| Abstract: |
The effect of substituting milk fat by different vegetable oils and three emulsifiers on the quality of white soft cheese was studied. Three vegetable oils (sunflower oil, soybean oil and canola oil) were used as a substitutes of milk fat, 4% of each vegetable oil was added to fresh skim milk. Three emulsifiers were also used; 1% of whey proteins concentrate (WPC), 0.1% of distilled mono glyceride (DMG) or 0.1% of glycerol mono stearate (GMS) in the manufacturing of soft cheese. Cheeses were analyzed for chemical analysis, oxidative stability, microbiological examination and organoleptic properties, when fresh and after 1, 2 and 3 months of storage at 7±1ºC. Results showed that using of WPC as emulsifier matter decreased the loss of oil in cheeses whey comparing with the other two emulsifiers. Cheese made with sunflower oil and WPC was the most stable for oxidation stability and recorded high scores for sensory evaluation than the other treatments. On the other hand, cheeses containing canola oil were less acceptable because of its oily flavour. Four mixtures of the three vegetable oils were prepared (sunflower: soybean 1:1, sunflower: canola 1:1, soybean: canola 1:1 and sunflower: soybean: canola 1:1:1) and 4% of each oils mixture was added to skim milk before cheese making. The emulsifier WPC was added with a level of 1% to all treatments. Resultant cheeses were analyzed when fresh and after 1, 2, 3 months of storage at 7±1ºC. Results showed that all treatments were more acceptable than cheeses of the first experiment. Due to oil oxidation in some treatments, three natural antioxidants (2% of potato peels extract, 5% of green pepper juice and 1% of guava leaves extract) were used in these cheeses making to improve their oxidative stability.from the results obtained from this work, we recommended that we can produce an imitation functional soft cheese using sunflower oil, soybean oil or canola oil as milk fat substitutes with using emulsifiers especially WPC which improved the quality of the resultant cheeses. Also we recommended that, potato peels extract, green pepper juice or guava leaves extract could be used as natural antioxidants in cheeses manufacturing to improve its oxidative stability.
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