The enzyme preparation from seeds of sweet pepper (Capsicum annuum L.) showed a strong activity for (-)-epicatechin (EC) at about pH 7 and was inactivated at pH below 2. As the enzymatic oxidation of EC proceeded, absorbance from 235nm to 500nm increased, and a peak appeared at 380nm in the difference spectra. The peak height (_??_
E380) reached a maximum after 5 to 10 min and did not vary for about 60 min at 30°C. The _??_
E380 was directly proportional to the increased concentration of EC up to 90 μg/ml. Several sample solutions were analyzed by this method and by the vanillin-sulfuric acid colorimetric method. Highly accurate results were obtained by the present method, and the recovery was quite high.
View full abstract