Prediction of postharvest Royal Gala apple softening

Rapid softening of Royal Gala apples during storage and market distribution is a serious commercial problem that can result in failure of fruit to meet stringent quality requirements demanded by markets. Prediction of softening rates before storage would allow industry personnel to segregate and market fruit appropriately for fruit lines with different storage potential. To develop a robust softening model it is important that pre and postharvest effects on softening are understood. Softening was triphasic, with an initial slow softening phase, a rapid softening phase, and a final slow softening phase. Maturity only influenced firmness at harvest, where fruit harvested later had lower harvest firmness. Once at 0 degreesC softening rates were similar regardless of harvest date. Softening rate increased with temperature from 0 degreesC through 22 degreesC, then decreased through 35 degreesC. Most of the reduction in softening rate from 22 to 0 degreesC occurred by 5 degreesC. Linear combinations of fruit characteristics at harvest related to subsequent softening rates for fruit from different orchards. These results in combination with future studies on other factors that influence softening should allow development of a model to predict softening rates through the postharvest handling chain.