Effect of Khalvash (Mentha piperita) Extract on the Physicochemical, Sensory and Microbial Characteristics of Doogh During Shelf Life

Background and Objective: Natamycin is generally used to control mold and inhibit yeast growth and some bacteria. However, there is an increased sensitivity for using natamycin. The study aimed to investigate the effect of khalvash (Mentha piperita) extract on doogh. Materials and Methods: The extracts of khalvash were used at levels of 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 with the control sample as well as the sample containing natamycin in the doogh. Sampling was carried out on the 1st, 15th and 30th day in three replications and its effect on physicochemical properties including pH, acidity, fat, dry matter percentage and microbial properties including mold and yeast count and sensory characteristics were investigated. Results: There was a significant difference between the pH factors in the control group and the natamycin three times (days 1, 15 and 30) (p<0.05). The level of anti-microbial activity increased in the treatments with kalvash extracts in comparison with the treatment with natamycin and control during the period (p<0.05). An increase in acidity helped increase the antimicrobial activity of the extract. The treatments with extract had significant differences from the control treatment (p<0.05). In addition, the results of the sensory evaluation indicated that the highest and lowest rates of acceptance were in the doogh with natamycin and 0.3% khalvash, respectively. Likewise, an increase in the level of khalvash extracts resulted in a decrease in the acceptability level reaching its lowest level in the treatment of 0.3% (p<0.05). Conclusion: The use of khalvash extracts can be a suitable flavor and a fairly appropriate preservative in the doogh.