The Effect of Heat Inactivating Process on Biochemical, Microbiological and Sensory Characteristics of Iranian Drink Based on Fermented Milk (Doogh)Elaheh Ahmadi1*, Amir Mohammad Mortazavian2 and Reza Mohammadi2
2Department of Food Science and Technology, Faculty of Nutrition Sciences, Food Science and Technology/ National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, P.O. Box 19395-4741,Tehran, Iran
- *Corresponding Author:
- Elaheh Ahmadi
Young Researchers and Elites Club
Science and Research Branch
Islamic Azad University, Tehran, Iran
E-mail: [email protected]
Received date: August 16, 2013; Accepted date: September 27, 2013; Published date: October 08, 2013
Citation: Ahmadi E, Mortazavian AM, Mohammadi R (2013) The Effect of Heat Inactivating Process on Biochemical, Microbiological and Sensory Characteristics of Iranian Drink Based on Fermented Milk (Doogh). J Food Process Technol 4:271. doi:10.4172/2157-7110.1000271
Copyright: © 2013 Ahmadi E, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
This study investigates the effects of heat inactivating processing of yogurt bacteria compared with other sequential inoculation on biochemical, microbiological, and sensory characteristics of typical Iranian drink based on fermented milk (Doogh). The yogurt bacteria (Streptococcus thermophilus and Lactobacillus delbrueckiis sp. bulgaricus) were used in all treatments. Bifidobacterium animlis spp. lactis PTCC 1631 was used as probiotic bacteria. A pH, titrable acidity, redox potential, fermentation time, and viability of probiotic organisms were analyzed during fermentation and over the refrigeration storage for21 days at 5°C. Also, the sensory attributes of treatments were determined at the end of fermentation. The greatest (p<0.05) mean pH drop rate was observed in BlY-40-4.5 treatment (B. animlis spp. lactis PTCC 1631 was co-cultured with yogurt starter bacteria and incubated at 40°C until final pH 4.5).In addition, the greatest viability of bifidobacteria was observed in this treatment. The viability of bifidobacteria strains was significantly higher in heat inactivating treatments than non-heat treated treatments. This process didn’t have positive effect on sensory properties of Doogh. The most acceptability in taste, texture, and mouth feel and appearance tolerability were observed in co-culture treatment in this study.