Improvement of internal color of oranges stored in oxygen-enriched atmospheres

‘Hamlin’, ‘Parson Brown’ and ‘Pineapple’ oranges were stored for 4 weeks at 15°C in a continuous flow of (1) air, (2) 20 mg 1^?1 ethylene (C₂H₄) in air, (3) 40% O₂ + 60% N₂, or (4) 80% O₂ + 20% N₂, followed by 2 additional weeks in air. Fruits stored in the C₂H₄ atmosphere lost rind chlorophyll faster, and the rind turned orange quicker, than fruits in the other atmospheres. However, most of the fruits stored in the C₂H₄ atmosphere had paler endocarp and juice than fruits stored in the other atmospheres. Fruits stored in 80% O₂ had the palest rind, but their endocarp and juice color were the deepest orange. Color change was detectable after 2–3 weeks and continued to develop until the end of the experiments. In 40% O₂ fruit, response was intermediate.The respiration rate of ‘Pineapple’ oranges during 4 weeks of storage in the test atmospheres was highest in the fruits stored in C₂H₄, almost as high in fruits stored in 80% O₂, and lowest in fruits kept in 40% O₂ or in air. Fruits stored in the different atmospheres did not differ significantly in total soluble solids content, total acidity, or pH of the juice, and the atmospheres did not adversely affect the flavor of the juice.