Surviving of Probiotic Bacteria Lactobacillus casei and its Effect on the Quality and Sensory Evaluation of the Iranian White Cheese Produced by Ultrafiltration Technique

The survival of the probiotic strains Lactobacillus casei (ATCC 39392 Collection, Australia) was investigated in the Iranian white cheese produced by ultrafiltration technique. Four treatments of UF Iranian white cheese were produced: control I (C1), with a commercial starter culture mix including Lactoccocus lactis subsp. cremoris, Lactococcus lactis spp diacetylatis), control II (C2), with commercial starter culture mix and the probiotic L. casei, LC with a commercial starter culture mix and probiotic L. casei (uncapsulated) and LCC with commercial starter culture mix and probiotic L. casei capsulated with Sodium Alginate by extrusion method. The cheese samples were ripened at 8-12 oC for 60 days and the viability of cultures and also moisture, salt, protein, fat in solids, pH were determined biweekly. Cheese samples also were analyzed for sensory evaluation at the end of 60 days of ripening. At day 1, the log10 numbers of L. casei in the samples C2, LC and LCC were 8.61, 8.60 and 8.69 cfu g-1 respectively. These figures reached to log10 6.57, 7.01 and 8.20 cfu g-1 after 60 days of storage, respectively. The reduction was significant (P>0.01). The final numbers of L. casei, in all of the cheese samples were greater than the minimum numbers of the recommended therapeutic products (106-107 cfu /g). Moisture content and pH of all cheeses were decreased and salt and protein content increased during ripping, while the fat in Dry matter (FDM) content of all cheese were not change significantly during storage (P <0.01). The maximum and minimum range of loss of moisture at the end of ripening period was 6.1 and 3.34 % which belonged to LCC and C1 respectively. Therefore it was concluded that the type of starter affects the moisture content. The maximum and minimum range of loss of pH at the end of ripening period belonged to C1 and LC respectively and the loss of pH in the LCC was the least (9.26%). The sensory evaluation showed that there was no significant difference between the experimental samples from a texture and flavor point of view. While C2 acquired the high score of texture and flavor but not significantly. Therefore probiotic Lb. casei both form free and microencapsulated can be used successfully in Iranian white cheese produced by ultrafiltration technique without adversely affecting the cheese quality during ripening. Also L. casei can be use as starter culture in the Iranian white cheese produced by ultrafiltration technique.