Screening Lactic Acid Bacteria for Improving the Kanom-jeen Process

Abstract

The research objective was to select lactic acid bacteria (LAB), which had been isolated from rice slurry in the Kanom-jeen process, for use as a starter culture. Samples of fermented rice, sedimented flour and drained wet flour taken from the Kanom-jeen production process produced 330 presumptive isolates of LAB. The isolates produced 287 strains that were gram positive and catalase negative, which could be categorized into four groups by their gas production ability and cell morphology: homofermentative rod (77.35%), homofermentative cocci (11.20%), heterofermentative rod (0.35%), and heterofermentative cocci (11.55%). The largest population, homofermentative rod (221 strains), was chosen to be clustered with SPSS ver.10.0 using starch hydrolysis activity and acid productivity. From the cluster results, P1 and P39 showed the highest acid productivity (0.91 and 0.86%, respectively) with the largest starch hydrolysis zone (1.4 and 1.2 cm, respectively). After testing P1 and P39 with API 50 CHL, both strains were identified as Lactobacillus plantarum. To study their fermentation ability and effect on the physical properties of Kanom-jeen samples, both strains were separately used in producing Kanom-jeen compared with the commercial process. Results showed that the fermentation time (the time required for acid titration to reach 0.95% lactic acid or higher) of Kanom-jeen with P1 was the shortest (24 h). However, the tensile properties in Kanom-jeen made with P1, P39 or the commercial process were not significantly different (p> 0.05).