Improvement of Fruit Firmness and Acidity in Controlled-atmosphere-stored ‘Golden Delicious’ Apples by a Rapid O2 Reduction Procedure1

Abstract ‘Golden Delicious’ apples ( Malus domestiea Borkh.) were subjected to regular air storage, to conventional controlled-atmosphere (CA) storage (O 2 reduced to 2.5% within 20–25 days of harvest by fruit respiration), or to several rapid CA procedures in which O 2 levels were quickly reduced to 2.5% by N 2 flushing. Fruit subjected to rapid CA (rapid reduction of O 2 ) was consistently 1 to 2 kg firmer and substantially higher in titratable acids than those in conventional CA or air storage at the conclusion of a 6- to 8-month storage period. Long delays in air at 0°C or at ambient temperatures before initiation of O 2 reduction resulted in softer fruit.