Department of Food, Environmental, and Nutrition Sciences, University of Milan, Italy.
Carbohydr Polym. 2013 Feb 15;92(2):1865-72. doi: 10.1016/j.carbpol.2012.11.047. Epub 2012 Nov 26.
Structural changes of starch and proteins in rice pasta were investigated as a function of raw-materials and pasta-making conditions, and their impact on cooking behaviour and glycaemic index was assessed. Rice pasta was prepared from untreated or parboiled rice flour by conventional extrusion or by extrusion-cooking. Starch structure was studied by assessing starch accessibility to specific enzymes (α-amylase and pullulanase), and by evaluating the molecular properties of fragments from enzymatic action. Protein solubility in presence/absence of chaotropes and accessibility of protein cysteine thiols allowed to evaluate the intensity and nature of inter-protein interactions. Parboiling stiffens the protein network in rice flour and makes starch more accessible to hydrolysis. Pasta-making induced further changes in the starch structure, that were most evident in pasta made from untreated rice and were mainly related to the amylopectin fraction. Thus, the interplay among structural modifications on starch and/or proteins affects the features of products.
研究了大米面食中原材料和面食制作条件对淀粉和蛋白质结构的影响，并评估了它们对面食烹饪行为和血糖指数的影响。通过常规挤压或挤压蒸煮，从未经处理或半熟化的米粉制备大米面食。通过评估淀粉对特定酶（α-淀粉酶和普鲁兰酶）的可及性，并评估酶解产物的分子特性，研究了淀粉结构。在存在/不存在变性剂的情况下评估蛋白质的溶解度和蛋白质半胱氨酸巯基的可及性，可评估蛋白质间相互作用的强度和性质。半熟化使米粉中的蛋白质网络变硬，并使淀粉更容易水解。面食制作进一步改变了淀粉的结构，在未处理的大米面食中最为明显，主要与支链淀粉有关。因此，淀粉和/或蛋白质结构修饰之间的相互作用会影响产品的特性。
