Thermal, morphological, and physicochemical characteristics of succinylated–crosslinked rice starches

Abstract

Background and objective Starches were isolated from two indigenous rice varieties of Pakistan, namely Basmati and Irri. Effect of succinylation followed by crosslinking was studied on thermal, physicochemical, and morphological characteristics of Basmati and Irri starches. Findings The percent succinylation and crosslinking were found to be (8.5, 5.9)% and (88.77, 47.49)%, respectively. SEM micrographs revealed surface erosion of starch granules after succinylation. However, modifications were not found to affect granular integrity of starches. The pasting temperature reduced but peak viscosity increased after succinylation. The reduction in peak viscosity of succinylated–crosslinked Irri and Basmati starches was 89% and 47%, respectively, when compared to their succinylated counterparts, which could be attributed to formation of diphosphate linkages after crosslinking. The DSC analysis suggested improvement in granular stability after dual modification. After 7 days of cold storage, native starch gels were found to have significantly higher hardness in comparison with single‐ and dual‐modified starches. Conclusions Significant physicochemical alterations occurred after aforementioned dual modification. Findings suggest the use of succinylated–crosslinked rice starches in frozen foods, weaning baby foods, and soft confectionary products. Significance and novelty Succinylation followed by crosslinking is a unique modification, which has never been reported on Pakistani Basmati and Irri rice starches. These findings provided fundamentals for the commercial applications of succinylated–crosslinked rice starches. Moreover, the use of inexpensive broken rice grains for preparation of dual‐modified starches could make product development cost‐effective.