Polyphenol Contents and Enzymatic Browning of Plums Harvested in Japan

Food Chemical Studies on Plum Fruits (Part IV)

Abstract

Polyphenol compounds in six plum varieties were studied to elucidate the relationship between the contents and enzymatic browning of the plums by crushing. The total contents of polyphenols were 167 (Santa Rosa) to 250 (Sordum) mg%. The ratio of flavanol tannin and chlorogenic acid to the total polyphenol was almost same, 86 to 99% of the polyphenols were consisted with these compounds. The degrees of the enzymatic browning of the plums by crushing were as follows; Methley>Sordum>Ooishi Wase>Beauty>White Plum>Santa Rosa, on the other hand, the color of the juice of "Santa Rosa" did not change. Optimum pH and temperature of the enzymatic browning were pH 4.5 to 5.0 and 35°C. The polyphenol extracted from "Methley" plum was not oxidized for 50 days at 30°C by the addition of potassium metabisulfite.