Evolution of bentonite and gelatin effects on clarification of variety of date fruit Kaluteh juice with response surface methodology

Date is one of important products that play important role in economy and nutritional health in some tropical regions of the world. Liquid sugar of date is produced by date syrup after extraction of phases, purification, and elimination of pectin compounds, protein, fiber, and color. This liquid has some characterizes such as 73% sugar with Brix 68-74% and it consists of mainly by glucose and fructose with similar ratio to honey hive and corn syrup with high fructose (HFCS) and It's color varies from brown to bright yellow. In this study, bleaching and clarification of keloteh variety date syrup to produce liquid sugar were investigated by response surface methodology (RSM) and face central composite design (FCCD). Three main factors including temperature (30-70\ub0C), pH (4-6), and time (40-120 minute) to determine the optimal condition of maximum activity of these two components (bentonite and gelatin) by constant adding were investigated. Also there are some factors such as color, ash, and absorption was determined. The optimal value of added bentonite and gelatin is determined 1-3 g/L and 0.02-0.08 g/L, respectively, which the desired amount is 3 and 0.05g/L, respectively. In low temperature and pH, the increased action of bentonite and gelatin is observed during passing the time and also high amount of impurities were removed. The lowest amount of these responses for color at 420 nm is (4302 ICUMSA), ash (0.421%) and absorption at 660 nm is 0.059. It is revealed that this technique can diminish the values of syrup color (68.25%), ash (8.7%), and absorption up to 89.46%, by comparing the values in the optimal point of clarified syrup by bentonite and gelatin with traditional method