Interactions of dietary fibre and omega-3-rich oil with protein in surimi gels developed with salt substitute

Most Western populations have insufficient intake of fibre and ω-3 polyunsaturated fatty acids (PUFAs), while sodium intake greatly exceeds the recommended maximum. Surimi seafood is not currently fortified with these nutraceutical ingredients. Alaska pollock surimi seafood was developed with salt substitute and fortified with either 6 g/100 g of fibre or 10 g/100 g of ω-3 oil (flax:algae:menhaden, 8:1:1) or fibre + ω-3 oil (6 g/100 g of fibre + 10 g/100 g of ω-3 oil). The objective was to determine effects of the dietary fortification on physicochemical properties of surimi. Fortification with either dietary fibre or ω-3 oil alone or in combination enhanced (P < 0.05) rheological and textural characteristics. The combined fortification had a synergistic effect on rheological properties. This indicates greater gelation of surimi in the presence of fibre + ω-3 oil, suggesting their interaction with surimi myofibrillar proteins. Fibre results in protein dehydration increasing protein concentration; while oil is immobilised by protein filling void spaces in the gel matrix. Differential scanning calorimetry showed that fibre and ω-3 oil did not interfere with normal denaturation of surimi proteins. Colour properties were only slightly affected (P < 0.05). Fortification of surimi with fibre and ω-3 oil resulted in a quality product that could be useful in developing surimi products with nutritional benefits.     

Ice Cream: Foam Formation and Stabilization—A Review

Ice cream has been studied from ingredients to process conditions, ice crystal formation to ice crystal growth, and ingredient selection to eating quality. One of the key aspects of ice cream is air cells, as formation and acceptance of ice cream rely on foam production and stabilization. Air cells in ice cream provide a unique structure that governs many of this product's keeping and eating qualities. The air cells are dependent upon ice cream mix composition (fat, protein, and surface active ingredients) as well as processing conditions (freezer shear force, hardening time, and storage temperatures). Optical, low-temperature scanning electron microscopy and transmission electron microscopy are applied to observe the morphology and size of air cells in ice cream. Air cells are crucial in forming the product and for eating quality and enjoyment.     

不同面筋蛋白组分对小麦淀粉消化特性的影响机理

分别将面筋蛋白、谷蛋白及醇溶蛋白与淀粉按一定质量比（14∶86）混合,运用流变仪、热重分析仪及激光共聚焦显微镜等手段分析不同面筋蛋白组分与淀粉/α-淀粉酶之间的相互作用,以明确面筋蛋白及其不同组分对淀粉消化特性的影响及潜在机理。结果表明：与纯小麦淀粉相比,添加面筋蛋白、谷蛋白及醇溶蛋白使酶解120 min的淀粉消化率分别下降了39.93%、49.48%及26.61%。淀粉与不同面筋蛋白组分之间通过氢键相互作用形成了更稳定的复合物,提高了样品的热稳定性。与面筋蛋白和醇溶蛋白相比,添加谷蛋白在淀粉基质周围形成了更加致密的物理性屏障,更大程度地抑制了酶对淀粉的水解。此外,谷蛋白对α-淀粉酶的抑制率最高（约79%）,激光共聚焦观察到的结果也证实了谷蛋白和α-淀粉酶之间的结合程度更高。研究结果有助于丰富典型蛋白质组分调控食品体系中淀粉消化的机理,为低血糖指数食品的开发提供一定理论指导。     

植物多酚-蛋白质复合物生物活性及应用研究进展

蛋白质与植物多酚是食品体系中的重要组成成分,其相互作用被广泛研究,这种相互作用对于合理设计功能性食品和提高多酚、蛋白质的生物利用率具有重要意义.本文主要从植物多酚与蛋白质的关系出发,阐述影响多酚与蛋白质相互作用的因素;同时重点总结近几年多酚-蛋白质复合物的抗氧化性、消化性、致敏性和抑菌性等生物活性的研究进展及其在食品医...     

胶原蛋白-葡甘聚糖-壳聚糖共混膜的物理性能和热稳定性

研究了胶原蛋白、葡甘聚糖含量等因素,对胶原蛋白-葡甘聚糖-壳聚糖共混膜(CKCS)的抗张强度、断裂伸长率和溶胀吸水率的影响,同时测定了共混膜的透水气性,并利用热重分析(TGA)法和差示量热扫描(DSC)分析法,考察了共混膜的热稳定性。为共混膜在食品材料领域的应用提供试验依据。     

Yeast viability during fermentation and sur lie ageing of a defined medium and subsequent growth of Oenococcus oeni

Interactions between the yeast strain used for primary oenological fermentation and the bacterium used to conduct subsequent malolactic fermentation were studied under model winemaking conditions. A commercial Saccharomyces cerevisiae wine yeast (strains, EC 1118, AWRI 835 and CY-3079) was grown in a defined medium whose composition approximated grape juice. Fermentations by all strains reached dryness, and retained a cell viability of greater than 90% upon completion of fermentation. Highest total viable cell number and percentage of viable cells were recorded for EC 1118. A sur lie ageing of the fermented medium over a 12 week period revealed a bi-phasic decay of culture viability for all strains. Thus 99% of cells had died within 2 weeks post-fermentation. Viabilities were then stable for the subsequent 4–6 week period before a second decline phase ensued and ended in either a minimal ( ca 100 CFU/mL, EC 1118) or no viable cells being detected at 12 weeks of ageing. The growth response of an Oenococcus oeni inoculum to yeast culture supernatants, previously aged for up to 12 weeks in the presence or absence of yeast lees, was evaluated in a bio-assay. In this way, yeast strains could be designated as being either inhibitory, neutral or stimulatory to the growth of O. oeni (strain Lc5p). Inhibition by supernatants of strain EC 1118 was evident, but found to be reduced by ageing the supernatant (with or without lees). Conversely, longer ageing on yeast lees increased the magnitude of the stimulatory response in O. oeni (strain Lc5p) to the supernatant from the wine yeast (strain CY-3079).     

Effects of the indigenous microflora of minimally processed lettuce on the survival and growth of Listeria innocua

Interactions between the natural background microflora of shredded lettuce and Listeria innocua (in lieu of Listeria monocytogenes ) were studied. The effect of increasing the initial size of indigenous populations (from 10³ to 10⁶–10⁷ CFU g⁻¹) was tested for its ability to reduce L. innocua growth on shredded lettuce. Co-culture experiments were performed in model media, where bacterial isolates from the indigenous microflora were tested for possible inhibitory effects. Varying the size of the indigenous populations had no effect on L. innocua survival or growth. However, interactions with individual species and mixed populations from lettuce did affect the survival and growth of L. innocua in model media. In general, mixed populations diminished L. innocua growth. In the undiluted lettuce medium, the various species tested individually either reduced or did not affect the growth of L. innocua . However, when the medium was diluted, some species extended the survival of L. innocua . Competition between the indigenous microflora and L. innocua resided mostly with the Enterobacter spp. and not with the pseudomonads. Enterobacter cloacae was particularly effective in reducing L. innocua growth. Lactic acid bacteria also reduced L. innocua growth in undiluted media. It is concluded that interactions with the natural background microflora may play an important role in determining the dynamics of Listeria populations on shredded lettuce.     

Microencapsulation of bioactive compounds from mulberry (Morus alba L.) leaf extracts by protein–polysaccharide interactions

Mulberry leaf extracts were generated using four concentrations of ethanol (50%, 60%, 70%, and 95% v/v). A 60% ethanolic mulberry leaf extract (60E) yielded a high total phenolic content (TPC) and antioxidant activity using 1, 1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging and a ferric reducing antioxidant power (FRAP) assay. Coating materials were derived using a combination of soy protein isolates (SPI) and low methoxyl (LM) pectin in a 1:1 ratio. The effect of various parameters on microencapsulation, such as pH (3.5, 4.0, and 4.5) and the concentration of coating materials (2.5, 5.0 and 7.5% w/v), was studied. Microcapsules produced using 60E as a core material at pH 4.0 with 7.5% of coating material showed a high encapsulation yield, encapsulation efficiency, TPC and antioxidant activity.     

Interactions between milk proteins and polyphenols: Binding mechanisms,related changes,and the future trends in the dairy industry

The biological activity and techno-functional properties of phenolic compounds have gained great importance due to the epidemiologically-proved health benefits. Use of polyphenols as fortification agents for functional food production and nanotechnological approaches using natural vehicles for polyphenol delivery have been recently discussed. In this respect, milk proteins and dairy products represent unique characteristics for polyphenol studies. The conflicting results on the functionality of polyphenols interacting with milk proteins either in model systems or in complex dairy matrices reveal the need for future studies.