Enzymic Basis of Sharp Tissue Hardening in Post-Harvest White Trifoliate (D. dumetorum var.) Yam Tubers
[1]
Bernard T. N. Otubuah, Nutrition and Food Science Department, University of Ghana, Legon, Ghana.
[2]
George S. Ayernor, Nutrition and Food Science Department, University of Ghana, Legon, Ghana.
[3]
Firibu K. Saalia, Nutrition and Food Science Department, University of Ghana, Legon, Ghana.
Tissue hardenings in post-harvest vegetables are mediated by enzymes’ activities. In this study, activity profiles of peroxidase (EC 1.11.1.7), polyphenol oxidase (EC 1.10.3.1) and catalase (EC 1.11.1.6) in harvested and stored white trifoliate (D. dumetorum) yam tubers at room temperature (28±2˚C) and 72-85%RH and at refrigeration (5±1˚C) and 85-100%RH were studied and related to the development of hardness of the yam tissues. The results showed that tissue hardening in white trifoliate yam tubers stored at room temperature (28±2˚C) and 72-85%RH was increased with the storage period. Secondly, the high enzyme profiles in the white trifoliate yam tubers stored at room temperature (28±2˚C) and 72-85%RH were highly in phase with the sharp changes in tissue hardness. Also, a decrease in enzyme activities in white trifoliate yam tubers at refrigeration (5±1˚C) and 85-100%RH was comparable to no changes in tissue hardness, implying that very low enzyme profiles corresponds to no increase in tissue hardness.
Tissue Hardening, Peroxidase, Polyphenol Oxidase, Catalase, Post-Harvest, Enzymic Activities
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