The effect of date liquid sugar and stevia extract as a sugar substitute on the quality characteristics of apple-lemon juice

Fruit juice is an important part of the diet in many human societies, and due to the consumption of sugar in the formulation, sugar substitution seems necessary to maintain health. In the present study, to replace sugar in apple-lemon carbonated fruit juice from two variables of stevia extract at three levels (0.002, 0.0035 and 0.005 g/l) and date liquid sugar at three levels (60, 80 and 100 g/l) were used. The effect of stevia extract and date liquid sugar on chemical properties (pH, acidity, total sugar, brix, carbon dioxide, dry residue, density), sensory and microbial were evaluated. The results showed that the linear (P<0.0001) and quadratic (P<0.05) effects of the predicted model of stevia extract on pH and acidity and for date liquid sugar on carbon dioxide, acidity and density were significant. Also, the interaction of two independent variables, respectively, showed that for stevia extract, the amounts of carbon dioxide, brix, dry residue, acidity and total sugar and for date liquid sugar, the amount of carbon dioxide, brix, dry residue and acidity, achieve an increasing trend first and then a decreasing one. The linear and quadratic effects of stevia extract and date liquid sugar on sensory properties of taste, oral fairy, texture and color were analyzed which were significantly different from the control sample and only exception was the quadratic power of stevia extract in the feature of oral fairy, which was not significant (P>0.05). Finally, the optimal values of 0.005 g/l of stevia extract and 93.570 g/l of date liquid sugar were obtained to achieve the desired physicochemical and sensory results for use in fruit juice formulation.