The effect of propolis extract on physicochemical, sensory and microbial characteristics of synbiotic yogurt inoculated with Lactobacillus casei.

Dairy products such as yogurt are considered as one of the most popular foods in the world. Beside the probiotics, functional ingredients such as prebiotics are also used in various products. One of the functional ingredients is propolis which has antioxidant, anti-inflammatory, antifungal, anti-viral and anti-tumor properties, and in addition to this properties it can be a prebiotic which can have beneficial effects on the human digestive system. This study was conducted to investigate the effect of propolis extract on the physicochemical, sensory and microbial characteristics of synbiotic yogurt inoculated with Lactobacillus casei. This study was conducted in five treatments (control (A), 1% (B), 2% (C), 3% (D), 4% (E)) and three replications. Physical and chemical properties such as antioxidant activity and total polyphenol, acidity and pH, syneresis, texture (hardness, adhesiveness, springiness and chewiness), probiotics survival as well as sensory properties (taste, odor, texture, color and general acceptance) of yogurt samples in days 1, 7, 14 and 21 were measured. According to the results of the sensory evaluation team, the highest level of sensorial favorability was related to the control treatment. The lowest pH value in the control sample was 1% and showed a significant difference with the 2%, 3% and 4% treatments. The results of the survival of L. casei on different days showed that the effect of time and propolis percentage on the survival of probiotic was significant. The highest count of L. casei was observed in 4% treatment. It can be concluded that propolis can be used as a prebiotic in yogurt, which can improve the functional and textural properties of yogurt. [ABSTRACT FROM AUTHOR]