| 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). |