Preparation of Low Calorie Sour Tea Jelly Using Stevia and Gelatin of Chicken Skin- Evaluation of the Product

The aim of this study was to produce low-calorie jelly using sour tea as a natural coloring agent, gelatin extracted from chicken skin with stevia as sweetener. Chicken skin gelatin was extracted by using alkaline-acid pre-treatment with 1 N of NaOH and 0.05 N hydrochloric acid. Gelatin was used at the concentrations of one and two percent (wt.%), Stevia with 0 to 100% replacement rates with sugar and sour tea at 20 wt.% for 100 g of jelly and 48 hours after gel production, pH measurement, Brix, moisture content, acidity, water activity, tissue stiffness, color, sensory analysis and microbial tests were performed. Experiments were conducted in a completely randomized design based on factorial experiment using SPSS software and compared with Duncan's multiple range test at 5% probability level. The results showed that by increasing gelatin concentration and the level of sucrose replacement with stevia did not have a significant effect on pH. By increasing the concentration of gelatin, texture hardness and L*, significantly increased and moisture decreased (p < 0.05), whereas the parameters of brix, water activity, a* and b* of samples were not significantly different (p> 0.05). By increasing the levels of sucrose replacement with stevia and decrease of solids content the moisture, water activity and L *, a *, b * factors were significantly increased and the brix of the samples decreased. Sensory and physicochemical properties of sour jelly samples showed that using chicken skin gelatin and stevia as sweetener could be a good alternative to low-calorie jelly formulation by preserving physical, chemical and sensory properties. Due to medicinal properties, sour tea provides beneficial contribution to sour jelly product