Enzymic Treatment of Cocoa, Coffee and Tea with Polyphenol Oxidase

Abstract

The enzymic browing of extracts from cocoa, coffee and tea was examined using the polyphenol oxidase from Alternaria tenuis strain A-2 and applications of the enzyme were developed. Fermented cocoa was more easily oxidized than unfermented or roasted ones. All cocoa extracts became deeper brown as a result of the enzymic oxidation. Raw cocoa beans which corresponded to fermented cocoa beans were prepared by treating unfermented ones with the enzyme. Coffee extracts were also oxidized by the enzyme. Green coffee turned brown, and roasted one became deeper brown on account of the enzymic oxidation. Darker colored coffee beverage was prepared by the enzymic treatment of instant coffee. Green tea was readily oxidized by the enzyme and turned brown. Instant tea was prepared by converting green tea to black tea using the polyphenol oxidase.