Effects of temperature, PH, sucrose andglycine on nonenzymatic browing in paprika paste and boiled grapejuice

ABSTRACT EFFECTS OF TEMPERATURE, PH, SUCROSE AND GLİCTNE ON NONENZYMATIC BROWNING IN PAPRIKA PASTE AND BOILED GRAPE JUICE BALIK, Z. Arzu M.Sc. in Food Engineering Supervisor: Assoc. Prof. Dr. Sami EREN February 1995, 73 pages The nonenzymatic browning reactions of paprika paste and boiled grape juice were studied. The effects of temperatures (5°, 25° and 35°), pH (3.0, 3.5 and 4.0 in paprika paste, 3.5, 4.0 and 4.5 in boiled grape juice), sucrose and glycine on these reactions were determined. Absorbance values were obtained at 420 nro and the graphs of absorbance versus time were drawn for paprika paste and boiled grape juice. It was found that, in both paprika paste and boiled grape juice, the highest browning was observed at 35°C, at pH 4.0 for paprika paste and at pH 4.5 for boiled grape juice. Addition of sucrose increased the browning reaction but addition of glycine was more effective than that of addition of sucrose. The highest absorbance values were obtained by the addition of both sucrose and glycine to both paprika paste and boiled grape juice. Activation energies were estimated to be in the range of 1.12-3.27 kcal/mole for paprika paste and 1.93-4.58 kcal/mole for boiled grape juice. Key words: Nonenzymatic Browning Reaction, Sucrose, Glycine, Maillard Reaction, Paprika Paste, Boiled Grape Juice.