부산대학교 도서관

Two forms of probiotic Scallion yogurt as a new dairy probiotic product, with free and microencapsulated bacteria, were produced in the same circumstances. Extrusion method was used for microencapsulation. Pour plate method was used to culture bacteria in MRS-S-agar medium in two replications. The pH value, acidity, fat percentage, protein percentage and dry matter of products were measured according to Iran national standards. Sensory properties were measured by using 32-member taste panel. The results showed that the viability of the free and microencapsulated bacteria reached a 4.61 log cfu g-1 from 8.48 log cfu g-1 and 6.11 log cfu g-1 from 7.82 log cfu g-1 respectably during 42 days. The reduction of bacterial count in the Scallion yogurt containing free cells was significantly (p<0.05) higher than the one containing microencapsulated cells. The acidity and pH measurements showed that the most acidity and the lowest pH value (108.1; 3.88) belonged to the free bacteria sample, and microencapsulated sample had the lowest acidity and the highest pH (99.48; 4.21). Sensory examinations showed no significant differences between two types of Scallion yogurt (p>0.05). Microncapsulation of L. acidophilus with calcium alginate and resistant starch is able to effectively maintain the count of this probiotic high enough for the therapeutic minimum in the scallion yogurt (107 cfu g-1). [ABSTRACT FROM AUTHOR]