The effect of green tea extract on the viability of Lactobacillus casei and the qualitative characteristics of a probiotic drink based on a mixture of celery, carrot and apple juice

In this research, the effects of different concentrations of green tea extract (0, 1.5, and 2.5 percent) on Lactobacillus casei survival, antioxidant activity, and drinking sensation of probiotics based on a mixture of different concentrations of celery juice (10, 15, and 20 percent), apple juice (5, 7.5 and 10%) and carrot juice (5, 7.5 and 10%) were investigated. 10 treatments were investigated with three replications. The qualitative characteristics of the probiotic drink samples were investigated during the storage period (first, eleventh and twenty-first days). Based on the obtained results, increasing the percentage of green tea as well as the concentration of celery, carrot and apple juice decreased the pH and antioxidant activity (DPPH radical inhibition percentage), phenolic compounds, as well as increased the viability of Lactobacillus casei and organoleptic properties in the probiotic drink (p<0.05). On the other hand, the duration of storage decreased the pH and antioxidant properties (p<0.05). Also, the survival of Lactobacillus casei decreased during the storage period (p<0.05). The treatment had the highest amount of green tea (2.5%) and the highest concentration of celery juice (20%), carrot (10%) and apple (10%) and the highest sensory quality (taste, smell, texture, color, overall acceptance) and The population of probiotic bacteria in this treatment was more than 7 log cfu/g on the 21st day.