Response of Three Strains of ‘Gala’ Apples to High Carbon Dioxide Prior to Controlled Atmosphere Storage

Abstract

The postharvest fruit quality of three strains ('Royal Gala’ ‘Imperial Gala’ and ‘Crimson Gala') of apples was evaluated over two or three storage seasons. To determine the influence of carbon dioxide treatment on storage quality, apples were stored in normal controlled atmosphere (1% O ₂& 1% CO ₂), or treated with 12% CO ₂for 7 or 14 days prior to normal CA and evaluated after 90 or 150 days of storage. The use of 12% CO ₂prior to storage helped to maintain firmness of ‘Royal Gala’ apples in 1 of 3 seasons. Firmness of ‘Imperial Gala’ and ‘Crimson Gala’ apples was not influenced by high CO ₂treatment, regardless of storage season. Other quality factors (color, soluble solids, acidity and carbohydrates) were not influenced to the extent that high CO ₂would be a viable option for the quality enhancement of ‘Gala’ apples during storage, regardless of strain. Use of normal CA maintained ‘Gala’ apple quality for 150 days of storage. Harvest date had a major influence on ‘Gala’ apple quality. A delay of one week reduced firmness and acidity, but enhanced color and content of sucrose, glucose and fructose in ‘Royal Gala,’ ‘Imperial Gala’ and ‘Crimson Gala’ apples.