Lactic Acid Bacteria Profile of Fermenting Cucumber in 7% Brine Solution

Abstract

Fermentation was used since ancient times as an easy method of vegetables’ preservation, which also maintains and/or improves the nutritional and sensory properties of vegetables. The aim of this study was to isolate, characterized and identify the lactic acid bacteria (LAB) in spontaneous fermentation of Cucumber. Cucumber samples were purchased from a vegetable stand in Watt market, Cross River State, Nigeria. They were fermented spontaneously for 7 days in 7% brine solution and samples were taken at 24 h intervals for LAB analysis. Thirty bacterial strains were isolated from different phases of the fermentation of cucumber and were characterized by the API 50 CHL System of identification. Three lactic acid bacteria species were identified and included Lactobacillus plantarum, Leuconostoc mesenteroides, and Lactobacillus pentosus. After 24 h fermentation, Leuconostoc mesenteroides was isolated as the dominant LAB specie of the fermentation period. This trend continued until the fourth day where Lactobacillus plantarum became the dominant LAB isolate in the fermenting cucumber. As the fermentation proceeded, Lactobacillus pentosus, was then involved. The results also revealed a decrease in the occurrence of Leuconostoc mesenteroides as the fermentation period increases. The present research thus shows the presence of LAB at different phases of fermenting cucumber. Therefore, the above mentioned isolates could be used as starter cultures for the commercial fermentation of vegetables.