Effect of temperature and salt concentration on microbial changes during Tarkhineh fermentation

Abstract

Tarkhineh is a traditional Iranian fermented cereal food produced both commercially and in homes. It is mainly used in the form of a thick and creamy soup consumed at lunch or dinner and is easily digested. In this study, Tarkhineh were fermented at three different temperatures (10, 20, 37) ˚ C and two different salt content of (0.5, 1) %. The purpose of the present study was changes micro flora throughout spontaneous fermentation of Tarkhineh. The results show that the naturally occurring lactic acid bacteria load was found to vary between 1.97×10 5 cfu/gr to 4×10 5 cfu/gr at 10 ˚ C . The yeast and mold counts decrease from 1.04 ×10 5 cfu/gr to 0 cfu/gr at 10 ˚ C. Lactic acid bacteria load was found to vary between 1.97×10 5 cfu/gr to 4.3×10 5 cfu/gr at 20 ˚ C. The yeast and mold counts decrease from 1.04 ×10 5 cfu/gr to 3×10 4 cfu/gr at 20 ˚ C and salt content 0.5%. Lactic acid bacteria load was found to vary between 1.97×10 5 cfu/gr to 1.1×10 6 cfu/gr at 37 ˚ C. The yeast and mold counts decrease from 1.04 ×10 5 cfu/gr to 3×10 4 cfu/gr at 37 ˚ C and salt content 0.5%. The largest increase in the numbers of LAB was noted during the first 24 h of fermentation and further incubation led to decrease. Maximum total acids produced in Tarkhineh at 37 o C. At 37 o C, the optimum ripening period was 1 day. The results show that the temperature and salt content is effective on microbial changes during Tarkhineh fermentation.