size distribution of freshly prepared emulsions with varying weight contributions of sodium caseinate (SC) and whey protein concentrate (WPC). The effect of the addition of Tween 80 (T) on the initial droplet size was also investigated. The results indicated that emulsifying ability follows the order Tween 80>WPC>SC, with corresponding weight average droplet diameter of 0.319, 0.487 and 0.531µm respectively, when each of the above emulsifiers was used solely. The stability of sodium caseinate emulsions was studied at 30.5 and 80.0°C by measuring the particle size distribution for a period of 70h. Emulsions withstood the temperatures and exhibited an initial increase in particle size distribution caused by heat-induced droplet aggregation, followed by a decrease to approximately the initial droplet size. The rate of droplet aggregation depends on the severity of thermal processing, as revealed by the kinetics of particle aggregation during aging at different temperatures. Comparison of the experimental rate constants found from SdFFF, with those determined theoretically gives invaluable information about the oil droplet stability and the aggregation mechanism. Based on the proposed mechanistic scheme various physicochemical quantities, which are very important in explaining the stability of oil-in-water emulsions, were determined. Finally, the advantages of SdFFF in studying the aggregation of the oil-in-water droplets, in comparison with other methods used for the same purpose, are discussed.


Assuntos
Emulsões , Fracionamento por Campo e Fluxo , Proteínas do Leite/química , Tensoativos/química , Cinética , Microscopia Eletrônica de Varredura , Óleos/química , Tamanho da Partícula , Água/química
20.
Nahrung ; 47(6): 369-76, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14727762

RESUMO

Egg-white proteins are extensively utilised as food ingredients due to their unique functional properties. Several attempts have been made in order to improve the functional properties of egg-white proteins and to identify the optimal formulations for unique food products. Experimental data proves that controlled denaturation of egg-white proteins can have a beneficial impact on various functional applications in the food industry such as emulsifying ability, heat stability, and gelation. This review describes the effect of heat-induced denaturation on protein structure and functionality. Studies on the impact of Maillard reaction, which aim to elucidate the structure-function relationship of egg-white proteins, are presented. A novel approach which could be the basis for the development of new methods aiming to improve the functional properties of egg-white proteins is also discussed.


Assuntos
Proteínas do Ovo/química , Proteínas do Ovo/fisiologia , Géis , Temperatura Alta , Reação de Maillard , Dobramento de Proteína , Solubilidade , Relação Estrutura-Atividade
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