Relationship of harvest maturity to flavor regeneration after CA storage of ‘Delicious’ apples

Abstract

Red Delicious producers in the USA face increased pressure to produce fruit with optimum ‘on-shelf’ dessert quality following storage. In addition to firmness and soluble solids measurement other ripening-related events affect flavor perception. Ester production is always closely linked to the onset of climacteric ripening, while prolonged low-oxygen storage is usually detrimental to volatile production. Experiments focused on timing of the optimum harvest for maintaining sweetness, sourness and aroma generating capacity during CA storage. In multiple-harvest experiments with ‘Redchief Delicious’ apples, we investigated the relationship between the internal ethylene maturity indicator and flavor retention and regeneration after storage for different lengths of time. Using a cohort of untrained panelists, it was found that overall flavor perception and perceived fruit ripeness begins to increase at the onset of the climacteric. CA conditions reduce post-storage volatile production when compared with those stored in refrigerated air although not to a level below those displayed in ‘over-mature’ fruit at harvest after 3 months in storage. As harvest maturity advanced, the time required to regenerate aroma volatiles to an ‘optimum’ level after removal from CA storage decreased markedly. A linear relationship between attainment of optimal eating quality and time out of storage was established. Firmness, soluble solids, and titratable acidity of fruit from all harvest dates remained at acceptable levels throughout the post-storage ripening period.