Optimized Fermentation Conditions of Pulses Increase Scavenging Capacity and Markers of Anti-Diabetic Properties

Fermented pulses offer health benefits due to their antioxidant and antidiabetic properties. The objective was to optimize the fermentation conditions of black bean (BB), black eyed pea (BEP), green split pea (GSP), red lentil (RL), and pinto bean (PB), using Lactiplantibacillus plantarum 299v (Lp299v), based on the antioxidant-scavenging capacity and the ability to modulate type-2 diabetes markers. Pulses were grounded, dispersed in water, hydrolyzed with α-amylase, and pasteurized and inoculated with Lp299v. Optimization was performed by using the Box-Behnken response surface methodology, with the fermentation time, bacterial concentration, and flour concentration as variables. The values of antioxidant capacity measured as 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging of RL, BEP, PB, BB, and GSP were 57%, 68%, 71%, 72%, and 83%, respectively, under optimal conditions (8-9 h, 0.76-3.5 × 10⁹ a colony-forming unit (CFU)/mL, and 5.5-15 g flour/100 mL). These models demonstrated strong predictive power (p < 0.01) and a non-significant lack of fit (p ≥ 0.05). Additionally, fermentation increased the soluble protein content (3-10 mg/mL) and significantly inhibited dipeptidyl peptidase-IV and α-glucosidase activities by 40-70% and 30-60%, respectively. These results suggest that fermentation with Lp299v enhances the nutritional and functional quality of pulses, producing bioactive ingredients with antioxidant and antidiabetic potential. These functional ingredients may be used in the development of dietary interventions or as part of health-promoting foods, especially those targeted at the management of type-2 diabetes.