Germination time: impact on nutritional, thermal, and paste properties of red rice

The study investigates how varying germination times affect the nutritional, thermal, and pasting properties of red rice. Germination was conducted over 32 h, with aliquots collected every 2 h starting from 18 h for property evaluation.

At all evaluated germination times, the red rice samples exhibited low to intermediate amylose levels, while resistant starch content remained relatively constant (approximately 15-20%). Structural changes in the starch were observed: the peak viscosity decreased, maximum gelatinization of the granules occurred at 76 °C, and spectroscopic bands characteristic of this polysaccharide were detected at 3400 cm^-1 (OH stretching) and within the 1150-1000 cm^-1 range (COH and COC stretching). Protein and fiber content remained unchanged throughout the process, whereas carbohydrate content varied by 10 g kg^-1. Protein digestibility increased after 26 h and continued to rise until the end of germination, while starch digestibility decreased throughout the process, particularly between 24 and 26 h.

The thermal properties of the grains remained unchanged, as did the starch digestibility, suggesting the potential application of this flour in gluten-free bakery products. © 2025 Society of Chemical Industry.