Physicochemical and Nutritional Stability of Optimized Low-calorie Quince (Cydonia oblonga) Jam Containing Stevioside During Storage
It is now generally recognized that the high-calorie diets with inadequate physical activity result in many diseases such as obesity. In this work stevioside as an artificial sweetener and pectin as stabilizer were applied to prepare low-calorie quince jam. In order to manufacture product with desirable properties, different factors such as percentage of pectin, stevioside and sugar was evaluated and optimized by response surface methodology (RSM). For determination ofoptimum points, two responses, viscosity and Brix were used. In the second part of this study, the effect of temperature (4 and 25°C) on physicochemical and sensory properties of the jam was measured every 20 days over 60-day storage. The optimized formula of reduced-calorie quince jam was obtained by pectin, stevioside and sugar content of 0.4, 0.27 and 50%, respectively. Storage time had a significant effect to decrease monomeric anthocyanins, total phenolic compounds, vitamin C and Brix significantly, whereas jam water activity and pH increased. On the contrary, storage temperature did not show any significant influence on physicochemical properties of jam. Totally, the results showed that the production of low-calorie quince jam using stevioside can be industrially applicable and recommended to people who are interested in consumption of reduced-calorie foods.