燕麦蛋白组分分离提取及其SDS-PAGE电泳分析

通过单因素实验对燕麦蛋白组分的分离提取工艺进行了优化,并通过SDS-PAGE电泳对燕麦蛋白组分进行亚基分析。结果表明:燕麦清蛋白提取的最佳温度为40℃,球蛋白提取最佳盐浓度为7%,醇溶蛋白提取的最佳乙醇浓度为75%,谷蛋白提取的最佳碱浓度为0.05 mol/L,蛋白质提取率为83.1%。SDS-PAGE实验结果显示:燕麦清蛋白在10~100 kD范围内均有分布,燕麦球蛋白由2个亚基组成,分子量分别在97.4~100 kD和43~66.2 kD范围内,燕麦醇溶蛋白亚基大部分集中在18.39~40.72kD之间,燕麦谷蛋白部分亚基分布在20.67~26.66kD与43.29~50.80 kD之间。     

大红袍花椒籽种仁蛋白的分类研究

对大红袍花椒种仁蛋白质进行了Osborne蛋白质分类,分离出花椒种仁清蛋白16.38%、球蛋白41.09%、醇溶蛋白2.53%、谷蛋白33.29%,然后将分类后的各种花椒种仁蛋白质进行SDS-PAGE电泳分析测定亚基大小.结果表明,蛋白质组分中含有大量盐溶性的球蛋白和碱溶性的谷蛋白,易采用盐溶法或稀碱提取;并且花椒种仁中各蛋白质组分的相对分子质量较小,有利于人体对蛋白质的消化吸收.     

棉籽分离蛋白制备工艺研究

以脱脂棉籽粕为原料,采用碱溶酸沉法制备棉籽分离蛋白。以蛋白质提取率、产品蛋白质含量为指标,考察提取温度、提取时间、p H、液固比对棉籽分离蛋白提取效果的影响。另外,采用SDS-PAGE对所制备棉籽分离蛋白中蛋白质亚基相对分子质量分布进行了分析。结果表明,通过正交实验优化得到棉籽分离蛋白最佳制备工艺条件为:提取温度60℃,提取时间60 min,p H 10,液固比14∶1。在最佳工艺条件下,蛋白质提取率为73.21%,产品蛋白质含量为90.76%(N×6.25,干基),且游离棉酚含量由原料的0.12%下降到0.033%。棉籽分离蛋白中蛋白质亚基相对分子质量主要为59.3 k Da与53.7 k Da,占47.66%。     

樱桃仁蛋白的提取

对樱桃仁蛋白的提取方法进行了研究,采用碱溶酸沉法提取樱桃仁中的蛋白质并测定其等电点,使用SDS-PAGE法测定了樱桃仁蛋白的亚基组成及其分子量.结果表明,樱桃仁蛋白的等电点为3.72,优化后的提取条件是pH值为9.5,浸提时间为40min,温度为40℃,料液比1∶15,樱桃仁蛋白中含有7种亚基,其中分子量为18 694的亚基含量最高,为41.8%.     

大黄鱼鱼卵蛋白组分提取及其功能特性研究

试验采用Osborne方法提取了大黄鱼脱脂鱼卵中的水溶蛋白、盐溶蛋白、醇溶蛋白和碱溶蛋白,并对其进行功能性质评价,通过聚丙烯酰胺凝胶电泳法进一步研究了各蛋白组分的亚基组成与分子量分布。结果表明:水溶蛋白是大黄鱼脱脂鱼卵蛋白的主要组分,占脱脂鱼卵总蛋白含量的44.6%。碱溶蛋白持水性,醇溶蛋白持油性较好,水溶蛋白的溶解性较好,水溶蛋白和碱溶蛋白的起泡性较好,4种蛋白在碱性条件下乳化性均较好。     

葡萄籽蛋白质的提取工艺研究

测定了葡萄籽蛋白质的等电点并分别研究了盐溶法和碱溶法提取葡萄籽蛋白质的工艺条件.研究结果表明:葡萄籽蛋白质的等电点为pI=3.8;碱溶法蛋白质提取率高于盐溶法,碱溶法提取蛋白质的最优工艺条件是以1×10-5 mol/L浓度的NaOH溶液,按1:15的料液比,在40℃条件下搅拌浸提40 min,在此条件下葡萄籽蛋白质的提取率达73.78%.     

豌豆分离蛋白提取工艺的研究

主要研究了采用碱溶酸沉法提取豌豆分离蛋白的各个影响因素,同时采用超声波改进的提取工艺与传统工艺进行比较,通过实验得出传统的碱溶酸沉工艺提取豌豆分离蛋白的最佳工艺为:固液比为1∶25、pH为9.0、提取温度为45℃、提取时间为50min,在此提取条件下蛋白质的提取率为81.82%,其中蛋白质的含量为91.23%.采用超声波改进工艺后,蛋白质的提取率明显要高于传统工艺,其蛋白质的提取率可以达到83.21%.其最佳工艺为:料液比1∶15、功率为300W,时间为30min.     

小米蛋白提取、测定以及SDS-PAGE电泳

依照Osborne法对小米清蛋白、球蛋白、醇溶蛋白和谷蛋白进行分离提取,通过单因素试验确定小米蛋白提取时的最佳条件,并通过SDS-PAGE对小米蛋白组分进行了亚基分析。结果表明,小米清蛋白提取的最佳温度为40℃,球蛋白提取的最佳氯化钠质量分数为2%,醇溶蛋白提取的最佳醇体积分数为80%,谷蛋白提取的最佳氢氧化钠浓度为0.05 mol/L。小米蛋白各组分SDS-PAGE凝胶电泳图谱显示,小米清蛋白的亚基主要分布在(97.4~22)ku范围内且含有二硫键;小米球蛋白的亚基主要分布在(66.2~10)ku范围内;小米醇溶蛋白的亚基条带分布广泛且含有二硫键;小米谷蛋白的亚基条带分布在(66.2~10)ku范围内。不同提取条件不仅会影响提取率,同时也会影响蛋白组分的亚基组成。     

莲子磨皮粉中蛋白质的提取、组成及性质

采用碱溶酸沉法提取莲子磨皮粉中的蛋白质,并以莲子中提取的蛋白质作对照,采用十二烷基磺酸钠-聚丙烯酰胺凝胶电泳、体积排阻色谱法测定了两种蛋白质的组成差异,采用差示扫描量热仪及傅里叶红外光谱对两种蛋白质的部分性质和结构进行了表征。结果显示：碱溶酸沉法提取莲子磨皮粉和莲子蛋白质的提取率分别为72.24%和78.93%;凝胶电泳图谱显示,莲子磨皮粉蛋白质亚基分子质量分布在15～70 kD,而莲子蛋白质亚基分子质量分布在10～45 kD;体积排阻色谱图谱也显示莲子磨皮粉蛋白质中包含有更多的不同分子质量的蛋白质组分;差示扫描量热仪分析显示,莲子磨皮粉蛋白质的变性峰值温度为118.28 ℃,莲子蛋白质为108.05 ℃,且莲子磨皮粉蛋白质变性焓值更高,因而蛋白质空间结构有序性较高;傅里叶红外光谱分析也揭示莲子磨皮粉蛋白质相比于莲子蛋白质构象更为有序。     

高蛋白含量大麦发芽过程中蛋白质组分及其含量变化分析

本文利用SDS-PAGE电泳技术,比较分析了蛋白质含量较高的国产甘啤4号大麦和蛋白含量适中的进口质量大麦Gairdner在发芽过程中蛋白质组分及其含量变化.研究发现,高氮甘4在发芽过程中,水溶性蛋白的低分子质量蛋白分解较强烈;盐溶蛋白的中分子质量蛋白分解较多;醇溶蛋白的高、中分子质量蛋白亚基组分含量较高,而其分解效果较差;碱溶蛋白中高分子质量蛋白大量的分解为中分子质量蛋白亚基.本文基本找到了高蛋白含量大麦发芽过程中不同蛋白组分及其含量变化的规律.     

Short communication: Muscle protein synthetic response to microparticulated whey protein in middle-aged men

Whey protein concentrate (WPC) is a high-quality dairy ingredient that is often included in formulated food products designed to stimulate muscle anabolism. Whey protein concentrate can be affected by UHT processing, and its sensory properties are not compatible with some formulated food products. Microparticulated WPC (mWPC) is a novel ingredient that is resistant to heat treatment and has enhanced sensory properties. When 16 healthy middle-aged men consumed 20 g of either WPC or mWPC, both proteins increased plasma essential AA and leucine concentrations with no detectable difference in curve kinetics. Myofibrillar protein synthesis was increased in both groups for 90 min after ingestion with no difference between groups. Ingestion of mWPC resulted in a muscle anabolic response that was equivalent to that of WPC over the full 210-min measurement period. Formulated products incorporating mWPC or standard WPC would provoke equivalent anabolic responses.     

大豆蛋白溶解性研究

该文概述大豆蛋白溶解特性及其与一般物质溶解差异,介绍提高大豆蛋白溶解性改性方法及研究现状,对比不同改性增溶方法优、缺点,并提出今后大豆蛋白改性研究方向。     

Co-precipitation of whey and pea protein – indication of interactions

The aim was to optimise the yield of co-precipitation of whey protein isolate (WPI) and pea protein isolate (PPI) and compare co-precipitates and protein blends with respect to solubility. The yield of co-precipitates was tested with different protein ratios of WPI and PPI in combination with different temperatures and acid precipitation (pH 4.6). The highest precipitation yield was obtained at protein ratios WPI < PPI, high temperature and alkaline protein solvation. The solubility was measured by an instability index and absorption spectroscopy of re-suspended precipitated proteins at pH 3, 7 and 11.5. Co-precipitates had significantly lower solubility than protein blends. Protein ratios WPI > PPI, low precipitation temperature and high pH showed the highest solubility. Differences in protein composition between co-precipitates and protein blends were observed with SDS-PAGE and matrix-assisted laser desorption ionisation time-of-flight, and indicated different protein–protein interaction in samples, which needs further investigations.     

细菌中蛋白质样品制备方法研究进展

细菌在生长繁殖时,细菌蛋白的表达受到环境影响而存在较大差异,使得细菌蛋白表达具有复杂性.在食品生产加工过程中可能会受到致病菌污染,细菌产生的内毒素和外毒素均会对人体健康构成威胁,因此需要高灵敏度和高特异性的检测方法来定量分析和鉴定食品中的细菌毒素.蛋白组学方法可以揭示细菌蛋白组成及其潜在的生物学功能,感染过程中菌体蛋白...     

酶制剂在蛋白质加工行业的应用

蛋白质的加工是食品行业中发展最快的领域之一，蛋白质加工的主要用酶是蛋白质水解酶，以蛋白质加工和研究的几个热点领域，如大豆分离蛋白、米蛋白、谷朊蛋白等为例，对酶制剂在蛋白质加工中的应用进展情况进行了回顾并对未来发展进行了展望。     

The structures and functions of ice crystal-controlling proteins from bacteria

Many organisms have evolved into unique mechanisms which minimize freezing injury due to extracellular ice formation. Specifically, certain bacteria have produced a few proteins each with different functions. For example, the ice nucleation protein acts as a template for ice formation, which is responsible for imparting ice nucleating activity. The anti-nucleating protein inhibits the fluctuation of ice nucleus formation by a foreign particle in the water drop. Also, the antifreeze proteins depress the freezing temperature, modify or suppress ice crystal growth, inhibit ice recrystallization, and protect the cell membrane from cold-induced damage. In this article, a review on the current knowledge of the structure and the function of these three types of proteins, which are capable of interacting with ice itself or its nuclei from bacteria.     

大豆蛋白生产与应用现状

该文综述大豆蛋白制品—大豆蛋白粉、大豆分离蛋白、大豆浓缩蛋白、大豆组织蛋白生产现状、存在问题及大豆蛋白在面制品、肉制品、乳制品、饮料制品等中应用现状。     

Effects of silage protein degradability and fermentation acids on metabolizable protein concentration: A meta-analysis of dairy cow production experiments

A meta-analysis was conducted using data from dairy cow production studies to evaluate silage metabolizable protein (MP) concentrations. The data consisted of 397 treatment means in 130 comparisons, in which the effects of silage factors (e.g., date of harvest, wilting, silage additives) were investigated. Within a comparison, a fixed amount of the same concentrate was fed. A prerequisite of data to be included in the analysis was that silage dry matter (DM), crude protein (CP), ammonia N, lactic acid (LA), and total acid (TA) concentrations and digestibility were determined. A smaller data set (n = 248) comprised studies in which silage water-soluble N concentration was also analyzed. The supply of MP was estimated as amino acids absorbed from the small intestine using a model with constant values for ruminal effective protein degradability (EPD) and intestinal digestibility of rumen undegraded protein. Microbial protein was calculated on the basis of digestible carbohydrates and rumen degradable protein (RDP). Alternative models were used to estimate microbial protein formation, assuming the energy values of RDP and TA to be equivalent to 1.00, 0.75, 0.50, 0.25, and 0 times that of digestible carbohydrates. Because EPD values are seldom determined in production trials, they were derived using empirical models that estimate them from other feed components. The goodness of fit of models was compared on the basis of root mean squared error (RMSE) of milk protein yield (MPY) predicted from MP supply (adjusted for random study effect) and Akaike's information criterion. Metabolizable protein supply calculated from basal assumptions predicted MPY precisely within a study (RMSE = 16.2 g/d). Variable contribution of RDP to the energy supply for microbial synthesis influenced the precision of MPY prediction very little, but RMSE for MPY increased markedly when the energy supply of rumen microbes was corrected for TA concentration. Using predicted rather than constant EPD values also increased RMSE of MPY prediction. These observations do not mean that the supply of MP from undegraded feed protein is constant. However, it suggests that our current methods overestimate the range in EPD values and that the techniques have so many inherent technical problems that they can mask the true differences between the feeds. Including new elements in feed protein evaluation models may not improve the precision of production response predictions unless the consequent effects on the supply of other nutrients are taken into account.     

大豆分离蛋白改性对其功能性质影响

大豆分离蛋白是大豆蛋白最为精制形式,广泛应用于食品工业,并在不同产品中表现出不同功能。该文综述近年来大豆分离蛋白物理、化学、酶法及基因工程改性对其功能性质影响,经不同方式改性可产生合适功能性质,从而拓宽大豆分离蛋白在食品工业中应用。