Functional characterization and microencapsulation of probiotic bacteria from koozh

Koozh is a traditional fermented millet beverage unique to south India. Analysis of six market samples of koozh for their microbial profile resulted in 69 isolates of presumptive lactic acid bacteria (LAB). They were grouped as Leuconostoc sp., Enterococcus sp., Streptococcus sp. and Lactobacillus sp. based on morphological characteristics and biochemical tests. Eight among them showed probiotic features: resistance to acid (2.5 pH for 6 h), resistance to 0.3 % ox bile, moderate hydrophobicity (40 %), antibacterial activity against 10 pathogens, susceptibility to 50 % of antibiotics tested. Sequencing of 16srDNA showed them to be five strains of Enterococcus hirae and one each of Enterococcus facecalis, Bacillus amyloliquefaciens and Lactobacillus plantarum. The probiotic isolates were encapsulated in skim milk powder by two different drying techniques: freeze drying and spray drying. The encapsulated probiotic isolates survived both in simulated gastric fluid and simulated intestinal fluid with high cell viability (98–99 %). Storage for 16 weeks at room temperature (27 °C), resulted in 2 log reduction, but better survival with only 1 log reduction was observed at 4 °C and was best at −20 °C. Survival of isolates was similar in both spray and freeze dried products.