A Comparative Study Concerned with Generated Folic Acid in Probiotic and Set Yogurt Produced by Milks from Cow, Sheep and Goats

The consumption of probiotic products due to their functional effect on the consumers has been increasing in recent years. One of the effects is the production of B group vitamins, specially folic acid and its derivatives by probiotic bacteria. The aim of this study is to examine the growth rate of folic acid in indigenous set and probiotic yogurt. In order to prepare yogurt, milk samples from cow, sheep and goat were provided and microorganisms consisting of Lactobacillus casei (y2b4, JQ41273501) and ordinary yogurt culture (YC-X11) were employed. The samples were incubated for four hoursat 42oC. Folic acid produced during fermentation and storage for 14 days at 4oC were determined using liquid chromatography (HPLC). Furthermore, acidity and pH changes and sensory scores were determined on the first, 7th and 14th days. The ability of folic acid production by indigenous probiotic in all the milk samples (cow, sheep and goat) were observed. The rate of folic acid produced by probiotic bacteria was more than that of set yogurt (P <0.05). pH changes during storage period has a downward trend while the acidity took an upward trend on the 14th day of storage time (P <0.05). In general this study has indicated that indigenous Lactobacillus casei is able to increase the folic acid rate of production up to three times as compared to that produced by the set yogurt. The inoculation of probiotic had no significant effect on the sensory properties of yogurt and an acceptable product has been produced.