In vitro and In vivo studies on intragastric soya protein–polysaccharide gels in a beverage matrix

Intragastric gelation is a mechanism whereby a consumed liquid food gels under the acidic gastric condition. It was hypothesised that intragastric gelation would result in satiety due to delayed gastric emptying. Three treatment beverages that is soya protein isolate (SPI) with λ‐carrageenan (SPI‐LC; high viscosity, gelling), guar gum (SPI‐GG; high viscosity) and no polysaccharide (SPI; low viscosity) were given to twenty participants in a randomised 3 × 3 double‐blind within‐subject crossover design trial and asked to rate their hunger and fullness scores (visual analogue scale; VAS) before and up to 60 min after consumption of the beverage. Results show that there were no significant effects on hunger, fullness and energy intake after consuming the SPI‐LC (gelling) beverage compared to the SPI‐GG beverage, but did evoke weak satiety signals up to 20 min after consumption when compared to the control (low‐viscosity) SPI beverage. Therefore, intragastric gelation does not result in satiety in this study.     

脱脂豆粕中大豆分离蛋白提取工艺的研究

介绍了大豆分离蛋白的生产工艺,以脱脂豆粕为原料,经过碱提、分离残渣、酸沉、分离蛋白、再干燥得到产品。其中,对从脱脂豆粕中碱提过程进行了重点研究,通过单因素和正交试验,确定了碱提的最佳条件:NaOH溶液质量浓度为1.0g/L,温度为50℃,时间为40min。     

大豆蛋白质塑料特性的研究

考察了不同的湿度环境对大豆蛋白质塑料力学性能的影响，随着环境湿度提高，拉伸强度下降，断裂伸长率提高，差示扫描量热（DSC）曲线的峰升高；拉伸强度随着测试温度的提高而下降并且在高温时如140℃也能检测到拉伸强度；储能模量随温度升高而下降，随甘油含量的增加，力学损耗峰出现在更低的温度，随时间延长，模量逐渐升高，温度越高，模量升高越快。     

大豆分离蛋白-麦芽糊精聚合物的结构特征

以大豆分离蛋白(SPI)和麦芽糊精(MD)为原料制备不同接枝度的SPI-MD聚合物,通过巯基含量测定、SDS-PAGE凝胶电泳、差式量热扫描、傅里叶红外光谱、电子扫描显微镜和圆二色谱分析SPI和不同接枝度(10%、20%、30%、40%)SPI-MD聚合物结构特征的变化。结果表明：随着接枝度的提高,SPI-MD聚合物的巯基含量逐渐降低、变性温度先提高后降低、α-螺旋和β-转角的结构含量减少以及β-折叠和无规则卷曲结构含量增多;并且证明了SPI和MD是以共价键的结合方式聚合及SPI中7S与MD反应活性较高;SPI-MD聚合物的微观结构松散,呈多孔状。     

Heat Curing of Soy Protein Films at Selected Temperatures and Pressures

Vacuum and temperature effects on moisture content, water vapor permeability (WVP), color (L, a, b, and ΔE), tensile strength (TS), elongation (E), and total soluble matter (TSM) of soy protein isolate (SPI) films were examined. SPI films were cured at 60, 72.5, or 85 °C and at 101.3, 81.32, or 61.32 kPa for 24 h. As a result of heat-curing moisture content, WVP, E, and TSM decreased, and total color difference and TS increased. Pressure, individually and interactively with temperature, significantly affected film moisture content, TS, and TSM.     

Solubility,functional properties,ACE‐I inhibitory and DPPH scavenging activities of Alcalase hydrolysed soy protein hydrolysates

Soy proteins are less soluble at acidic pH value, which impedes their utilisation in acidic beverages. Soy protein isolate (SPI) was hydrolysed using varying Alcalase concentrations (0.0001–2.0 U g^?1 protein) at different pHs (3.0–4.0). Degree of hydrolysis (DH) of soy protein hydrolysates (SPH) at pH 3.0, 3.5 and 4.0 were 5.0–10.7%, 2.3–6.1% and 0–5.4%, respectively, while solubilities ranged from 70.7 to 74.9%, 18.8 to 51.2% and 7.1 to 40.4%, respectively. The highest solubility (74.9%) was observed at pH 3.0 with 1.5 U Alcalase per g protein (DH = 9.2%). Emulsifying activities of SPHs at pH 3.0 and 4.0 ranged from 0.49 to 0.63 AU and 0.19 to 0.24 AU, respectively, while the emulsifying stabilities were 12.2–14.7 min and 18.7–56.0 min, respectively. The foaming capacity at pH 3.0 and 4.0 was 44.9–46.3 mL and 31.2–41.3 mL, respectively, whereas the foaming stability was 25.5–35.2 min and 12.8–15.1 min, respectively. However, hydrolysates had an insignificant effect on ACE‐I inhibitory and DPPH scavenging activities in comparison with SPI.