Faculty of Agriculture, Niigata University , 8050 Ikarashi-ninocho, Nishi-ku, Niigata 950-2181 Japan.
J Agric Food Chem. 2011 Oct 12;59(19):10665-76. doi: 10.1021/jf200973x. Epub 2011 Sep 15.
As ae mutant rice, such as EM10, lacks the starch branching enzyme IIb, its amylopectin contains more long-chain glucans than that of ordinary Indica and Japonica rice grains. Although boiled grains of ae rice cultivars are too hard and nonsticky for table rice, they are promising in terms of biofunctionality, such as prevention of diabetes. The present paper investigates the characterization of a novel group of four ae mutant rice cultivars (EM72, EM145, EM174, and EM189). They were subjected to the evaluation for their main chemical components, physical properties, and enzyme activities at different grain conditions (raw milled rice, roasted rice, boiled rice, and rice boiled after preroasting). These mutant rice grains are characterized by high apparent amylose, high protein and high glucose contents, high pasting temperature, high α-amylase activities, high resistant starch, and low degree of gelatinization. A novel method was developed to maintain the high resistant starch contents of gelatinized rice grains. Rice boild after preroasting showed a higher ratio of resistant starch and a lower amount of glucose than ordinary boiled rice. It became possible to produce high-quality and biofunctional pregelatinized rice flours by boiling with frozen fruits, such as tomatoes, after rice grains had been preroasted. These ae mutants were found to be suitable materials for rice/fruit or rice/vegetable products to serve as palatable, low-glucose, and high resistant starch rice products.
作为一个 ae 突变体水稻，如 EM10，缺乏淀粉分支酶 IIb，其直链淀粉含有比普通籼稻和粳稻粒更多的长链葡聚糖。虽然 ae 水稻品种的煮米太硬，不适合做米饭，但它们在生物功能方面很有前途，如预防糖尿病。本文研究了一组新型的 4 种 ae 突变体水稻品种（EM72、EM145、EM174 和 EM189）的特性。对它们的主要化学成分、物理性质和不同谷物条件下（原糙米、烤米、煮米和预煮后煮米）的酶活性进行了评价。这些突变体水稻粒的特点是直链淀粉含量高、蛋白质和葡萄糖含量高、糊化温度高、α-淀粉酶活性高、抗性淀粉含量高、凝胶化程度低。开发了一种新方法来保持已凝胶化的水稻粒中抗性淀粉的高含量。预煮后再煮的米饭比普通煮米饭具有更高的抗性淀粉比例和更低的葡萄糖含量。通过在预煮后的大米中加入冷冻水果（如西红柿）煮沸，可以生产出高质量的生物功能型预糊化大米粉。这些 ae 突变体被发现是适合生产大米/水果或大米/蔬菜产品的材料，可以作为口感好、低葡萄糖、高抗性淀粉的大米产品。
