IMPROVING SURVIVAL OF CULTURE BACTERIA IN FROZEN DESSERTS BY MICROENTRAPMENT

Lactobacillus bulgaricus cells were entrapped in beads of calcium algi nate and evaluated for their ability to survive freezing processes. Ce lls survived freezing (without agitation) in ice milk mix much better than in distilled water, and more entrapped cells survived than did ce lls that were not entrapped. Glycerol and mannitol were cryoprotective , but glucose was not, when each was added (6%) separately to the bead s. Entrapment protected the lactobacilli in batch frozen and continuou sly frozen ice milk mixes. The percentage of survival for entrapped an d unentrapped cells in continuously frozen ice milk approximated 90 an d 40%, respectively. Lactobacilli survived better in beads with mean d iameters >30 mum than in those averaging 15 mum. Addition of entrapped lactobacilli had no measurable effect on the sensory characteristics of the ice milk.