BIOACTIVE AND TECHNO-FUNCTIONAL PROPERTIES OF PROTEINS FROM GERMINATED RICE AND BEANS: UNLOCKING NEW INGREDIENTS FOR PLANT-BASED FOODS APPLICATION

The plant protein market has been rapidly expanding as consumers increasingly seek alternatives to traditional animal-derived proteins, driven by concerns over animal welfare, environmental sustainability, and greater awareness of health and ethical issues. However, despite this growing demand, the application of plant proteins in plant-based formulations still faces important technological limitations, such as low solubility. These challenges highlight the importance of thoroughly evaluating the properties of plant proteins to optimize their performance in food applications and meet consumer expectations. The aim of this study was to characterize the bioactive and techno-functional properties of proteins extracted from germinated brown rice (Oryza sativa) and carioca beans (Phaseolus vulgaris), as well as from their blends. The optimal germination time was determined in a previous study and defined as 72 hours for rice and 48 hours for beans. Proteins were extracted from flours obtained from germinated seeds by alkaline solubilization (pH 12 for rice and 9.0 for beans) followed by isoelectric precipitation at pH 4.5, and subsequently freeze-dried for 48 hours. Protein blends were prepared in different proportions: in ratios of 1:1 (“A:F 1:1”), 2:1 (“A:F 2:1”), and 1:2 (“A:F 1:2”). Rice proteins exhibited higher antioxidant capacity (756, 287, and 458 µmol of Trolox Equivalents per 100 g for ABTS, DPPH, and FRAP, respectively), whereas bean protein was distinguished by its higher total phenolic content (123 mg of Gallic Acid Equivalents per 100 g). Regarding antidiabetic activity, the sample A:F 1:2 blend showed the highest α-amylase inhibition capacity (47%), while A:F 2:1 blend demonstrated the greatest α-glucosidase inhibition (19%). Techno-functional analyses revealed that germinated bean protein exhibited superior properties in solubility (62.54% at pH 7), emulsifying capacity (96.64%), foaming capacity (64.58%), and gelling ability (minimum gelling concentration at 0.12 mg mL⁻¹). In contrast, rice protein stood out for its high water-holding capacity (2.56 g g⁻¹ in the A:F 2:1 blend) and oil-holding capacity (1.20 g g⁻¹ in pure rice protein). The sample A:F 2:1 blend also showed the best foam stability (96% of foam retained after 60 minutes). These findings highlight the potential of the protein concentrates and their blends as promising ingredients for the development of foods with enhanced technological functionalities and nutraceutical appeal. The use of accessible raw materials that are culturally familiar to the Brazilian population may further support their acceptance and incorporation into plant-based formulations.