Viability of Probiotics in Frozen Yogurt Supplemented with Inulin and Glycerol

Abstract

To evaluate the effect of inulin and glycerol supplementation on the viability of probiotic and yogurt bacterial cultures in frozen yogurt, this study was conducted. The frozen yogurt mixture was prepared with different types of probiotics (<i>Lactobacillus acidophilus</i> and <i>Bifidobacterium lactis</i>) along with commercial yogurt starter culture (<i>Streptococcus thermophilus</i> and <i>Lactobacillus bulgaricus</i>). Different concentrations of inulin (2%, 4%, and 6%) and glycerol (1%, 2%, 3%, and 4%) were also supplemented. The cultural survival rates before and after freezing and with 3 weeks regular intervals up to 12 weeks were examined. The viability loss during freezing process of <i>S. thermophilus</i> and <i>L. bulgaricus</i> were recorded 0.2-0.3 log cycles. While, in probiotic cultures this was observed 0.2-0.5 log cycles in <i>L. acidophilus</i> and 0.1-0.2 log cycles in <i>B. lactis</i> concentration. The glycerol 4% supplementation in this study has shown most significant improvement in viability (P<0.05).