The present study investigated the effect of fermentation by Rhizopus oligosporus on the nutritional, functional, colour and microstructural properties of some commonly consumed legumes, that is, chickpea (kabuli and desi), pigeon pea and soybean. Results revealed a substantial (P < 0.05) increment in the protein (5-14%) and ash (5-15%) contents as well as those of essential (13-21%) and non-essential (3-15%) amino acids with fermentation. Fatty acid composition showed the varied concentrations of polyunsaturated, monounsaturated and saturated fatty acids in fermented legumes. Further, fermentation significantly (P < 0.05) modified the functional and colour properties of legumes. The alteration in the structural conformation of legumes upon fermentation was observed with scanning electron microscopy which confirmed the enzymatic action on the proteins, fibres and lipid bodies. The results concluded that fermentation of these legumes could be a potential approach in developing the novel functional foods to address the concerns of food and nutrition securities.

Research background. Legumes are superior sources of macro- and micronutrients which can be further enhanced by fermentation. This can assist in addressing the food security concerns. The present study aims to determine the effect of fermentation by Rhizopus oligosporus on nutritional and antinutritional composition of some commonly consumed legumes. Experimental approach. Chickpea (kabuli and desi), pigeon pea, and soybean were fermented with Rhizopus oligosporus (at 34 °C for 52 h), dried at 45 ºC for 16-18 h and milled. Unfermented and fermented flours were evaluated for antioxidant potential, phenolic composition, antinutrients, mineral composition and FTIR spectra. Results and conclusions. Fermentation significantly (p<0.05) enhanced the total phenolic and flavonoid contents, and antioxidant properties (radical scavenging activity, reducing power, ferric reducing antioxidant power and metal chelation) of chickpea kabuli and desi, and soybean. Although fermented pigeon pea exhibited excellent antioxidant properties, the effect of fermentation on such properties was either minimal or insignificant. Additionally, specific phenolics were quantified using HPLC which showed higher concentration of certain compounds such as chlorogenic acid, p-hydroxybenzoic acid, gallic acid and vanillic acid in fermented legumes. Phytic acid in all the fermented legumes reduced (p<0.05), however trypsin inhibition increased (p<0.05). In chickpea kabuli and desi, and pigeon pea, saponins increased (p<0.05) while they decreased in soybean. Tannins enhanced (p<0.05) in chickpea desi, pigeon pea and soybean and reduced (p<0.05) in chickpea kabuli. Furthermore, fermentation enhanced the content as well as estimated bioavailability of minerals. FTIR spectrum of unfermented and fermented legumes showed the presence of several functional groups and modifications in the molecular structure after fermentation. Novelty and scientific contribution. To our knowledge, this is the first study wherein legume (chickpea kabuli and desi, pigeon pea and soybean) fermentation by Rhizopus oligosporus has been assessed for nutritional and antinutritional profile, and FTIR spectra, which concluded that the treatment resulted in an optimal balance of nutrients and antinutrients. The process was established as a potential tool and thus can be proposed in the development of legume based novel functional foods which might help in tackling the concerns of nutritional security.

No abstract

No abstract

No abstract