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Darkening, Damage and Oxidative Protection are Stimulated in Tissues Closer to the Yam Cut, Attenuated or not by the Environment.

Research paper by Luiz Ferreira LF Coelho Júnior, Sérgio L SL Ferreira-Silva, Marcos Ribeiro MR da Silva Vieira, Marcelo M Carnelossi, Adriano Nascimento AN Simoes

Indexed on: 10 Jun '18Published on: 10 Jun '18Published in: Journal of the Science of Food and Agriculture



Abstract

This study investigated how the activities of the enzymes and metabolites of oxidative metabolism are affected in different regions of the cut tissue, associating these changes with the evolution of browning in fresh-cut yam. Samples were collected from yam at 0-5 mm and 5-10 mm from the cut site. Fresh-cut yams were stored at 5 and 26 °C, for days or hours, respectively, simulating the commercialization, with or without package. The results demonstrated that the injury to the yam was a physical inducer of changes in the levels of lipid peroxidation and phenolic compounds, and in the activities of Superoxide Dismutase, Catalase, Ascorbate Peroxidase, Polyphenoloxidase, and Peroxidase. These responses were significant in the tissue closest to the wound but also observed, although less intense, in the more distant tissue. The combined effects of wounding and dehydration during storage intensified the above responses. Conversely, refrigeration attenuated the transmission of the wounding response through the adjacent tissue. The results of this work provide the first evidence in cut yam roots that the membrane degradation products, enzymes involved in oxidative protection, and enzymes that modulate the oxidation of phenolic compounds are intertwined mechanisms that cause tissue darkening. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.