The antimicrobial effect of sumac (Rhus coriaria L.) powder on E.coli and Penicillium notatum in prebiotic low fat yoghurt.

Abstract

Introduction: Increased foodborne diseases and food poisoning, as well as its health problems, have led to the development of studies on the use of new antimicrobial agents. Functional foods are the topic of interest in this regard. Among the functional foods, natural food additives have attracted the attention of consumers. Objective: The purpose of this study was to investigate the effect of sumac powder as an antioxidant and antimicrobial compound against E.coli and Penicillium notatum in low-fat prebiotic yoghurt. At the same time, by improving the sensory properties of the product, a step towards increasing the health of the community and the production of novel products using a natural additive. Materials and Methods: In order to evaluate the anti-oxidant, anti-microbial, physiochemical and sensory properties, sumac powder (0%, 1%, 1.5% and 5%) of prebiotic (Resistant starch type 2) low fat yoghurt and examined for 28 days storage at 4˚C. To evaluate the antimicrobial effects of sumac powder, surface cultivation method was used. Also, anti-oxidant activity of 312, 500, 625, 1000, 1250 and 2500 ppm concentrations of low-fat prebiotic yoghurt containing (0%, 1%, 1.5% and 5%) were prepared and measured by DPPH method. All tests were performed in 3 replications. Statistical analysis was performed using SPSS software. Significant statistical differences were also determined at the level of 0.05. Results: The titratable acidity of yoghurt containing sumac powder increased with increasing the amount of sumac powder, while the pH of yoghurt decreased. The antioxidant activity of yoghurt samples also increased significantly with increasing the percentage of sumac powder from 0 to 5% (p <0.05). Different consentrations of sumac powder during 28 days of cold storage reduced the amount of E.coli and Penicillium in low-fat prebiotic yoghurt. Conclusion: The results obtained in this study showed that sumac powder with high antioxidant and antimicrobial properties can be used in the food and pharmacology industry. Adding 5% sumac make the best taste in low-fat prebiotic yoghurt. Therefore, the addition of sumac powder in low fat yoghurt formulations can improve the antioxidant and antimicrobial effects as well as reduces E.coli and Penicillium counts.