The effect of non-standard heat treatment of sheep's milk on physico-chemical properties, sensory characteristics, and the bacterial viability of classical and probiotic yogurt

- Non-standard sheep's milk heat treatment for the production of yogurt was used.
- Classical yogurt and probiotic yoghurt were produced.
- The yogurts showed high content of nutritionally important whey proteins.
- Both kinds of yoghurt presented acceptable sensory evaluation.

Classical and probiotic set yogurt were made using non-standard heat treatment of sheep's milk at 60 °C/5 min. Physico-chemical properties, sensory characteristics, and the viability of bacteria that originated from cultures in classical and probiotic yogurt were analysed during 21 days of storage at 4 °C. For the production of yogurt, a standard yogurt culture and a probiotic strain Lactobacillus rhamnosus GG were used. At the end of storage time of the classical and probiotic yogurt the totals of non-denatured whey proteins were 92.31 and 91.03%. The viability of yogurt culture bacteria and Lactobacillus rhamnosus GG were higher than 106 cfu/g. The total sensory score (maximum - 20) was 18.49 for the classical and 18.53 for the probiotic. In nutritional and functional terms it is possible to produce classical and probiotic sheep's milk yogurt by using a non-standard temperature of heat treatment with a shelf life of 21 days.