CHARACTERISATION OF LACTIC ACID BACTERIA ISOLATED FROM KEFIR MILK MADE FROM DAIRY AND NON-DAIRY SOURCES AND THEIR SENSORY ACCEPTANCE

Abstract

Kefir is fermented milk obtained by fermenting milk with kefir grains. Chemical composition from dairy and non-dairy sources may affect the growth and characterisation of lactic acid bacteria (LAB). In this study, different sources of milk (cow milk) and non-dairy milk (soymilk and coconut milk) were used as fermentation media for kefir products. The objectives of the study were to isolate and characterise LAB from Kefir drink using dairy and non-dairy milk. LAB were isolated using different cultural methods such as MRS Agar, MRS with 0.8% CaCO3 and M17 Agar. The characteristics of LAB isolates were determined using morphological, biochemical tests and API 50 CHL Kit. Sensory evaluation of the sample of kefir drinks was also determined. Results confirmed that the isolates identified were Lactobacillus buchneri, Lactobacillus brevis 1, Leuconostoc mesenteroides, Lactobacillus acidophilus 3 and Lactobacillus plantarum 1. The L. buchneri, L. brevis, Leu. mesenteroides and L. acidophilus are heterofermentative bacteria, whereas, L. plantarum is homofermentative bacteria. Four LAB isolates have the potential to be used as probiotic strains due to their high resistant to pH and bile salt. The sensory score of these products in the range of 5.00 to 8.00 in nine point hedonic scale. Most of the sensory panelists preferred cow milk (p < 0.05) than coconut milk kefir and soy milk kefir in the sensory evaluation in all attributes. Meanwhile, the preference between coconut milk kefir and soy milk kefir was similar (p>0.05) in all attributes. Therefore, this study will provide benefits to probiotic manufacturers to produce alternative probiotic drink using dairy and non-dairy milk.