Effects of alkaline fermentation time on anti-nutrients, structural interactions and bioactive profile of locust bean (Parkia biglobosa)

Abstract

Present investigation aimed at evaluating the impart of different fermentation times (0, 24, 48 and 72 h) on compositional parameters, antinutritional factors, structural & molecular attributes and functional properties of locust bean seeds. Fermentation time linearly reduced (p<0.05) the antinutritional compounds as phytic acid (12.59 to 5.16 mg/g), saponin content (6.87 to 1.92 mg/g) and tannin content (2.86 to 1.03 mg tannic acid/g) predominantly due to high hydrolytic activity as revealed by scanned electron micrographs. Fourier transform infrared spectroscopy and X-ray diffraction studies further revealed some significant changes in structural and molecular interactions which could be attributed to gelatinization of starch during hydrothermal treatment prior to fermentation in addition to fermentation during bioprocessing. Amylolytic and proteolytic activities enhances the in-vitro starch (5.29 to 24.82 g/100g) and protein digestibility (66.47 to 75.29 g/100g). Significant changes (p<0.05) were also noted in functional components including water and oil absorption capacity, water solubility and emulsification properties. Further, weakening of gel was also observed as a consequence of fermentation ascribing to lower water retention power due to enzymatic breakdown of starch molecules. Data were statistically exposed to Pearson’s correlation and Principal component analyses which strengthened the outcome to validate the differences among the variables and observations.