GERMINATION AS A STRATEGY TO IMPROVE THE BIOACTIVE AND TECHNO-FUNCTIONAL PROPERTIES OF RICE AND BEAN

In recent years, germination has emerged as a promising strategy to improve the bioactive and techno-functional properties of plant ingredients. Rice and beans, widely consumed in Brazil, are nutritionally complementary – rich in methionine and lysine, respectively – and stand out as low-cost, accessible, and culturally familiar raw materials. Their germinated grains hold great potential for the development of plant-based foods with improved functionality and consumer appeal. The aim of this study was to characterize the bioactive and techno-functional properties of germinated brown rice (Oryza sativa) and carioca bean (Phaseolus vulgaris) flours. Germination was carried out in the absence of light at 25 °C for 72 hours, with samples collected every 24 hours to determine the optimal germination time. Non-germinated grains were used as controls. Whole flours obtained from germinated and non-germinated grains were analyzed for their antioxidant activity, total phenolic content, and techno-functional properties. In beans, germination maintained the antioxidant potential measured by the ABTS method (maximum value of 1542 µmol TE 100 g⁻¹ after 72 hours), but reduced the activity measured by DPPH and FRAP, with the highest values observed in the control sample (646 and 350 µmol TE 100 g⁻¹, respectively). For rice, germination increased the activity determined by the DPPH method (365 µmol TE 100 g⁻¹ at 24 hours), whereas ABTS and FRAP values were higher in the control sample (784 and 344 µmol TE 100 g⁻¹, respectively). Nevertheless, total phenolic content increased in both grains after germination, reaching maximum values of 133 and 485 mg GAE 100 g⁻¹ in rice and bean samples germinated for 72 hours, respectively. Regarding techno-functional properties, rice flour showed improved water-holding capacity – WHC (1.48 g g⁻¹ at 48 hours), as well as oil-holding capacity – OHC (0.96 g g⁻¹) and protein solubility (23.64%) at 72 hours. In beans, the highest WHC (1.80 g g⁻¹) and protein solubility (100%) were observed at 48 hours, while OHC peaked at 1.16 g g⁻¹ after 72 hours. Based on these results, the optimal germination times for obtaining rice and bean protein concentrates were established as 72 hours for rice and 48 hours for beans. Germination of rice and beans proved to be an effective strategy to improve the techno-functional properties of these grains, notably protein solubility. The process also increased the content of phenolic compounds, further contributing to the bioactive potential of these ingredients and highlighting their suitability for developing functional plant-based foods.