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Doutoramento em Engenharia Agronómica - Instituto Superior de Agronomia Long-term storage of pears is a challenge in the absence of treatment with diphenylamine, due to the development of physiological disorders. Aspects of the ripening physiology and biochemistry of pears, particularly those treated with the ethylene action inhibitor 1-methylcyclopropene, also remain unknown. The aims of this thesis were to map the gradients of adenylate nucleotides and energy charge in the fruit and their changes during fruit ripening and storage period, to compare instrumental and sensory assessments of ripening, to relate the fruit mineral composition to the development of internal storage disorders and determine the optimal storage conditions for long-term storage of ‘Rocha’ pear under controlled atmosphere. Significant radial gradient in energy charge from the skin tissues to the fruit center may be related to internal storage disorders. Significant radial gradients in Ca and B decreasing from the skin tissues toward the fruit center were also consistent with the location of internal storage disorders. However, ‘Rocha’ pear were able to adjust the energy charge during ripening and long-term storage even under low respiration rates induced by 1- methylcyclopropene treatment or low oxygen partial pressure. ‘Rocha’ pear was able to ripen immediately after harvest without chilling or exogenous ethylene application. ‘Rocha’ pear tolerated extremely low 0.5 kPa O2 during 257 d storage without developing storage disorders and kept acceptable firmness and skin color after 7 d shelf life. The 46 d delay in the pull down of O2 partial pressure was detrimental to quality maintenance of ‘Rocha’ pear during long-term controlled atmosphere storage N/A |
