Prebiotics characterization from traditional legumes and fruits sources and their synergistic effects on probiotic growth and short-chain fatty acid (SCFA) production

Abstract

Background

Prebiotics are nondigestible compounds that support gut health by promoting beneficial microbes. Mung beans, horse gram, figs (Ficus carica), and umbar (Ficus racemosa) are fiber-rich traditional foods with unexplored prebiotic potential. Studying them may aid in developing affordable functional foods.

Aim

To evaluate the prebiotic potential of four culturally significant plant-based foods—mung beans, horse gram, figs, and umbar.

Methodology

Total dietary fiber was quantified using the AOAC 991.43 enzymatic–gravimetric method. Oligosaccharides were extracted with 80% ethanol and characterized by Fourier-transform infrared spectroscopy. Insoluble dietary fiber (IDF) was used for batch culture growth experiments, whereas the extracted oligosaccharides were evaluated separately for gastric stability, fermentation, and short-chain fatty acid production. Gastric stability was assessed under simulated gastric conditions (pH 1–5, 6 h). Lactobacillus acidophilus survival under acidic stress (pH 2.0, 48 h), bacterial growth with oligosaccharide supplementation, and anaerobic fermentation (basal mineral medium, 48 h) were evaluated. Short-chain fatty acids were analyzed using high-performance liquid chromatography.

Results

Figs contained the highest total dietary fiber (26.98 g/100 g) and oligosaccharide content (47.5 g/100 g), followed by umbar, horse gram, and mung beans. Fourier-transform infrared spectroscopy confirmed inulin-type fructans. Oligomers showed partial gastric hydrolysis, with maximal degradation at pH 1.0 (66.1% mung bean, 36.7% horse gram, 44.1% fig, 58% umbar). L. acidophilus survived acidic stress and efficiently utilized plant-derived substrates, achieving 3.54 × 10⁷ cells/mL (horse gram, 48 h). Fermentation sustained 2.3–2.6 × 10⁷ cells/mL with moderate pH drops. Short-chain fatty acid analysis revealed lactic, propionic, and butyric acids (fig); acetic, formic, and 4-methylvaleric acids (horse gram, umbar); and lactic and propionic acids (mung bean).

Conclusion

These legumes and fruits demonstrate promising prebiotic potential. Although fig contained the highest levels of dietary fiber and oligosaccharides, horse gram IDF supported the greatest proliferation of L. acidophilus, indicating that both substrate composition and microbial utilization efficiency contribute to prebiotic effectiveness. These findings support the use of these foods in functional and synbiotic products to enhance gut health.