Survival of probiotic bacteria in ice cream from concentrated yogurt and kefir

Abstract

Probiotic microorganisms are beneficial to the body, especially the gastrointestinal system, for they help maintain the intestinal balance and eliminate microorganisms that may adversely affect the body. The aims of this study were to examine the survival of microorganisms that were selected as probiotics in ice cream made of concentrated yogurt and concentrated kefir and to develop these ice cream products that have sufficiently high numbers of probiotic or beneficial bacteria. Survival of probiotic bacteria, including Bifidobacterium bifidum B4140, Lactobacillus caseinsubsp. casei B1922 and Leuconostoc mesenteroides TISTR473, in yogurt ice cream in relation to milk fat contents and types of sweeteners, and total microorganisms in kefir ice cream were studied. The results showed that B.bifidum B4140, L. casei B1922 and L. mesenteroides TISTR473 in the yogurt ice cream product that was stored at -20 °C for 90 days had average survival percentages of 56.15-74.77, 63.90-78.64, and 66.62-66.76, respectively. The milk types (the fat contents in the milk) and the types of sweeteners did not seem to have a significant effect on survival of the probiotic L. casei and L. mesenteroides, but a possible effect from sweeteners on survival of B. bifidum was noted (p ˂ 0.05). Overall, the process for production of ice cream from concentrated yogurt from whole or skimmed milk and natural sweeteners were developed. The processes supported survival of probiotics in yogurt ice cream and live bacteria in kefir, which survived at acceptably high numbers, ≥6 log CFU/ g, in these products after 3 months of frozen storage.