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.     

小米粥油的制作工艺优化

本研究以小米为原料,研究米粥油的制作工艺.以感官评分、可溶性固形物含量和碘蓝值为考察指标,通过单因素试验研究浸泡时间、浸泡温度和蒸煮时间对米粥油品质的影响,确定各因素的最佳水平.在此基础上,进一步采用Box-Behnken试验设计构建多项式回归方程模型,并通过响应面试验分析,确定了米粥油的最佳工艺参数为:浸泡时间41 ...     

不同冻结方式对非发酵面团的水分状态及品质特性的影响

本实验从冻结方式的应用场合出发,对比研究了家庭常用的低温冰箱冻结（cryogenic refrigerator freezing,RF）、传统企业化生产采用的螺旋隧道冻结（spiral tunnel freezing,SF）、新兴待开发的液氮喷淋冻结（liquid nitrogen spray freezing,LF）处理对非发酵面团的水分状态、质构特性、流变学特性以及微观结构产生的影响。结果表明,3?种冻结方式的冻结速率存在明显差异,其中LF（1.33?℃/min）＞SF（0.31?℃/min）＞RF（0.08?℃/min）,且随着冻结速率减慢,面团的冻结失水率呈上升趋势,强结合水T21与弱结合水T22的峰面积比例呈下降趋势,面团的质构品质和流变学特性变差,尤其是硬度变大。由面团的微观结构分析发现,冷冻速度越慢,造成面团中的孔隙较大,面团的组织结构致密程度较差。综上,经LF处理后解冻的面团与新鲜面团的品质最相近,其次是SF和RF处理,表明新兴的LF处理比传统企业化的SF处理更有优势,而家庭常用的RF处理不利于保持面制食品的品质。     

热处理和高速剪切对豌豆蛋白水解效率及其水解物性质的影响

为提高豌豆蛋白的酶水解敏感性及其水解物的抗氧化活性,分别考察95℃、10 min的热处理和10 000×g、10 min的高速剪切对豌豆蛋白水解性能的影响并探究其改善原因。结果表明,热处理和高速剪切均提高了豌豆蛋白的水解度、氮回收率以及水解物的抗氧化活性(p<0.05),高速剪切提高了不溶性聚集体比例,而热处理使其降低,其中热处理优化效果更为明显,水解度和氮回收率分别增加了21.1%和9.6%,不溶性聚集体降低了27.7%。热处理和高速剪切使豌豆蛋白溶解度显著提高,使豌豆蛋白水解物氨基酸含量和小分子肽比例显著增加(p<0.05)。采用红外光谱和扫描电子显微镜观察预处理前后豌豆蛋白的二级结构和表观形貌的变化发现,两种预处理方式在不同程度上促使了豌豆蛋白紧密结构的展开,有助于实现豌豆蛋白的高效水解。综上,热处理相对于高速剪切更有利于提高豌豆蛋白的水解效率。