Structural changes of chemically modified rice starch by one-step reactive extrusion. (1st August 2019)

• Record Type: Journal Article
• Authors: Cai, Canxin; Wei, Benxi; Tian, Yaoqi; Ma, Rongrong; Chen, Long; Qiu, Lizhong; Jin, Zhengyu
• Is Part Of: Food chemistry. Volume 288(2019)
• Page Start: 354
• Page End: 360
• Publication Date: 2019-08-01
• Subjects: Reactive extrusion -- Chemical modification -- Degradation -- Microstructure -- Starch-lipid complex; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2019.03.017
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: New crystalline complexes were formed after REX process. Esterification showed greater impacts on starch in dual modification by REX. Esterification retarded the heterogeneous degradation of starch molecules. Cross-linking enhanced the heterogeneous degradation of starch molecules. Abstract: Structural changes of chemically modified rice starch (CMRS) by one-step reactive extrusion (REX) via esterification, acetylation, hydroxypropylation, and cross-linking or dual-modification (hydroxypropylation-cross-linking and acetylation-cross-linking) were investigated. REX treatments exhibited a significant effect on the structure of rice starch granules, resulting in the destruction of the starch crystalline structure and formation of new crystalline complexes. The original A-type crystalline structure was transformed to VH -type after REX treatments, which were further confirmed by DSC experiments since a new endotherm at 100–122 °C was detected. Due to the susceptibility differences in shear-induced breakdown of amylopectin and amylose, the molecular degradation was heterogeneous and retarded by esterification but enhanced by cross-linking. Morphology analysis showed that the original starch granular structure was lost and replaced with a rougher and more irregular structure. In consequence, REX process exerted significant influences on rice starch granules which enhanced its resistance to enzyme hydrolysis.