Evaluation of volatile compounds and free fatty acids in set types yogurts made of ewes', goats' milk and their mixture using two different commercial starter cultures during refrigerated storage

► The yogurts with high acetaldehyde had low diacetyl content, pH value and high TA. ► Ewes' milk yogurt contained the lowest amount of acetaldehyde. ► Culture YF-3331 produced both more diacetyl and SCFFAs than culture CH-1. ► The total level of SCFFAs was the highest in ewes' yogurt. ► SCFFAs reached a maximum level at the end of storage while LCFFAs decreased.