摘要：Frozen yoghurt can be regarded as a healthy alternative to plain ice cream. This study investigates the isolation and identification of beneficial bacterial isolates from Laban Rayeb. Three isolates were selected and identified, namely Lactobacillus acidophilus r1, Lactobacillus acidophilus r2 and Latctococcus lactis subsp lactis r3. Also results showed that Laban Rayeb isolates had an inhibition and bactericidal effects on the growth of some pathogenic microorganisms as Staphylococcus aureus; E.coli ATCC 25922 and Bacillus subtilis NCIB3610. Antagonistic effect of S. aureus and E.coli indicated more pronounced inhibitory effect than Bacillus subtilis especially for Lactobacillus acidophilus r2. Then Low-fat ice cream mix was fermented with probiotic supplemented; omega-3 & vitamin E with traditional starter culture and evaluated for culture survival, composition, and sensory characteristics of frozen product. The developed frozen yoghurt formulae were as follows: Formula 1 with no probiotics, Formula 2 containing 3%w/w of Lactobacillus acidophilus r2 which has shown significant promise in all probiotics characteristics, and Formula 3 containing 3% w/w of probiotic strain (Lactobacillus acidophilus r2); with 2% ω-3 with vitamin E. The survival rate of probiotic in Formula 2 and Formula 3 after 4 weeks was higher than 106 CFU/ ml, the number regulated by FDA for the probiotic products. Formula 3 was containing 39.13±1.13 μg/ g alpha tocopherols after 4 weeks under freezing conditions. Sensory evaluation was carried out among 10 panelists, using the 9-point hedonic scale method for food acceptance. Formula 1, 2, and 3 obtained the mean score of 7.45, 7.98 and 8.01, respectively.
