Abstract
Probiotics like Lactobacillus sp. are extensively studied for their beneficial host interactions, including the gut-brain axis, anti-inflammatory effects, immune system interactions, restoration of gut dysbiosis, and anti-aging effects. In the current study, pearl millet was fermented with Lactobacillus plantarum strains DHCU 70 and MCC 5231, which enhanced the nutritional, bioactive, and functional properties of derived probiotic beverages. Compared to unfermented controls, fermented beverages exhibited increased protein content and vitamins B(1), B(2,) and B(3), with decreased carbohydrate and dietary fiber levels. The probiotics have maintained viability exceeding 12 log CFU/mL and showed resistance to harsh gastrointestinal conditions. Fermentation increased total phenolic content from 13.38 ± 0.40 mg GAE/100 g to 42.10 ± 2.65 mg GAE/100 g (LPDB) and 47.76 ± 1.37 mg GAE/100 g (LPMB) and total flavonoid content from 13.01 ± 1.18 mg QE/100 g to 23.12 ± 2.73 mg QE/100 g and 24.21 ± 0.98 mg QE/100 g, respectively. Antioxidant assays showed DPPH radical scavenging improved by 37%, ferrous ion chelation rose from 71.69 ± 0.09 mg TE/100 g to 91.45 ± 0.006 mg TE/100 g, ABTS scavenging increased from 71.62 mg TE/100 g to 82.51 ± 0.04 mg TE/100 g (LPDB) and 89.74 ± 0.04 mg TE/100 g (LPMB) and superoxide radical inhibition rose from 51.40 ± 0.98% to 81.77 ± 0.03% (LPDB) and 79.92 ± 0.02% (LPMB). In the in vivo model, Caenorhabditis elegans, fermented beverage treatments significantly improved health-span parameters like head-swing frequency (13.51% increase), body bend frequency (8.41% increase), pharyngeal pumping (8.15% increase) with reduced lipofuscin accumulation and intracellular reactive oxygen species while median lifespan extended beyond 24 days versus 14-16 days in controls (p < 0.05). Gompertz mortality modeling revealed a significant decrease in the aging rate parameter, indicating systemic mitigation of stress-induced physiological decline. These combined nutritional, bioactive, and in vivo longevity results underscore the potential of L. plantarum-fermented pearl millet beverages as functional nutraceuticals that target oxidative stress and promote healthy aging.