Identification of subdominant lactic acid bacteria in dawadawa (a soup condiment) and their evolution during laboratory-scale fermentation of Parkia biglobosa (African locust beans)

Abstract

The successive colonization of fermenting African locust beans (Parkia biglobosa) by lactic acid bacteria (LAB) was investigated for seven days. The LAB isolated were Pediococcus pentosaceus, Lactobacillus raffinolactus, Leuconostoc mesenteroides, Leuconostoc sp, Pediococcus halophilus,
Pediococcus sp, Lactobacillus sp, Lactobacillus plantarum, Lactobacillus acidophilus and Lactobacillus brevis. The first dominant species were P. pentosaceus, which was more in abundance, L. raffinolactus, L. mesenteroides and another Leuconostoc sp. At the end of fermentation, a stable community comprising of P. halophilus, P. pentasaceus and L. brevis was formed. The dominant genera in this study were Lactobacillus and Pediococcus. The proximate analysis of the fermenting and
fermented mash showed an increase in moisture content from 55.1 to 65.2%, pH from 6.25 to a stable alkaline value of 8.4. The reducing sugar however, decreased from 0.96 to 0.58 mg. The amino acid content increased from an initial value of 8.13 to 35.55 mg for the laboratory-scale product, whereas the value of the control was 13.4 mg. The total viable count increased from an initial value of log102.6 to log105.8 and then fell to a final value of log104.1. The enterococci count increased initially but eventually fell to zero. The total yeast count increased initially from log105.3 to log106.6 and thereafter fell to zero. The market sample had a value of log101.5. No coliforms were found in the course of fermentation as well as in the final product of the laboratory-scale experiment and the market sample.