Potassium sorbate and sodium benzoate levels in doogh samples consumed by the Tehran market measured using high performance liquid chromatography

Doogh is a fermented dairy product that is a national beverage in Iran. Considering the national importance of doogh and increased consumption in the population، the use of preservatives (sorbate and benzoate) to extend the shelf life of the product and reduce the microbial load should be controlled to guarantee the health of consumers. This study determined the amount of potassium sorbate and sodium benzoate in the doogh distributed in the city of Tehran. Factors affecting the potassium sorbate and sodium benzoate extraction from doogh (pH of the sample، the extraction solvent volume، amount of Carrez solution and speed of centrifuge) were optimized. Approximately 90 experiments were analyzed in the laboratory to optimize the effective parameters for extraction efficiency. Then 60 non-carbonated heated doogh samples were selected from the Tehran market during the summer season. The samples were analyzed using high performance liquid chromatography (HPLC) for 3 consecutive summer months after optimization. The data was analyzed with SPSS V. 16. 0. The method proposed in this study was significantly less time-consuming than other techniques. It had the advantages such as acceptable accuracy، precision and elimination of interruptions in the samples. The results show there was no significant difference (p<0. 05) between potassium sorbate and sodium benzoate in the samples supplied in Tehran during the summer. There were significant differences between samples (p>0. 05) for potassium sorbate and the means of samples were not significantly different (p<0. 05) for sodium benzoate. Samples 10 and 7 showed maximum potassium sorbate and sodium benzoate concentrations of 267. 8 and 49. 3 mg/kg، respectively. Samples 16 and 2 showed minimum concentration values of 8. 2 and 4. 6 mg/kg، respectively. Although there is a limited consumption rate for potassium sorbate and sodium benzoate in doogh، these preservatives are used in most doogh distributed in Tehran. The results of this study can be effective for standardization of a limited consumption rate for potassium sorbate and sodium benzoate in this product.