The importance of amylopectin molecular size in determining the viscoelasticity of rice starch gels. (15th May 2019)

• Record Type: Journal Article
• Authors: Li, Hongyan; Lei, Ningyu; Yan, Shu; Yang, Jingyuan; Yu, Ting; Wen, Yangyang; Wang, Jing; Sun, Baoguo
• Is Part Of: Carbohydrate polymers. Volume 212(2019)
• Page Start: 112
• Page End: 118
• Publication Date: 2019-05-15
• Subjects: Amylose content -- Rice -- Amylopectin -- Molecular size -- CLDs -- Viscoelasticity; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2019.02.043
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Starches with similar amylose content show different gel strengths. Starch samples display different molecular sizes. Starch CLDs are parameterized by model fitting, but show no large variations. Amylopectin molecular size significantly contributes to gel viscoelasticity. A postulated molecular mechanism is put forward to explain the observations. Abstract: Amylose content as the key indicator in determining the viscoelasticity of starch gels has been widely accepted. In this study, 7 rice varieties are deliberately selected to investigate the structural basis of gel viscoelasticity of starches with similar amylose content. By quantifying starch molecular structure and rheological properties of starch gels, we find (i) starch with similar amylose content forms significantly different gel networks in terms of K *, n * and tan δ ; (ii) molecular sizes of rice starches are significantly different between samples; (iii) the chain-length distributions (CLDs) of both amylopectin and amylose are parameterized by mathematic model fitting, and no large variations of these fitted parameters between samples are observed; (iv) amylopectin size are negatively correlated with K * ( p < 0.01) while positively correlated with tan δ ( p < 0.05). Molecular mechanisms are put forward to explain the role of amylopectin size in contributing to the strength of gel network.