Investigation on the Effect of Milk Type and Fermentation Time on the Physicochemical, Sensorial and Rheological Properties of Shiraz (Siraj) Ccheese

Due to the climate variation and extension of traditional animal husbandry in Iran, investigation on the physicochemical, microbial and technological characteristics of different kinds of traditional cheese is crucial. In this study, the effect of milk type and fermentation time on the physicochemical, sensorial and rheological properties of Shiraz cheese- soft cheese produced in western Iran- were investigated. Shiraz traditional cheese was produced from bovine and ovine milk with 4 and 6 hour fermentation times. The physicochemical, rheological and sensorial properties of the cheese samples were analyzed with completely randomized design with three replicates.. According to our results, when fermentation time increased, the amount of protein, fat, dry matter and pH of the cheese samples was decreased. Shiraz cheese produced from ovine milk has higher protein, fat and dry matter than bovine cheese. Rheological tests showed that storage modulus (Ǵ) and loss modulus (G̋) of the ovine Shiraz cheese samples were higher than those of bovine samples in each frequency, and when the fermentation time was increased, storage and loss modulus were increased too. The sensorial characteristics –taste and texture- of the ovine Shiraz cheese were improved significantly when the fermentation time was increased. The results showed that the physicochemical, rheological & sensorial properties were affected by the milk type and fermentation time. Ovine Shiraz cheese with 6 hours fermentation had firmer and better texture than bovine Shiraz cheese.