Modified atmosphere storage for reduction of bitter pit in some New Zealand apple cultivars

Abstract ‘Red Delicious’, ‘Golden Delicious’, ‘Braeburn’ and ‘Granny Smith’ apples stored in polyethylene bags (polybags) 25 (μm thick containing microperforations made with a 1 mm diam. cold needle, had less bitter pit after 7 weeks storage at 1°C and 7 days shelf-life simulation at ambient temperature than unbagged apples from the same storage environment. Carbon dioxide concentrations increased and oxygen decreased as the number of microperforations in polybags was decreased. Commercially acceptable levels of bitter pit (less than 5%) could be obtained with ‘Red Delicious’ apples when CO2 and O2 concentrations inside polybags exceeded 5% and fell to 15–16% respectively. ‘Red Delicious’ and ‘Golden Delicious’ apples stored in microperforated polybags lost less weight, were firmer and had better eating quality than fruit not stored in polybags. It is suggested that polybags containing 50–70 microperforations could be adopted commercially for the apple cultivars tested, to reduce bitter pit and maintain f...