Growth of Bifidobacterium longum BB 536 in banana beverage and strain survival during the refrigeration storage of the fermented beverage

Abstract

This study was carried out to develop safe probiotic fermented banana beverages. Different stages of banana were peeled, 10% (W/V) pulp was blended, cooked, cooled to room temperature, and malted rice flour was added and mixed well to obtain the beverage. Moreover, 10% skim milk was prepared to obtain the re-constituted skim milk. Beverages were sterilized (121ºC for 15 minutes), cooled (37ºC), and inoculated with 3% active Bifidobacterium longum BB 536 culture followed by incubation at 37 º C for 48 hours to obtain the fermented beverage. Fermented samples were drawn for analysis of Bifidobacterium viable cells, pH, TSS, moisture content, and microbiological safety. Bifidobacterium longum BB536 significantly (p < 0.5) increased by fermentation continuation in all beverages as compare to strain essential levels at the beginning of fermentation. The viable number of strain BB 536 at maximum growth (36 h) was more than 6 log CFU/ml (the number required to fulfill probiotics product) in all fermented beverages; except ripe banana beverage and that may be due to its high starch content as compared with medium over ripe and over ripe banana. On the other hand, TSS significantly (0<-0.5) decreased due to metabolic activity of strain BB 536 and break down of some macro-components. During growth acids were produced results in significant (0<-0.5) decreased of pH. While moisture significantly (0<-0.5) decreased by increase in strain biomass. Yeast and ix Mould, Fecal Streptococcus, Staphylococcus Aurous, and E. Coli, were not found in all strain BB 536 fermented beverages. Moreover, salmonella was not detected in any of the fermented beverages. The absence of these pathogenic bacteria is due to the bifidogenic affect of strain BB 536. Therefore, formulation of safe strain BB 536 fermented banana beverage is successful. On the other hand, the strain BB 536 survived for the first week of storage in all fermented beverage to a level fulfil the requirement of probiotic products. Moreover, it survived for two week in fermented reconstituted skim milk and medium over ripe banana beverages recording viable counts of 6 log CFU/ml and 6.11 log CFU/ml, respectively.