Traditional-aromatic white and black rice responded differently on physical, biochemical and molecular structure in relation to storage duration

Determining the changes in rice-culinary quality and starch multi-layer structure during a period of 0–1–2 years of storage was the ultimate objective of this study. The main purpose of this work was to determine how long-term storage affected the physico-chemical properties of rice starch that was extracted from Kanakchur, Kala-Bhat, the native rice genotypes and MTU-1153, the widely cultivated high-yielding check (control) genotype of West Bengal, in order to identify changes in rice culinary quality-related attributes. To investigate the quality of stored grain, we conducted a series of experiments on grain physicochemical characteristics, culinary qualities, and molecular structure using FTIR spectroscopy and X-ray diffraction analysis. The findings of the physicochemical properties revealed that the moisture content decreased from 12 to 9% in Kala-Bhat, the swelling index shifted from 15.5 to 17.8 g/g in Kanakchur, the solubility percentage elevated from 0.7 to 1.9% in Kala-Bhat. Beside this, the total phenol content reduced from 554 to 150 mg gallic acid equivalent (GAE)/100 g and DPPH (2,2 diphenyl-1-picrylhydrazyl) inhibitory concentration (IC50) value increases from 12 to 55 mg fresh weight (FW)/ml after 2 years of storage. The amylose percentage and crude total protein content showed no significant changes over time. After 2 years of storage, there was an alarming increase (p < 0.05) in the ratio of FTIR peaks at 1047 cm⁻1 and 1022 cm⁻1. From the present study, it is recommended that storage of rice is possible up to 2 years in suitable granary conditions with ensured maximum quality.