Antimicrobial Activity of Some Allium Extracts on Microorganisms Associated With Soybean Daddawa Spoilage

Abstract

Microorganisms associated with deterioration of Spontaneously Fermented Soybean Daddawa (SFSD) were isolated, classified and their enzyme profiles determined. The inhibitory activities of aqueous and ethanol extracts of three Alliums: garlic, onion and leek (3, 5 ad 7 % concentration) on the identified isolates were also assessed. Bacillus, Staphylococcus, Lactobacillus, Candida and Cryptococcus spp. were found to be associated with SFSD spoilage. All these isolates demonstrated activities of six to eleven different enzymes. High alkaline phosphatase and leucine arylamidase activities characterised all isolates. The esterase activities of the yeasts strains were higher than those of Bacillus and LAB strains. Extracts of all tested Allium spp. demonstrated significant (p < 0.05) abilities to arrest proliferation of the isolated organisms. These activities were Allium-type and concentration-dependent, with garlic at the highest extract concentration (7%) exhibiting the most significant (p < 0.05) inhibitory activity. The high levels of alkaline phosphatase, leucine arylamidase and esterase activity have implications on soybean daddawa spoilage. The results indicate that Allium spp., especially garlic, could be exploited in the preservation of soybean daddawa.

Keywords: Condiment, Garlic, Leek, Onion, Preservation, Soybean daddawa