Effects of Influence Parameters on Color Formation in Glucose Syrups during Storage

Effects of pH, temperature, and syrup concentration on color formation in glucose syrups were studied and the shelf life of syrups under various conditions was estimated. Temperatures of 5, 25, and 45 ºC, pH values of 4, 5, and 6 as well as concentrations of 30, 40, 50, 60, 70, and 80 ºBrix were examined. After 26 weeks no significant color changes were observed at 5 ºC. At 45 ºC, color formation rate was highest and after 2 weeks color changes were visible, and at 15th week syrup color was completely brown. At 25 ºC, color formation rate was low and at week 18 color changes were visible. At pH 5, rate of browning was lower than at other pH values. Increasing the syrup concentration up to 70 ºBrix enhanced the color formation rate but higher concentrations decreased the color formation rate. The kinetics of color formation was studied and rate constants and activation energies were calculated.