Formulation, Processing and Characterization of Fermented Probiotic Mango Juice Using Selected Starter Cultures

Abstract

Probiotics are live microorganisms added to food products to confer health benefits such as gut health, cancer protection and improved immunity when consumed. Fruits juices are considered as potential channels for delivering probiotics as they contain essential nutrients and low pH suitable for the growth of probiotics. The study was undertaken to formulate, process and characterize fermented probiotic mango fruit juice using three different mixed lactic acid bacteria cultures: Abt-5® culture (Streptococcus thermophillus, Bifidobacterium and Lactobacillus acidophilus); Fiti® culture (Lactobacillus rhamnosus GR-1) and Yo-mix® culture (Streptoc.occus thermophillus and Lactobacillus delbruikii ssp bulgaricus). The viability of the cultures was also assessed. The mango juice was formulated using mango pulp to water ratios of 100:0, 25:75, 50:50 and 75:25 (v/v) and adjusted to 17° brix by adding cane sugar. The formulated mango juices were pasteurized at 90 °C for 1 minute and cooled to 10 °C. Sensory evaluation was carried out to determine the most preferred formulation of the fruit juice before fermentation. The preferred mango juice samples were cooled to 402 °C and incubated with the three different mixed bacteria cultures (1 g/l) for 0, 12, 16, 24, 36, 48 and 72 hours. The final product stored at 4 °C. Analysis for sensory evaluation, culture viability, pH, total soluble solids (TSS) and total titratable acidity (TTA) was done. The 50:50 ([mango pulp: water) mango fruit juice formulation was significantly different (p<0.05) from the other samples in consistency and was rated the best in overall acceptability. There was general increase in cell count in all cultures with mango juice fermented with Lactobacillus rhamnosus GR-1 for 48 hours recording the highest viable cell count of log10 9.14 CFU/ml. Highest pH decrease was observed in 50:50 formulation with significant (p<0.05) increase in TTA from 0.15% to 0.69% using Lactobacillus rhamnosus GR-1 within 72 hours. Subsequently, the TSS decreased from 17° brix to 14.47° brix. The study showed that the three mixed were able to utilize nutrients present in the formulated mango juice during fermentation as demonstrated by decrease in pH and TSS. The study therefore recommends that further research should be done on the probiotic fermented mango juice to determine the change in physco-chemical characteristics and culture viability during storage.