Assessment of nutritional composition and antifungal potential of bacteriocinogenic lactic acid bacteria from 'Kati' against toxigenic Aspergillus flavus

Abstract

In this study, the nutrient contents of "Kati", a fermented cereal-based food, was revealed and antifungal activity of bacteriocin producing lactic acid bacteria (LAB) from "Kati" was assessed against aflatoxigenic Aspergillus flavus (A. flavus). The protein content (9.29%) of "Kati" was higher than (p < 0.05) wet milled-fermented sorghum (6.17%). During fermentation of milled sorghum to ready-to-eat 'Kati', anti-nutrient contents was reduced (p < 0.05) from 1.22 to 0.72 mg/100 g, 3.13 to 1.13 mg/100 g and 7.31 to 3.02 mg/100 g for tannin, phenol and phytates, respectively. Molecular technique revealed the identity of isolated LAB as Lactobacillus pentosus BS MP-10, L. paracasei 4G330, L. brevis ABRIINW, L. casei KG-5, L. sakei strain RFI LAB03, L. fermentum JCM 8607, L. plantarum KLDS 1.0607, L. rhamnosus JCM 8602 and L. lactis XLL1734. Among the isolated LAB, L. plantarum, L. lactis and L. fermentum have significant (p < 0.05) zones of inhibition of 11.0 mm, 9.1 mm and 7.8 mm, respectively, against aflatoxigenic A. flavus. The pronounced antifungal potency of L. plantarum cell free supernatant could be attributed to the presence of 3-phenyllactic acid, benzeneacetic acid, plantaricin (bacteriocin) as revealed by gas chromatography/mass Spectrometry (GC-MS). LAB produced metabolites with antifungal property that contributed to shelf life, flavor and nutrient contents of fermented foods.