SHELF LIFE EXTENSION OF APPLES WITH POLYMERIC FILMS

Loss of green colour in Granny Smith apples after 8 weeks storage was strongly temperature dependent with almost complete yellowing occurring at 15°C and 20°C and none at 0°C. Overwrapping fruit with PVC film created modified atmospheres (MA) and prevented yellowing at all temperatures. For fruit stored in a range of atmospheres at 20°C yellowing was correlated with oxygen concentrations over the range 4 to 20% O₂. Using Braeburn apples the beneficial effects of MA packaging on green colour retention were maintained when CO₂ and C₂H₄ were scrubbed from pack atmospheres. These results clearly indicated that it was the reduced O₂ levels developed within the package which were responsible for the inhibition of yellowing achieved with MA packaging.