ABSTRACTBoth enzymatic betacyanine and betaxanthine decolorizing activity were found in subcellular tissue extracted from the beet root. The optimum pH for betaxanthine degradation was pH 3.4, similar to that for betacyanine. Enzyme preparations from different cultivars, i.e., red or yellow, vary in their activities toward betacyanine and betaxanthine. A major portion of the decolorizing activity was found in tissue separated from the epidermal portion of the beet root where most pigments were accumulated. Sodium chloride, cellulase, and pectinase were selected as agents to solubilize the tissue bound enzyme. Although there was little success in bringing the bound enzyme into a soluble form, it was found that NaCl showed inhibitory effect on the beet betacyanine decolorizing enzyme. Commercial enzyme preparations also contained betacyanine decolorizing activity.SUMMARYTHE CRUDE ENZYME extracts from the beet root showed decolorizing activity to both betaxanthines and betacyanines. The attempt to clarify whether these two reactions were initiated by the same enzyme or by different enzymes was not achieved due to the difficulty of solubilizing the tightly bound macromolecules. In addition to the decolorizing enzyme found in the beet root, a betacyanine decolorizing enzyme was also found in several commercial enzyme preparations. The mechanism of enzymatic degradation of the betalaines, the existence and the nature of the responsible enzymes and factors that affect their activity, are open for further study. Such understanding will be utilized to improve betalaine recovery from the beet root during industrial operations and to increase their stability in food products during processing or storage. Perhaps, the elucidation of enzymatic destruction of betalaines will provide information for determining the environmental or chemical degradation mechanism of the pigments themselves.
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