Effect of maturity and storage on quality and volatile production of 'Jonagold' apples

'Jonagold' apples (Malus domestica Borkh.) harvested 3 times at bi-weekly intervals starting approximately two weeks prior to commercial harvest were stored at 0 degrees C in air and controlled atmosphere (CA, 1.5% O-2 + 1.5% CO2 for six months. Starch index (SI) increased from 2.1 to 8.4 during the harvest period. Early harvests and CA significantly (P less than or equal to 0.05) reduced the loss of acidity and firmness in stored apples but did not influence total soluble solids content. CA decreased the volatile production testers, alcohols, and hydrocarbons) by half. The last harvest (SI = 8.4) provided an increase of 14% in volatiles compared to the first date (SI = 21). These increases were mostly due to straight C3-C6 chain acetates and alcohols, and the hydrocarbon alpha-farnesene. Variation in background skin colour within the same harvest period had a negligible effect on volatile patterns. Harvest at starch index values of 6.5-8.5 allowed higher concentration of odour-active compounds while retaining acceptable levels of acidity and firmness.