The effect of tarragon (Artemisia dracunculus) essential oil and high molecular weight Chitosan on sensory properties and shelf life of yogurt

Abstract

This study aimed to investigate the effects of high molecular weight CH and TEO on increasing the shelf life of yogurt as well as improve the consistency and reduce hydration. First, different concentrations of CH (2%, 4%, and 6%) were made and added to yogurt. Then, tarragon essential oil (TEO) was inoculated into yogurt in different concentrations (20, 40, and 60 ppm). The samples were kept at two temperatures, refrigerator and room temperature, for three weeks. Afterward, the effects of different concentrations of CH and TEO on yogurt properties such as pH, acidity, dry matter, fat, protein, syneresis, and the survival of microorganisms such as bacteria, mold, and yeast were investigated. The results showed that CH concentration, temperature, and storage time had a statistically significant effect (ρ < 0.05) on pH, acidity, syneresis, and the bacterial count and yeast. The best results were related to yogurts containing 6% CH with 60% TEO. Nevertheless, samples containing 2% CH had the highest score in sensory evaluation. It is concluded that the addition of high molecular weight CH at a concentration of 6% with 20% TEO leads to the production of high-quality yogurt and greater durability.