Production of Exopolysaccharides in the Kenyan Fermented Milk, Mursik

Abstract

Exoplysaccharides (EPS) produced by Lactic acid bacteria (LAB) have attracted a lot of interest for application in production of healthy food products since LAB are food grade bacteria and their EPS are natural products. This research aimed to establish whether Mursik, a Kenyan traditional fermented milk product, contained Exopolysaccharides (EPS) and EPS producing Lactic acid Bacteria (LAB). Samples of Mursik were randomly collected from 39 selected homesteads in Njoro Kenya. EPS levels were isolated using alcohol precipitation method and quantified by phenol-sulphuric acid method. EPS producing LAB were screened using sucrose agar and identified by phenotypic and biochemical methods. The data obtained was analysed for variance and means separated by least significance difference. The findings indicate that EPS levels in traditional Mursik differ between households significantly (P< 0.05), and ranged between 17.86 - 59.77 mg/L glucose equivalent (Glu.equiv), average being 44.83 mg/L Glu.equiv. A total of 122 EPS producing LAB were isolated and characterized into five genera namely, Lactococcus (76%), Lactobacillus (11%), Enterococcus (7%), Leuconostoc (5%) and Weissella (1%). Their EPS yields in whey ranged between 44.3 and 449.9 mg/L Glu.equiv. Based on these findings it was concluded that Mursik contains EPS and a variety of EPS producing LAB, predominated by Lactococcus lactis species. It was recommended that Mursik should be developed and utilized as a functional food. EPS producing LAB from Mursik could be developed as starter cultures for improving rheological and functional properties of other fermented milk products.