VIABILITY OF LACTIC CULTURES BEFORE AND AFTER FREEZE DRYING IN POMEGRANATE JUICE

Abstract

The purpose of this research was to study the viability of lactic cultures in pomegranate juice before and after freeze drying.Two dietary adjuncts of a combination of 50% pomegranate juice and 50% skim milk were fermented separately with 1% culture of Lactobacillus plantarum and Lactobacillus casei and freeze-dried. The viability of the freeze-dried strains was evaluated after 24 h on MRS agar. Results indicated a 2 log reduction in the viability of lactic cultures in fermented combination of pomegranate juice and skim milk and also in fermented skim milk (control) after freeze-drying . The viable count of L.casei after freeze drying was reported as 8.04±0.1470log 10 cfu/ml and 8.030± 0.1483log 10 cfu/ml in control and pomegrante juice and skim milk mixed sample respectively . The viable count of L. plantarum after freeze drying was reported as 8.04±0.1470log 10 cfu/ ml and 8.02±0.0151log 10 cfu/ml in control and pomegrante juice and skim milk mixed sample respectively . Survival of the lactic cultures were studied after freeze drying at intervals of 7 days, 15 days, 30 days and 90 days of storage under refrigeration conditions. A higher percent of survival was noted upto 30 days in both the lactic organisms in skim milk (control) and fermented combination of pomegranate juice with skim milk . However there was a reduction in viability of both the cultures on the 90th day of enumeration.