Evaluation of mustard (Brassica juncea) protein isolate prepared by steam injection heating for reduction of antinutritional factors

A process for the preparation of mustard protein isolate, comprising steps such as dispersion of defatted meal in 0.1 mol/l NaCl solution, incubation, extraction at alkaline pH, followed by treatment of the protein solution with activated carbon was developed. The protein, coagulated by steam injection, was subjected to separation by centrifugation, washing and spray drying. The parameters evaluated were protein yield, purity, presence of antinutritional factors and nutritional quality of proteins. The protein yield was 58-60%. The purity of the protein isolate was 95%. The hydrolysed products of glocosinolates like isothiocyanates and oxazolidine thione levels, phenolics and phytic acid levels were low in the protein isolate. The in vitro digestibility of the protein isolate was 92.4% compared to 80.6% of the meal. Chemical score of the meal and protein isolate were similar; isoleucine was the first limiting amino acid. The calculated nutritional indices, essential amino acid index, biological value, nutritional index and C-PER of protein isolate were higher compared to meal. The protein quality as indicated by amino acid profile and PDCAAS scores for 10-12-years old and adults were 100.     

Reactions of chlorogenic acid and quercetin with a soy protein isolate--influence on the in vivo food protein quality in rats

Plant phenolic compounds are known to interact with proteins producing changes in the food (e. g., biological value (BV), color, taste). Therefore, the in vivo relevance, especially, of covalent phenol-protein reactions on protein quality was studied in a rat bioassay. The rats were fed protein derivatives at a 10% protein level. Soy proteins were derivatized with chlorogenic acid and quercetin (derivatization levels: 0.056 and 0.28 mmol phenolic compound/gram protein). Analysis of nitrogen in diets, urine, and fecal samples as well as the distribution of amino acids were determined. Depending on the degree of derivatization, the rats fed with soy-protein derivatives showed an increased excretion of fecal and urinary nitrogen. As a result, true nitrogen digestibility, BV, and net protein utilization were adversely affected. Protein digestibility corrected amino acid score was decreased for lysine, tryptophan, and sulfur containing amino acids.     

Characterization of hyacinth bean (Lablab purpureus (L.) sweet) seeds from Indonesia and their protein isolate

Hyacinth bean (Lablab purpureus (L.) sweet) seeds from Indonesia were characterized for the purposes of usage as a protein source. Protein isolate was prepared from the seeds using an isoelectric method, which was also used to characterize the physicochemical and functional properties. Hyacinth bean seeds have a moderate concentration of protein (17.1 ± 1.5%), and low concentration of HCN (1.1 ± 0.1 mg/100 g). However, before using the seeds as food, some treatments are needed to reduce their anti-nutritional factors, since the contents of trypsin inhibitor and phytate are 0.15 ± 0.02 TIU/mg and 18.9 ± 0.2 mg/g, respectively. Using the isoelectric preparation, the yield of protein isolate was low (7.38 ± 0.2 g per 100 g of the seeds), but the protein isolate had good colour, neutral odour, high protein content (89.8 ± 0.82%), and low ash (2.97 ± 0.36%). The protein isolate also had good functional properties, such as solubility, foaming capacity, and emulsifying activity. However, the foaming and emulsifying stabilities were low.     

运动食品——蛋白棒的研制

利用醇提大豆浓缩蛋白和玉米蛋白粉的复配改善氨基酸平衡,通过对蛋白原料的改性和选择开发运动食品——蛋白棒。结果表明采用乳化性大豆蛋白和乳化性玉米蛋白为蛋白原料,添加10%的蔗糖和调整含水量为20%,利用挤压膨化可得到较为理想的蛋白棒。     

桑叶叶蛋白提取工艺的研究

对桑树叶蛋白提取条件的优化进行了研究。结果表明，桑树叶蛋白提取的优化工艺条件为：室温下，以水为浸提荆，打浆时间3min，浸提时间4min，料液比1：5（叶片重比浸提剂体积，即g：m1），漫挺剂pH值8．0，絮凝温度75℃，调节提取液pH为5．0、8．0和13．0得到沉淀物，在60℃干燥。该工艺提取桑树鲜叶叶蛋白得率为：5．17％。     

大豆蛋白长绒棉涤纶混纺纱的生产

为了探讨大豆蛋白纤维、长绒棉及细特涤纶纤维细号混纺针织纱生产工艺,介绍了纤维的性能特点、纺纱工艺流程;针对大豆蛋白纤维纺纱静电现象严重的问题,生产中各工序通过优化配置工艺参数,采取严格控制相对湿度等技术措施,保证了纺纱顺利进行及成纱质量的稳定.     

牛奶蛋白纤维纯纺纱试验

为了探讨牛奶蛋白纤维纺纱工艺，根据牛奶蛋白纤维的性能特点和纺纱实践，分析了影响牛奶蛋白纤维成纱的主要因素。确定了合理的工艺参数，梳棉采用增大锡林针齿工作角，增大锡林与盖板隔距，并条采用“重加压，大隔距”工艺原则，粗纱选择较大捻系数，细纱采用不处理胶辊。从而提高成纱质量。     

Antioxidant activities of enzymatic‐hydrolysed proteins of dromedary (Camelus dromedarius) colostrum

This work investigated the antioxidant activities of dromedary colostrum proteins before and after hydrolysis by pepsin, trypsin, α‐chymotrypsin, pancreatin and papain. The enzymatic hydrolysis affected the degrees of hydrolysis, electrophoretic profiles, molecular weight distribution and hydrophobic/hydrophilic properties of the generated peptides. The antioxidant activities were evaluated using four antioxidant assays, including 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) radical‐scavenging activities, ferric reducing power and ferrous ion chelating activity. Interestingly, the antioxidant activities of dromedary colostrum proteins were enhanced after enzymatic hydrolysis. The highest antioxidant potential was obtained by pancreatic hydrolysates (P ≤ 0.05). These results suggest that dromedary colostrum protein hydrolysates are an important source of natural antioxidant peptides.