2530
M. MURATA et al.
Biochem., 65, 383–388 (2001).
tion between CQA-Q and catechins will be further
examined. Richard-Forget et al. have pointed out the
involvement of the peroxidase in the enzymatic
browning of pear.23) Pear peroxidase did not react
with phenolics, but in the presence of polyphenol oxi-
dase, peroxidase enhanced the phenol degradation.
Considering our results, H2O2, the substrate of
peroxidase, seems to have been generated through
CQA-Q formed in the reaction mixture of pear PPO
and phenolics.
We conclude from these results that CQA-Q itself
and the mixture of CQA-Q and amino acids did not
form the intense brown pigment in the acidic aqueous
solution. H2O2 spontaneously generated from CQA-
Q and polyphenols other than CQA might have
played an important role in forming the intense
brown pigments by enzymatic browning.
11) Cilliers, J. J. L., and Singleton, V. L., Characteriza-
tion of the products of nonenzymic autooxidative
phenolic reactions in a caŠeic acid model system. J.
Agric. Food Chem., 39, 1289–1303 (1991).
12) Fulcrand, H., Cheminat, A., Brouillard, R., and
Cheynier, V., Characterization of compounds ob-
tained by chemical oxidation of caŠeic acid in acidic
conditions. Phytochemistry, 35, 499–505 (1994).
13) Puä tter, J., and Becker, R., Peroxidase. In ``Method
of Enzymatic Analysis, Third Edition, Vol. 3'', ed.
Bergmeyer, H. U., Verlag Chemie, Weihenheim, pp.
286–292 (1983).
14) Richard, F. C., Goupy, P. M., Nicolas, J. J.,
Lacombe, J.-M., and Pavia, A. A., Cysteine as an
inhibitor of enzymatic browning. 1. Isolation and
characterization of addition compounds formed dur-
ing oxidation phenolics by apple polyphenol oxidase.
J. Agric. Food Chem., 39, 841–847 (1991).
15) Yabuta, G., Koizumi, Y., Namiki, K., Hayashi, T.,
and Namiki, M., Novel benzacridine derivative in the
green pigment from methyl caŠeate and butylamine.
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16) Yabuta, G., Koizumi, Y., Namiki, K., Hida, M., and
Namiki, M., Structure of green pigment formed by
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with a primary amino compound. Biosci. Biotechnol.
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17) Sanoner, P., Guyot, S., Marnet, N., and Drilleau,
J.-F., Polyphenol oxidation in cider apple model: ki-
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