Evaluation of Frozen Yoghurt Produced with Vegetable Oils

T HE EFFECT of substituting milk fat with vegetable oils (Sesame, Flaxseed and Olive) at a ratio of 50 and 100%, the characteristics of frozen yoghurt were investigated. Chemical composition, physical, and organoleptic properties were studied in the mix and resultant product. The results showed thatthe values ofpH, specific gravity, and titratable acidityof frozen yoghurt mixes were not significantly affected by the replacement of milk fat with vegetable oils(p ≤ 0.05). When the substituted by 50% of milk fat in frozen yoghurt mixes was swapped out for flaxseed oil, their apparent viscosity and freezing point significantly decreased, but their whipping ability significantly improved (p ≤ 0.05). The same tendency was seen when olive oil was used in place of milk fat. When milk fat was replaced with 100 percent flaxseed oil, the apparent viscositydecreased noticeably. In contrast, frozen yoghurt manufactured with sesame oil showed no discernible effect on titratable acidity or pH values as well as the specific gravity of final frozen yoghurt (p ≤ 0.05) When 50% of the milk fat was substituted by olive oil, the freezing point and apparent viscosity of the frozen yoghurt were dropped, but their overrun was decreased. The obtained frozen yoghurt containing 50 or 100% olive oil showed the lowest overrun value and melting resistance among all frozen yoghurt. However, replacing the milk fat with sesame oil increased the melting resistance of the resultant frozen yoghurt. The lowest organoleptic ratings were achieved with flaxseed substitution 50 and 100 %levels, which resulted in an oily test and a weak body of frozen products.At 50% replacement ratio for sesame oil recorded the highest sensory scores, which were confirmed by all the opinions of the arbitrators.