醇法大豆浓缩蛋白提取工艺的优化

采用乙醇浸出工艺生产醇法大豆浓缩蛋白,实验研究考察了乙醇浓度、浸出温度、浸出时间、固液比等因素对蛋白质含量的影响。通过正交实验,选择的最佳工艺条件为:乙醇浓度65%、固液比1∶7、浸提温度40℃、浸提时间80min。     

乙醇浸提法制备菜籽浓缩蛋白的工艺研究

本实验采用乙醇浸提法制备菜籽浓缩蛋白,在单因素试验的基础上,采用L9(34)正交优化试验,探讨乙醇浓度、浸提温度、浸提次数和料液比对浓缩蛋白产品蛋白含量的影响。单因素试验结果表明,最佳浸提工艺参数分别为：乙醇浓度70%、浸提温度60℃、浸提次数5 次,料液比1:7、每次浸提25min。正交试验结果表明：影响蛋白含量的主要因素为乙醇浓度,其次为浸提温度、料液比、浸提次数。最佳浸提工艺条件为A3B2C2D2,即乙醇浓度70%、浸提温度55℃、料液比1:6,浸提次数5 次。在此条件下制备的浓缩蛋白产品蛋白含量为60.5%,浓缩蛋白得率为75.7%,浓缩蛋白产品中抗营养因子成分——单宁、植酸、硫甙分别被脱除90.5%、66.7%、99.3%。     

醇法提取大豆浓缩蛋白凝胶性能的优化

采用乙醇浸出工艺生产醇法大豆浓缩蛋白，研究乙醇浓度、浸出温度、浸出时间、固液比等因素对蛋白质凝胶性的影响。通过正交试验，选择最佳提取工艺条件为：乙醇浓度印％、固液比1：6、浸提温度40℃、浸提时间70min。在此条件下。蛋白质含量为65．23％、凝胶性为3987cp。     

多级逆流醇浸法制取大豆浓缩蛋白工艺的研究

大豆浓缩蛋白具有比脱脂蛋白粉蛋白质含量高和比大豆分离蛋白价格低的优势,广泛应用于各种食品体系中.目前,世界上大豆浓缩蛋白的生产方法主要是乙醇浸洗法,本文采用多级逆流醇浸法,对影响大豆浓缩蛋白的工艺条件,如浸取温度、料溶比、乙醇溶液的浓度和浸取时间进行了较为详尽的研究.通过正交实验及结果分析,确定了其最佳的工艺条件为为:浸取温度60℃,料溶比1:5,乙醇溶液浓度60%,浸取时间30min.     

醇法大豆浓缩蛋白制取工艺的探讨

采用稀浓乙醇两次浸出 ,一次脱溶的工艺生产醇法大豆浓缩蛋白 ;实验研究考察了乙醇浓度、浸出温度、浸出时间、固液比对产品质量的影响。通过正交实验 ,选择的最佳生产工艺条件为 :乙醇浓度 75 %、浸出温度 30℃、浸出时间 6 0min、固液比 1∶5。二次浸出工艺条件为 :乙醇浓度90 %、浸出温度 5 0℃、工作时间 30min、固液比 1∶5。     

加工条件对醇法大豆浓缩蛋白溶解性及结构的影响

为探究工业化生产的醇法大豆浓缩蛋白溶解性较差的原因，研究了醇法加工条件(乙醇体积分数、浸提温度、干燥温度)对大豆浓缩蛋白溶解性及结构的影响。结果表明：大豆浓缩蛋白的溶解度随着乙醇体积分数的增大呈现先降低后升高的趋势，乙醇体积分数为65%时溶解度最低；浸提温度和干燥温度的升高会导致溶解度大幅降低；随着浸提液中乙醇体积分数的增大，大豆浓缩蛋白表面疏水性、分子间的疏水相互作用、二硫键含量及粒径均呈现先增加后降低的趋势，在乙醇体积分数为65%时最大，而α-螺旋含量增加，β-折叠含量整体先增加后降低，无规卷曲含量降低；随着浸提温度和干燥温度的升高，大豆浓缩蛋白分子间氢键作用力降低，而表面疏水性、分子间疏水相互作用、二硫键含量和粒径增大，α-螺旋向β-折叠及无规卷曲转变，蛋白质结构趋于无序。综上，工业化醇法加工工艺(60%～70%乙醇体积分数、50～60℃浸提温度、60～70℃干燥温度)所引发的大豆浓缩蛋白表面疏水性的增大、分子间聚集程度的增加等导致了其溶解度的降低，不利于后期应用。     

乙醇浸提法制备亚麻籽浓缩蛋白工艺研究

以冷榨亚麻籽饼为原料,采用乙醇浸提法制备亚麻籽浓缩蛋白。采用单因素试验研究了浸提工艺参数(浸提温度、浸提时间、乙醇体积分数、液固比以及浸提次数)对产品蛋白质含量的影响。在单因素试验基础上,采用正交试验进行工艺参数优化。结果表明,在所考察的范围内,各因素影响的主次顺序为乙醇体积分数浸提时间浸提温度液固比;最优工艺条件为浸提温度50℃、浸提时间75 min、乙醇体积分数70%、液固比6∶1、浸提次数2次,在此条件下亚麻籽浓缩蛋白的回收率为63. 87%,蛋白质含量为65. 38%。     

响应面法优化提高花生浓缩蛋白中蛋白干基含量的工艺研究

本文研究了响应面法优化提高花生浓缩蛋白中蛋白干基含量的工艺方法。花生浓缩蛋白经由乙醇沉淀和物理沉降的方法从脱脂花生蛋白粉中制得。通过响应面优化的方法研究了提取过程中,料液比、乙醇浓度和浸提温度对花生浓缩蛋白干基含量的影响。结果表明：回归模型决定系数较高,最佳提取工艺条件为第一次浸提料液比1：11．34（w／v）、乙醇浓度74．47％、浸提温度46．36℃;第二次浸提料液比1：10（w／v）、乙醇浓度80％、浸提温度25℃。     

醇法菜籽浓缩蛋白提取工艺研究

以菜籽粕为原料,对乙醇法制取菜籽浓缩蛋白进行了研究.分别考察了浸提温度、浸提次数、乙醇体积分数和溶剂比对菜籽浓缩蛋白蛋白含量的影响.由单因素试验和正交试验得出醇法菜籽浓缩蛋白的最佳浸提条件为:浸提温度60℃,浸提次数6次,乙醇体积分数80%,溶剂比9:1,pH4.0.在此条件下所得菜籽浓缩蛋白的蛋白含量为65.96%,提取率为71.54%.     

木瓜蛋白酶提高醇法大豆浓缩蛋白乳化性的研究

制取低成本、高蛋白含量的大豆浓缩蛋白时,乙醇产生变性作用,从而降低了大豆浓缩蛋白的功能特性,因此本研究采用木瓜蛋白酶对醇法大豆浓缩蛋白进行改性。通过对酶浓度、底物浓度、改性时间与改性温度的单因素实验,针对乳化性进行研究,然后进行正交试验,最终得出木瓜蛋白酶提高醇法大豆浓缩蛋白乳化性最佳工艺条件:酶用量(E/S)为3%、底物浓度为(W/V)8%、改性时间为2h、改性温度为50℃,改性中pH值为6.0,可提高乳化能力3.8倍,乳化稳定性3.9倍。     

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.     

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.     

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。     

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...     

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.     

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。     

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。     

几种新型花生蛋白产品的生产

本文从花生蛋白质利用的角度介绍了几种新型花生蛋白产品的加工工艺，针对我国人民膳食结构中蛋白质的摄入水平较低的实际情况，论述了花生蛋白开发利用的必要性，展望了花生蛋白开发利用的广阔前景。