Effect of carbon dioxide on sensory attributes, physico-chemical parameters and viability of Probiotic L. helveticus MTCC 5463 in fermented milk

A carbonated probiotic fermented milk using India’s first fully sequenced potential probiotic strain Lactobacillus helveticus MTCC 5463 in a combination with Streptococcus thermophilus MTCC 5460 was prepared and standardized with respect to carbon dioxide pressure, sugar and salt concentrations based on sensory, physico-chemical and microbial parameters. Final optimized product was prepared with 15 % sugar, 0.8 % salt concentration and carbonated at 15 kg cm −2 pressure which was subsequently subjected to shelf life evaluation for 28 days at 5 ± 1 °C. Even though a significant decrease was observed for overall acceptability, the product was acceptable on 28th day of storage. The titratable acidity, pH and tyrosine value has increased gradually while free fatty acids remained unchanged. The viable lactobaciili and streptococci count decreased from 7.84 to 7.54 and 8.94 to 8.87 log cfu mL −1 during 28 days of storage, respectively.