Studies on the Color Stability of Apple-roxburgh Rose Cloudy Juice During Storage

120 day storage experiment at 4 degrees C, 25 degrees C and 35 degrees C of apple-roxburgh rose cloudy juice was conduct-ted. The content of polyphenols, ascorbic acid, and the colour were assessed by analysis techniques. During the storage period of juice, the L* value decreased and the a*value increased with prolonge -d storage time and increased temperature. The colour change of the juice was acute during the initial 15 day storage period and then remained constant. The degree of color changing as well as the loss of tannin and ascorbic acid in the juice increased as the storage time prolonged and temperatures increased. The colour change (Delta E) of juice during the storage was caused mainly by the oxidation and polymerization of polyphenols but not by the degradation of ascorbic acid (R(2) for Delta E and total phenolic compounds loss was 0.711, and for Delta E and TVC loss was 0.007 respectively) and could be avoided by storing juice at a lower temperature. The addition of roxburgh rose to apple juice could inhibit the oxidation and polymerization of phenolic compounds