摘要：

Dehydroascorbic acid (DHA) and 2,3-diketogulonic acid (DKG), formed from ascorbic acid (AA) during dehydration of cabbage, react nonenzymatically with the free amino acids to cause red to brown discoloration in the dried product. Using model systems, the mechanism of color formation has been shown to involve the Strecker degradation of amino acids to aldehydes. An alcoholic medium and AA instead of preformed DHA or DKG are more favorable for aldehyde formation at a low temperature (40° C.). The red color formed initially in freeze-dried cabbage and in model systems has a pH optimum in the range of 5.3 to 6.5 for development and behaves like the rearranged product of a Schiff base. The conversion of red color to brown is accompanied by the liberation of carbonyl groups. Blanching causes oxidation of AA and enhances the extent of browning in the hot air-dried product.

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