Bioactive compounds and digestible starch variability of rice, maize, green gram, and soy grains with different levels of germination

Abstract

Germination is a sustainable and economical process that can enhance the bioactivities of commonly consumed cereal and pulses, contributing to healthier diets. Its effectiveness in increasing bioactives depends on the germination conditions. This study examined the impact of varying germination periods (2, 4, 6, and 8 days) following 12 h of steeping on rice, maize, green gram, and soy, focusing on key bioactive compounds, including total polyphenols, flavonoids, and total digestible starch. Cereal and pulses germinated for eight days demonstrated a significantly higher (P < 0.05) total polyphenol and flavonoid content along with elevated antioxidant activity. Antioxidant activity strongly correlated to increased total polyphenol and flavonoid levels throughout the extended germination period. Moreover, the total digestible starch content (TDS) in rice, maize, and soy increased significantly (P < 0.05) because of the hydrolysis of starch molecules, while green gram showed twofold decrease in TDS, indicating the impact of germination on TDS content may differ across the type of cereal and pules. Using locally grown Sri Lankan grain varieties, such as rice, maize,green gram,and soy, this study fills the gap in existing database on the investigation of bioactive compounds and total digestible starch content, exploring the potential of germination of cereal and pulses to use in nutritionally rich products in the food and agriculture industry with a focus on sustainable food systems and healthier eating habits.