Investigation of physicochemical, microbiological and sensory properties of fermented milk beverages containing paraprobiotics produced with different probiotic bacteria

In this study, six different fermented dairy beverages, containing and not containing paraprobiotics, were produced using Lacticaseibacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis BB12 strains. The fermented milk beverages were stored at 4°C for 30 days, and their physicochemical, microbiological, and sensory properties were examined during the storage period. The pH, titratable acidity and exopolysaccharide values of fermented milk beverages ranged between 3.52-4.52, 0.71-1.58%, and 1.02-1.63 g/kg, respectively. The exopolysaccharide content of fermented milk beverages produced using B. animalis subsp. lactis BB12 was higher than that of fermented milk beverages produced with L. rhamnosus GG. The apparent viscosity values of fermented milk beverages ranged between 0.146-0.179 Pa.s, flow behaviour index values ranged between 0.27-0.34 and coefficient of consistency values ranged between 1.32-2.17 Pa.s. The radical scavenging activity and antioxidant capacity values of fermented milk beverages were determined as higher in fermented milk beverages produced by adding paraprobiotic before incubation compared to the samples produced without paraprobiotic and after incubation by adding paraprobiotic. Although the counts of L. rhamnosus GG and B. animalis subsp. lactis BB12 in fermented milk beverages decreased due to the extension of storage time, the level of 8 log cfu/g was found in all fermented milk beverages. Fermented milk beverages showed antibacterial activity against Bacillus cereus NCTC 9946, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 35218 and Salmonella enterica subps. enterica DSM 18522 pathogenic strains. The appearance, taste, texture and general appreciation scores of fermented milk drinks ranged between 5.07-7.57, 5.07-6.86, 4.71-7.50, 4.78-7.14, respectively, and the highest general appreciation scores were the fermented milk drinks produced with B. animalis subsp. lactis BB12.