Study the viability of Lactobacillus acidophilus in a soy based frozen yoghurt

The frozen dairy desserts matrix might be a good vehicle for probiotic cultures, due to their composition and low storage temperatures. However the viability of these microorganisms may negatively affected by freezing injury and oxygen toxicity on anaerobic probiotics. Frozen yoghurt was prepared by substituting 55% of MSNF with full fat soy flour and Lactobacillus acidophilus (LA-5) cells was added to the mix before freezing. The number of LA-5 cells was enumerated before and after freezing and after 7,15,30,60 and 90 days storage at -18°C and compared with control frozen yoghurt. Freezing caused the number of LA-5 to be decreased by 3.76% and 7.35% in samples with and without soy flour respectively. Viable number of LA-5 after 90 days storage at -18°C in samples with or without soy flour was 8.5×105 and 6.7×105 cfu/g respectively. It was concluded that incorporation of soy flour in frozen yoghurt formulation protected LA-5 cells against freezing injury but had no significant effect on its viability during storage.

کلیدواژه ها:

Frozen yoghurt ، ice cream ، Probiotic ، Prebiotic ، Soy flour