The functional components of the antioxidant activity of plums
2005
Kojima, M.(Obihiro Univ. of Agriculture and Veterinary Medicine, Hokkaido (Japan)) | Miyashita, J. | Maeda, R. | Inagawa Y. | Muramatsu, Y.
Plums of 8 varieties (Early Rivers, Sun Prune, Robe de Sargenant, Chairn, Opal, Sunctus, Purple Ais, President) cultivated in Hokkaido in 2002-2004 underwent polyphenol extraction using 5% formic acid methanol, and amounts of polyphenol yielded and antioxidative activity were compared. Significant differences were observed between crops of different years. The Chairn and Sunctus varieties had the highest polyphenol content. These varieties also showed the highest combined antioxidative activity. Although there was a low correlation coefficient between the quantity of polyphenol monomers yielded and antioxidative activity, there was a high correlation between the amount of polyphenol polymers and antioxidative activity. Quantities of polyphenol polymers were calculated by subtracting the quantity of polyphenol detected by the HPLC method from the total amount of polyphenol as calculated by the Folin-Denis method. These results indicate that the main constituents responsible for antioxidative activity in plums are polyphenol polymers. In addition, the polyphenol content of plums cultivated under open-field and closed-field conditions (the latter excludes rain) were examined over 3 years. The results revealed that there was little change in the polyphenol content of closed-field-cultivated fruit throughout the year.
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