The effects of certain factors on the properties of yoghurt made from ewe’s milk

Standardized fat content (skimmed, 4.5 and 6.5%) ewe’s milk was used for production of yoghurt and probiotic-fermented milk. The yoghurt was made using a starter culture that consisted of Streptococcus ssp.thermophilus and Lactobacillus delbrueckii ssp. bulgaricus whilst, for the production of probiotic-fermented milk an ABT (S. thermophilus, Lactobacillus acidophilus and Bifidobacterium ssp.) starter culture was used to inoculate the processed milk. All the products were analyzed when fresh and after 7 and 14 days of storage, for the determination of diacetyl, acetaldehyde and free fatty acid contents, as well as pH and titratable acidity. Sensory assessment and firmness of these products were also obtained. The type of starter culture used and the storage time influenced the overall properties of the yoghurt and probiotic-fermented milk products. The fat level in the ewe’s milk significantly influenced the free fatty acid content in the products.