Development of a yogurt drink produced from pigeon pea (Cajanus Cajan (L.) Millsp.) that exhibits glucose-lowering effects in diabetic mice

This research explored the utilization of pigeon pea as a substrate for yogurt fermentation using lactic acid bacteria as starters and assessed the glucose-lowering effects of the products. Lactiplantibacillus plantarum G6 (LpG6), an indigenous lactic acid bacteria isolated from pigeon pea’s soaking water, was selected as the fermentation starter. Pigeon pea juice fermented with LpG6 (PPJ-G6) or yogurt cultures (PPJ-STLB) had increased phenolic and flavonoid contents, showed β-glucosidase activity, and released aglycones daidzein and genistein that increase antioxidant activity. The phenolic and flavonoid contents in PPJ-G6 were 77.59 ± 0.07 mg GAE/g dry weight (DW) and 75.10 ± 0.01 mg QE/g DW, whereas those in PPJ-STLB were 82.98 ± 0.05 mg GAE/g DW and 61.08 ± 0.03 mg QE/g DW, respectively. PPJ-G6 produced 0.16% ± 0.03% butyrate and 0.43% ± 0.01% propionate, whereas PPJ-STLB produced 0.17% ± 0.03% butyrate and 0.36% ± 0.02% propionate. PPJ-G6 released 1.047 and 0.235 µmol/g of daidzein and genistein, whereas PPJ-STLB released 2.869 and 0.313 µmol/g of the same, respectively. Pigeon pea yogurt administration reduced (p < 0.05) blood glucose levels in diabetic BALB/c mice. Diabetic mice treated with PPJ-G6 (T3) showed a 36.60% blood glucose reduction, whereas those treated with PPJ-STLB (T4) showed a 44.08% reduction, which was comparable to the 49.07% reduction noted in diabetic mice treated with metformin (T1). Untreated diabetic mice (T2) showed increased glucose levels, whereas nondiabetic mice (T5) showed no changes in blood glucose levels. Overall, blood sugar levels in T3 mice were significantly lower (p < 0.05) than those in T2 mice but higher than those in T1 mice. These findings suggest that pigeon pea yogurt could function as a nutritional glucose-lowering agent, potentially improving diabetes mellitus management in rural communities with limited access to medical treatments.