Background: The functions of food has extended from satisfying hunger and providing nutrients to the body, health maintenance, well being and prevention of diseases. Probiotics are such functional food and when they are incorporated to locally available foods, it helps to improve the nutritional profile and therapeutic value. Hence, the study entitled “Process optimisation and quality evaluation of passion fruit and pineapple probiotic drink” was undertaken with the objective of standardising probiotic fruit drink with passion fruit and pineapple and also to evaluate the nutritional and organoleptic qualities of these developed passion fruit and pineapple probiotic drinks.
Methods: In the present study 5 treatments along with one control with 3 replications were standardized. Passion fruit juice (PFJ) was used as the major ingredient and used in varying proportions starting from 50 to 90 per cent with 10 to 50 per cent of pineapple juice (PJ). The best treatment was selected through sensory evaluation along with control by using a score card with nine point hedonic scale. In the selected treatments optimization for the growth of Lactobacillus acidophilus with regard to substrate concentration, time of incubation, temperature of incubation and inoculum concentration were done. The probiotic drinks and their respective controls were then analysed for their nutrient composition like TSS, titratable acidity, energy and ascorbic acid.
Result: Among the various treatments, highest scores for organoleptic qualities was observed in treatment having 70 per cent passion fruit juice and 30 per cent pineapple juice (T³) with a mean score of 8.52 for overall acceptability. The selected juice was optimized for the growth of Lactobacillus acidophilus and had a viable count of 13.38 log cfu ml^-1. The probiotic and non probiotic drinks had TSS content of 12.8 and 13.5° Brix, titratable acidity of 2.28 and 2.03 per cent, energy of 59.32 and 68.96 Kcal and ascorbic acid of 10 and 12.8 mg 100g^-1 respectively.