VIABILITY OF BIFIDOBACTERIUM-BIFIDUM AND ITS EFFECT ON QUALITY OF FROZEN ZABADY

It has been made possible to make a good quality frozen Zabady with Bi fidobacterium bifidum. Normal Zabady culture was replaced at the rate of 33% and 50% with either Bifidobacterium bifidum DI (D-1 and D-2) or Bifidobacterium bifidum BB12 (H-1 and H-2), respectively, during the manufacture of Zabady (set-type yoghurt) from which frozen Zabady was made. Neither the strain nor the amount of bifidobacteria affected sig nificantly (P>0.05) the specific gravity and weight per liter of mixes . Mixes made with bifidobacteria had higher freezing point and pH valu es, and lower acidity. This decrease or increase was proportional to t he amount of added bifidobacteria. Adding bifidobacteria increased the overrun, melting resistance and improved the organoleptic properties of the resultant frozen Zabady. Although all frozen Zabady were accept able over 5 weeks frozen storage, samples made with bifidobacteria wer e more acceptable. Frozen storage for 5 weeks did not significantly (P >0.05) affect pH, titratable acidity, total solid content and organole ptic properties of frozen Zabady. The survival of bifidobacteria incre ased as the amount of added bifidobacteria increased. The number of bi fidobacteria decreased at a different rate throughout the storage peri od. Treatments made with 50% bifidobacteria had the highest survival r ate, while treatment made with normal culture had the lowest survival rate. The numbers of bifidobacteria which survived even after 5 weeks of frozen storage in frozen Zabady made with bifidobacteria (>10(7)) w as higher than the minimum level that should be present to achieve the beneficial effect of bifidobacteria (10(5) to 10(6) ml(-1)). Therefor e frozen Zabady could be used as a good source for this probiotic bact eria. Total bacterial counts decreased as the storage period progresse d. The decrease of total bacterial counts increased as the amount of a dded bifidobacteria increased. Copyright (C) 1996 Canadian Institute o f Food Science and Technology.