PRODUCTION OF PROBIOTIC FRUIT JUICE (ORANGE AND WATERMELON) USING LACTIC ACID BACTERIA ISOLATED FROM FRESH COW MILK

Abstract

Probiotication of fruit juice by Lactobacillus sp is an essential component of the human diets in the food industry. This study is focused on the production of probiotic fruit juice from orange and watermelon. Probiotic viability, physicochemical (titratable acidity, total soluble solid, pH and reducing sugar), antimicrobial activity and sensory evaluation of the fermented and stored probiotic orange and watermelon juice using lactic acid bacteria (LAB) (Lactobacillus plantarum strain MerLAB1and Lactobacillus paracasei strain MerLAB2) as single and mixed (consortium) starter was investigated. Results revealed that there was an increase in the number of lactic acid bacterial count (0.09 - 3.37 ×106 CFU/mL), titratable acidic % (0.030-0.050) and reduction in pH (4.28-3.97), reducing sugar ºB (4.49-3.49) and total soluble solid (4.12-3.81) during fermentation. Lactobacillus plantarum and Lactobacillus paracasei mixed culture (T3) probiotic juice samples had the best antagonistic activity against the pathogenic test organism (Escherichia coli) with an inhibition zone of 30mm after 72 hours of fermentation. The probiotic LAB were viable throughout the storage time of 4weeks at 4 ºC with the cells of 1.00±0.00 10×109 CFU/mL in the juice sample. There was no significant difference at P ≥ 0.05 in terms of sedimentation, aroma, colour, or appearance during the time of storage. The orange and watermelon juice supported the viability, lactic acid production, and the antagonistic potential of the probiotic candidate. This study suggests that the production of fruit juice supplemented with Lactobacillus plantarum strain MerLAB1and Lactobacillus paracasei strain MerLAB2 is essential in the food industry.