PHENOLICS OF GREEN PEPPER BERRIES (PIPER-NIGRUM L)

The nature of phenolic compounds and their involvement in enzymatic blackening of green pepper berries during conventional sun-drying were investigated. Among the five commercial varieties of pepper studied, a great variation in the total phenolics including o-diphenol oxidase oxidizable phenolics was noted. However, no correlation was observed between the total or o-diphenol oxidase oxidizable phenolic content of a particular variety and the extent of its blackening. Conversion of green pepper to black pepper by the drying process was accompanied by a 75% decrease in total phenolic content and a complete loss of o-diphenol oxidase oxidizable phenolic fraction that suggested a major role for the enzymatic phenolic oxidation during the pepper blackening. A compound that served as an efficient substrate for pepper o-diphenol oxidase was isolated for the first time from green pepper berries and was characterized as 3,4-dihydroxy-6-(N-ethylamino)benzamide on the basis of chromatographic and spectrometric methods. © 1990, American Chemical Society. All rights reserved.