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ABSTRACT: Ultrafiltration is widely used to concentrate proteins, but fractionation of one protein from another is much less common. This study examined the use of positively charged membranes to increase the selectivity of ultrafiltration and allow the fractionation of proteins from cheese whey. By adding a positive charge to ultrafiltration membranes, and adjusting the solution pH, it was possible to permeate proteins having little or no charge, such as glycomacropeptide, and retain proteins having a positive charge. Placing a charge on the membrane increased the selectivity by over 600% compared to using an uncharged membrane. The data were fit using the stagnant film model that relates the observed sieving coefficient to membrane parameters such as the flux, mass transfer coefficient, and membrane Peclet number. The model was a useful tool for data analysis and for the scale up of membrane separations for whey protein fractionation. 相似文献
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乳清蛋白在无添加剂酸奶中的应用 总被引:1,自引:0,他引:1
本实验采用乳清蛋白制备了一种不添加稳定剂的酸奶,为制作无添加剂酸奶提供理论依据。通过分析不同添加量的乳清蛋白对酸奶发酵终点,以及后熟和保质期内酸奶的酸度、粘度、脱水收缩作用敏感性(STS)、持水率(WHC)的影响,结果发现:乳清蛋白对发酵终点的影响不大;随着乳清蛋白添加量的增加,在后熟时酸奶的酸度变化加快;乳清蛋白可以提高酸奶在保质期内的稳定性,对STS和WHC都有促进作用,可保证产品最终质量。此外,结合感官测评,乳清蛋白添加量在3~4%时,产品口感及稳定性较佳,通过使用乳清蛋白可以使无添加剂的酸奶在保质期内稳定。 相似文献
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Turbidity and Protein Aggregation in Whey Protein Beverages 总被引:1,自引:0,他引:1
ABSTRACT: During storage of heat-treated acidic (pH ≤ 4.6) whey protein beverages, formation of protein aggregates can create undesirable turbidity and sedimentation. In this study, we found that a slow protein aggregation process controlled the rate of formation of sediment and turbidity. A heat-treated model beverage containing 12.5 g/L whey protein at a pH of 4 was stored for 6 wk at 3 different storage temperatures and analyzed for turbidity, soluble protein, and protein aggregates. One sample was stored without further treatment and the other sample was filtered to remove protein aggregates formed during heating. This was done to test the hypothesis that aggregates formed during heat treatment served as nuclei for deposition of soluble protein. Turbidity increased and soluble protein decreased as protein aggregates formed during storage. Increasing the storage temperature accelerated this process. The loss of soluble protein during storage was fit to first- and second-order kinetic equations, allowing the prediction of the effect of protein concentration, storage time, and storage temperature on the formation of protein aggregates. 相似文献
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用乳清浓缩蛋白WPC80 为原料,在复合酶A 的作用下,研究乳清肽的制备工艺。复合酶A 的反应条件为[S]12g/100mL、温度50℃、[E]/[S]3%、pH9.0。选用截留分子质量10kD 的磺化聚砜膜,常温并在工作压差0.25MPa 下对水解液进行超滤处理后,选用树脂HZ00x 对水解液进行脱苦,得到的处理液无明显的苦涩味,只有轻微的蛋腥味,最后肽得率36.54%。产品中肽的分子质量分布以二、三和四肽为主,分别占峰面积的27.45%、34.88% 和26.65%。 相似文献
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乳清蛋白的组成及其主要保健功能 总被引:7,自引:0,他引:7
乳清蛋白氨基酸组成合理、消化吸收率高,同时在消化过程中产生多种生物活性多肽,具有增强体质、提高免疫力、抗疲劳、抗氧化、抑菌抗病毒、降血脂、降血压、降血糖、抗癌等多种保健功能。本文就乳清蛋白的组成成分及其保健功能进行了综述。 相似文献
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ABSTRACT: Cation exchange was used to recover whey protein isolate (WPI) from sweet whey, and the effluent was fed to an anion exchanger to recover glycomacropeptide (GMP). Nearly all of the major whey proteins (α-lactalbu-min, β-lactoglobulin, immunoglobulin G, and serum albumin) and about half of the total Kjeldahl nitrogen (TKN) were recovered by the cation exchanger. No GMP was recovered by the cation exchanger. The anion exchanger recovered nearly all of the GMP from the effluent of the cation exchanger, accounting for about half of the remaining TKN. This process is the first to simultaneously manufacture WPI and GMP from a single stream of whey, increasing the value obtained from whey. 相似文献
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乳清蛋白酶的改性研究 总被引:1,自引:0,他引:1
乳清蛋白通过改性,可以加强其功能性质,从而合理利用资源,开发新产品,扩大在食品中的应用。乳清蛋白的改性方法有化学改性、物理改性和酶改性。酶改性主要包括水解和交联。其中,用转谷氨酰胺酶改性具有比较大的发展潜力。 相似文献
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乳清制品及其在肉制品中的应用 总被引:2,自引:0,他引:2
乳清制品作为优质的蛋白质来源受到人们的广泛关注,文中就乳清蛋白的主要生产工艺及其营养功能应用进行了分析探讨,并针对其在肉制品方面的特性进行了阐述。以国外肉制品生产企业应用乳清蛋白的典型产品为例,进一步阐述了目前乳清蛋白在我国肉制品行业应用的可行性和必然性 相似文献
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The effects of temperature, relative humidity (%RH) and permeant concentration on aroma permeability were investigated in edible whey protein isolate (WPI) films. An orthogonal regression was performed to ascertain significance of these factors. Temperature and %RH had exponential effects on d-limonene permeability, interacting synergistically to influence aroma transport in WPI polymer films. Permeability of d-limonene in WPI polymer films was not influenced by permeant concentration in the range 62 to 226 ppm (mol/mol). The predictive equation generated by regression analysis could be potentially useful for edible packaging design within the given temperature, %RH, and concentration ranges. The Arrhenius-type format also provided insight into the temperature-sensitivity of WPI films and confirmation of the influence of %RH on permeability activation energy. 相似文献
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为了进一步研究蛋白质氧化对乳清分离蛋白(WPI)功能性质及流变学性质的影响,试验采用两种不同浓度的氧化系统H2O2(1 mmoL/L~20 mmoL/L)和FeCl3浓度(0.1 mmoL/L~2 mmoL/L)对WPI分别氧化1 h、3 h、5 h,测定其性质。结果表明:20 mmoL/L的H2O2氧化WPI 5 h,其乳化活性下降了50%以上;1 mmoL/L FeCl3氧化WPI 3 h,其凝胶硬度降低了94.5%;20 mmoL/L H2O2与1mmoL/L FeCl3氧化WPI 3 h,其弹性从0.976下降到0.713和0.721,分别降低了26.9%和26.1%;当H2O2浓度20 mmoL/L时,弹性模量从8154 Pa降到5399 Pa,复合模量从10890 Pa降到6653 Pa,分别降低了33.79%和38.91%;当FeCl3浓度为1 mmoL/L时,弹性模量从8154 Pa降到4935 Pa,复合模量从10890 Pa降到6049 Pa,分别降低了39.47%和44.45%。长时间高浓度的氧化条件使得蛋白质的空间结构受到严重影响,WPI的功能性质及凝胶质地发生较大的变化。因此,在实际生产中应尽可能地控制蛋白氧化的发生,减少其因为氧化所带来的营养损失或者降低其应用价值。 相似文献
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The ability of whey protein concentrates (WPC) to form highly expanded and stable foams is critical for food applications such as whipped toppings and meringue-type products. The foaming properties were studied on six experimental and three commercial WPC, manufactured by membrane fractionation processes to contain reduced lipids and calcium. Lipid-reduced WPC had excellent foaming properties. Experimental delipidized WPC MF 0.45 and commercial delipidized WPC E had higher (P < 0.05) foam expansion than egg white protein (EWP). However. WPC B made bv low-pH UF and isoelectric orecinitation did not form a foam. Lipids and ash were the main factors affecting foaming properties. 相似文献
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Microencapsulating Properties of Whey Protein Concentrate 75 总被引:3,自引:0,他引:3
ABSTRACT Emulsions containing various levels of soya oil dispersed in solutions of whey protein concentrate (WPC) 75 (5% w/v) were spray-dried to yield powders with oil contents ranging from 20% to 75% (w/w). The effect of homogenizing pressure and oil/protein ratio on oil globule size distributions and protein load of the emulsions and the microencapsulation efficiency (ME) and redispersion behavior of the powders were examined. Emulsion oil droplet size decreased with increasing homogenization pressure but was not affected by oil/protein ratio. Emulsion protein load and ME of the powders were negatively correlated with increasing oil/protein ratio. Powders with an oil/protein ratio < 0.75 were least susceptible to destabilization during spray-drying. 相似文献