Variety Difference in Molecular Structure, Physico-chemical and Thermal Properties of Starches from Pigmented Rice

Abstract Starches isolated from three different pigmented rice varieties (Chak-hao Amubi, Chak-hao Poireiton, and Chak-hao Angangba) and investigated for their molecular structure and physico-chemical properties including amylose content, morphology, crystallinity, pasting viscosity, color, thermal property, swelling power and solubility. Significant differences were detected in physico-chemical and functional properties ( p ≤0.05 ) of rice starches. The amylose content results revealed that Chak-hao Angangba (1.93 %) and Chak-hao Poireiton (1.98 %) are waxy rice, and Chak-hao Amubi (3.16 %) is a very low-amylose rice. The morphology of rice starch granules shown polyhedral edges with an irregular shape; and the XRD patterns of rice starches exhibited A-type crystalline patterns with peaks at 2θ=15.1°, 17.1°, 18.2° and 23.0°. Waxy rice starches shown higher peak viscosity and enthalpy with lower gelatinization temperatures than very low amylose rice starches. The pasting viscosity, swelling power and solubility crystallinity of rice starches were varied significantly ( p ≤0.05 ). Finally, the present study provides knowledge for the utilization of starches isolated from three pigmented rice varieties grown in North-Eastern part of India that would be relevant for both domestic and industrial applications.