State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
Carbohydr Polym. 2019 Jun 1;213:192-198. doi: 10.1016/j.carbpol.2019.02.089. Epub 2019 Feb 27.
Modifications of molecular structure, and of short- and long-term retrogradation properties, in rice starch by an "improved extrusion cooking technology" (IECT) were studied. IECT decreased starch molecular size in the order high speed / high temperature > low speed / high temperature > high speed / low temperature > low speed / low temperature. Degradation was mostly of amylopectin and insignificant for amylose. The reduction of water mobility and the increase of storage modulus were both less than normal in extrusion: IECT inhibited short-term retrogradation. Crystallinity and retrogradation enthalpy were increased after long storage: IECT accelerated the long-term retrogradation of starch. The greater the starch degradation by IECT, the more short-term retrogradation was inhibited and long-term retrogradation accelerated. These results show that, under appropriate conditions, IECT is a type of extrusion which can be used to change retrogradation properties of rice starch that have not been previously available.
采用“改良挤压蒸煮技术”（IECT）对大米淀粉的分子结构及其短期和长期回生特性进行了改性研究。IECT 按高速/高温＞低速/高温＞高速/低温＞低速/低温的顺序降低淀粉的分子大小。降解主要发生在支链淀粉上，直链淀粉的降解不明显。挤压过程中，水流动性的降低和储能模量的增加均低于正常水平：IECT 抑制短期回生。长期储存后结晶度和回生焓增加：IECT 加速淀粉的长期回生。IECT 对淀粉的降解越大，短期回生抑制越明显，长期回生加速越明显。这些结果表明，在适当的条件下，IECT 是一种挤压方式，可用于改变以前无法获得的大米淀粉的回生特性。
