Morphological, Thermal, and Rheological Properties of Starch from Brown Rice and Germinated Brown Rice from Different Cultivars

Morphological, thermal, functional, pasting, and rheological properties of starch from BR (Brown rice) and GBR (Germinated brown rice) (PB1, PS44, PB1509, PB1121, PS5) are investigated. Scanning electron microscopy shows the presence of rougher and slightly eroded pits starch granules after germination. Starch from both the BR and GBR has the highest proportion of granules of 5-10 mu m size and the lowest of 20-60 mu m size. Starch from GBR shows lower gelatinization temperatures and enthalpy of gelatinization. GBR starch has a higher amount of long side chains and lower short side chains of amylopectin as compared to BR starch. Starches from BR show higher moduli as compared to their counterpart starches from GBR. GBR starch from different rice cultivars shows different amylopectin molecular structures, crystallinity, and thermal properties than BR starch. The lower paste viscosities and transition temperatures of GBR starch make it more suitable for the formulation of food products where a higher amount of starch is required without a rise in viscosity.

Automated summary

This study investigated the morphological, thermal, functional, pasting, and rheological properties of starch from brown rice and germinated brown rice. The starch from germinated brown rice exhibited rougher starch granules and lower gelatinization temperatures and enthalpy. It also had higher long side chain content and lower short side chain content compared to starch from brown rice. Additionally, germinated brown rice starch showed lower moduli and transition temperatures, making it more suitable for food formulations with higher starch content but without an increase in viscosity.