Influence of ultrasonic treatment on the structure and emulsifying properties of peanut protein isolate

Effects of ultrasonic treatment on emulsifying properties and structure of peanut protein isolate (PPI) were evaluated by analysis of particle size distribution, protein surface hydrophobicity, SDS-PAGE, circular dichroism spectra and environmental scanning electron microscopy. The emulsifying properties of the PPI were found to be improved by ultrasonic treatment. The mean particle size decreased from 474.7 nm to 255.8 nm while the molecular weight remained unaffected. The results of intrinsic fluorescence spectroscopy and surface hydrophobicity indicated that ultrasonic treatment induced tertiary structural changes of the proteins in PPI. Emulsifying activity index and emulsion stability index were found to be correlated fairly well with surface hydrophobicity (H₀) (r = 0.712 and r = 0.668, respectively).     

大果沙棘果渣黄酮对HT29肿瘤细胞活性抑制及DNA损伤作用研究

目的:研究大果沙棘果渣黄酮(Seabuckthorn residue flavonoids,SRF)对人结肠癌HT29细胞生长抑制和DNA损伤的作用。方法:利用MTT比色法测定大果沙棘果渣黄酮对HT29结肠癌细胞生长的抑制率;用单细胞凝胶电泳技术(SCGE)观察大果沙棘果渣黄酮对HT29细胞DNA的损伤情况。结果:大果沙棘果渣黄酮在浓度20～200mg/L时对结肠癌细胞有明显的抑制作用,作用72h最大抑制率为81.28%;单细胞凝胶电泳显示大果沙棘果渣黄酮作用细胞48h后可见明显的彗星状拖尾。结论:大果沙棘果渣黄酮可抑制HT29细胞的生长,对其DNA有致损效应。     

溶剂法提取紫花苜蓿籽油

以盐生植物紫花苜蓿籽为原料,采用两种有机溶剂—无水乙醚和正己烷对紫花苜蓿籽进行提油的工艺研究。通过正交试验确定了正己烷为最佳提取溶剂,最佳条件为提取温度90℃,提取时间4h,料液比1∶16,此条件下的出油率为11.68%。提出的籽油中含有亚油酸15.75%,油酸12.45%,亚麻酸12.20%,硬脂酸20.52%和棕榈酸10.83%。本研究又对苜蓿籽油的理化性质进行了研究,结果表明,溶剂法浸提紫花苜蓿籽油工艺可行,产品对人体具有较高的营养保健作用。     

红豆花生饮料的研制

植物蛋白饮料营养丰富,可以作为牛奶和牛奶饮料的替代品或补充物,市场潜力巨大.以花生和红小豆为原料研制复合蛋白饮料,将红小豆在120℃下烘烤处理30 min,花生在160℃下烘烤处理20 min.试验结果表明:红小豆浆与花生浆以体积比1:1的比例混合,口感最好.添加0.06%的变性淀粉、0.05%的卡拉胶、0.15%的单甘酯和0.05%的蔗糖酯制成的饮料稳定性较好.经检测,产品各项指标均符合国家标准.     

碱溶酸沉法提纯玉米浸泡水粗蛋白的工艺优化

以玉米浸泡水粗蛋白为原料,通过单因素实验初步确定碱溶酸沉法提纯玉米浸泡水粗蛋白的条件。在单N素基础上选取影响蛋白质提纯效果明显的三个因素：碱溶阶段pH、浸提时间、料液比,进行响应面设计。得到了优化的提纯条件：温度45℃,碱溶阶段pH12,浸提时间20min,料液比（W：V）1：35、酸沉阶段pH5．5。在此条件下,玉米浸泡水的蛋白质含量为91．84％,提取率为70．06％。     

近红外光谱技术快速测定鹅肉新鲜度

目的：应用近红外光谱技术快速检测鹅肉的新鲜度,评价指标包括总挥发性盐基氮和pH值。方法：采集完整冷鲜鹅肉的近红外光谱（950～1 650 nm）,光谱经多种校正预处理后,采用偏最小二乘法建立鹅肉新鲜度的定量预测数学模型。结果：对于这2 种指标均采用标准常态变量结合偏最小二乘法所建立模型的预测效果最好,总挥发性盐基氮和pH值定量校正数学模型的模型决定系数分别为0.727、0.991,内部交互验证均方根误差分别为3.666、0.028。用此模型对预测集20 个样品进行预测,预测值与实测值的相关系数分别达到0.976、0.705,预测值平均偏差分别为－0.240、－0.024,预测值和实测值之间没有显著性差异（P＞0.05）。结论：近红外光谱作为一种无损快速的检测方法,可用于评价鹅肉新鲜度。     

固态发酵玉米黄粉饲料复合菌种的筛选

运用平板点种法、点种刺激圈法和多菌种固体发酵法3种主要方法,筛选发酵玉米黄粉饲料的复合菌株。结果表明,枯草芽孢杆菌（Bacillussubtilis）、凝结芽孢杆菌（Bacilluscoagulans）和地衣芽孢杆菌（Bacilluslicheniformis）3种菌株以1∶1∶1的比例混合,按5% 的接种量接入发酵培养基,发酵效果较好,于30 ℃条件下发酵120 h,玉米黄粉饲料中可溶性蛋白含量由3.78%提高到14.26%。     

黄伞菌丝体多糖提取工艺及免疫调节作用研究

在单因素试验基础上运用正交试验方法确定了黄伞菌丝体多糖最佳提取工艺,即菌丝体粉碎粒径为80目、加水量1∶15、提取时间2.5 h、提取温度80℃、提取1次,醇析多糖时使用无水乙醇、3.5倍于多糖溶液、醇析12 h;同时研究了黄伞菌丝体多糖在体外刺激小鼠脾淋巴细胞增殖作用,结果表明黄伞菌丝体多糖可以促进淋巴细胞增殖,具有体外调节免疫作用。     

近红外光谱法快速检测甜菜糖度的模型优化

目的建立起近红外光谱技术关于甜菜糖度的最佳预测模型。方法研究了Savitzky-Golay平滑处理、Savitzky-Golay导数、均值中心化、差分求导、净分析信号、去趋势校正、标准正态变量变换和多元散射校正等8种预处理方法的多方法联用处理进行光谱数据的预处理,结合光谱波段优选,建立甜菜糖度与近红外光谱的预测模型。结果在进行模型的评价时,以误差均方根(SEP)、校正标准误差(SEC)与交叉检验误差(SECV)作为评价指标。结论发现经过光谱波段优选之后,结合Savitzky-Golay平滑、Savitzky-Golay导数、去趋势校正及均值中心化进行光谱数据的预处理得到的模型效果最佳。     

Purification and identification of interacting components in a wheat starch–soy protein system

The objective of this research was to quantify the solubility, hydrophobicity and interaction characteristics of wheat–starch proteins (puroindoline, gliadin and glutenin) and protein-containing soy fractions (soy flour isolate [SFI], SFI 7S and 11S fractions, hexane-extracted textured soy flour [TVP] isolate, TVP 7S and 11S fractions, expelled, extruded soy flour [TSP] isolate, TSP 7S and11S fractions). Functional characteristics were assessed in aqueous sucrose solutions at pH 5.5 and 7.5 after heating to 25, 50, and 100 °C. Textured soy protein fractions were more soluble and had higher surface hydrophobicity profiles than their untextured counterparts. Sucrose addition decreased hydrophobicity in the textured proteins but increased it in untextured proteins. Characteristics of the isolate, as a whole, appear to be dictated by those of its 11S moiety. Dissociation constants (K_d values) for soy protein and starch-derived puroindoline were determined and indicated an extremely short association in all cases. The 11S fractions formed a complex with puroindoline in solution; however 7S fractions did not.