盐生植物碱蓬制备膳食纤维的工艺优化研究

以盐生植物碱蓬提取叶蛋白后的残渣为原料,采用酶解处理和碱处理相结合的方法,研究得到了碱蓬高活性膳食纤维的最佳提取工艺。所得碱蓬膳食纤维的膨胀力达9.7mL/g,持水力达515%,其功能性质优于小麦麸皮膳食纤维。     

山东碱蓬属两种植物形态解剖学研究

目的鉴别比较山东碱蓬及盐地碱蓬的外部形态与其内部解剖构造。方法采用常规显微制片法,在解剖镜与光学显微镜下观察比较碱蓬及盐地碱蓬。结果碱蓬和盐地碱蓬在外部形态、叶表皮微形态、叶横切面、茎横切面解剖构造等方面存在差异。结论本研究为碱蓬和盐地碱蓬的鉴别及开发利用提供了参考。     

响应面优化提取灰绿碱蓬多糖及脱色工艺研究

应用响应面法在单因素试验基础上对灰绿碱蓬多糖提取条件进行优化,测定了灰绿碱蓬根、茎、叶的基本营养物质成分,并对多糖脱色工艺进行探究。乙醇体积分数65%、提取时间72min、超声功率438 W,提取温度85℃为最佳提取参数,此时碱蓬多糖提取得率达到2.19%±0.13%。选择HZ-800大孔树脂作为碱蓬多糖的脱色方式,添加量为1.8%,脱色率为95.51%,多糖保留率为79.62%,此时脱色效果和多糖保留率最好。     

碱热法分离制备红菇娘籽蛋白的工艺研究

研究了碱热法分离制备红菇娘籽蛋白的工艺条件,并用微量凯氏定氮法测定蛋白质含量。碱热法提取蛋白质是利用蛋白质在强碱作用下能絮凝沉降的性质,把pH调至强碱性,使蛋白质产生最佳的絮凝效果。在单因素实验的基础上,以絮凝温度、絮凝时间、提取液pH值3因素进行正交实验,确定出红菇娘籽蛋白的最佳分离制备条件为:絮凝温度40℃、絮凝时间50 min、pH值11,粗蛋白的提取率为46.91%。粗蛋白中17种氨基酸种类齐全,含量丰富。     

四翅滨藜叶蛋白提取工艺优化及氨基酸分析

对四翅滨藜叶蛋白的提取工艺及氨基酸分析进行研究,确定最佳工艺条件为:料液比1:20,预浸48 h,打浆时间4 min,pH=3.0,60℃条件下絮凝5 min.此时叶蛋白提取率和收率分别可达31.05%和1.12%.氨基酸分析结果显示,四翅滨藜叶蛋白的氨基酸组成种类齐全,必需氨基酸含量较高,氨基酸分数较高,是一类比较优质的蛋白质资源.     

苜蓿干草中提取叶蛋白最佳工艺的研究

采用酸化加热加盐的综合方法提取苜蓿干草中的叶蛋白,分别进行了草粉预浸时间、絮凝时间、絮凝温度、料水比、加盐量和提取液pH等6个因素对叶蛋白粗蛋白提取率影响的单因素实验研究,得到各单因素最佳工艺参数分别为:预浸时间24h,絮凝时间10min,料水比1∶30,絮凝温度60℃,pH3,加盐量2%。对料水比、加盐量、絮凝时间和pH的四因素三水平正交实验结果表明,影响粗蛋白提取率的因素依次为料水比>加盐量>pH>絮凝时间,最佳工艺条件组合为料水比1∶20,加盐量1%,絮凝时间5min和pH为2.5。     

超声波辅助提取翅碱蓬籽油脂的工艺优化

以翅碱蓬籽(100目)为原料,采用超声波辅助石油醚(60～90℃)提取翅碱蓬籽油。以提取率为指标,研究超声波功率、料液比、提取时间对提取率的影响。通过正交试验和响应面试验分别对提取工艺进行优化,结果表明,采用正交法得到的最佳工艺条件为:超声波功率360 W、液料比8︰1 (mL/g)、提取时间30 min。采用响应面法得到的最佳工艺条件为:超声波功率365 W、液料比8︰1 (mL/g)、提取时间30 min。对2种优化结果进行双样本t检验,证明2种优化方法差异不显著,优化后的翅碱蓬籽油提取率平均值为22.48%。对制备的油脂进行各理化指标检测,结果显示超声波辅助提取翅碱蓬籽油脂品质符合食用植物油国家标准。     

碱蓬草总生物碱提取工艺优化及其对高脂饮食小鼠的体内抗氧化活性

目的:优化碱蓬草总生物碱的提取工艺,研究碱蓬草总生物碱对高脂饮食小鼠的体内抗氧化性。方法:以碱蓬草总生物碱的提取量作为指标,在单因素实验的基础上,进行正交分析。利用碱蓬草的总生物碱对高脂饮食小鼠进行灌胃,定期监测小鼠的衰老指标。结果:碱蓬草总生物碱的最佳提取工艺:超声时间20 min、超声温度45 ℃、乙醇浓度85%、料液比1:10,在此条件下,总生物碱的提取量为（0.65 ± 0.02）mg/g。抗氧化活性实验表明,碱蓬草总生物碱的低（2 mg/kg）、中（4 mg/kg）、高剂量（8 mg/kg）组均可以显著降低小鼠肝脏中MDA的含量（P<0.05）,同时碱蓬草总生物碱的低、中、高剂量组均可以显著增加肝脏中的CAT和GSH-Px（P<0.05）。结论:本实验的优化工艺具有良好的可行性,碱蓬草总生物碱具有抗氧化活性,可作为碱蓬草食品及医药方向的研究基础。     

灰绿碱蓬植物盐提取因素的探究及工艺优化

在探究植物盐提取因素基础上应用响应面法对灰绿碱蓬植物盐提取条件进行优化,并测定灰绿碱蓬的基本营养物质成分。水分、脂肪、蛋白质含量分别为82.8%、0.319%、2.45%,总糖含量为39.6 mg/g。影响植物盐提取因素探究条件如下:碱蓬植物盐提取的选材处于营养期、粒度为150目的芽叶部位最佳;索氏提取法最优条件为料液比1∶16(g/mL),水浸提3次;酶辅助浸提法最优条件为38℃,纤维素酶500 U浸提90 min。响应面优化的植物盐提取条件如下:料液比1∶20(g/mL)、纤维素酶600 U、浸提时间120 min、原料粒度200目,此条件下的植物盐提取平均得率为(10.31±0.27)mg/g。     

超声波-微波协同辅助提取碱蓬多糖及抗氧化性分析

以盐地碱蓬为原料,采用超声波-微波协同法提取盐地碱蓬茎叶中多糖,对多糖的提取工艺进行分析优化,并对其抗氧化性进行分析。通过响应面法优化盐地碱蓬茎叶中多糖的最佳提取工艺为:料液比0.51 ∶ 80(g/mL)、超声功率366 W、提取时间21 min、提取温度70℃。在此条件下多糖得率为(10.714±0.720)%。体外试验表明,盐地碱蓬多糖对羟基自由基、DPPH·和O2-·均有明显的清除作用,多糖浓度5.1 mg/mL时,对羟基自由基、DPPH·和O2-·的清除率分别为89.2%、81.9%、79.2%,说明所提取的盐地碱蓬多糖具有较好的抗氧化活性。     

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.     

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。     

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。