Internal appearance and chilling-injury symptoms of June Gold peaches harvested at different maturity stages — commercial harvest and tree-ripe — and preconditioned following four weeks of storage at 32 degrees Fahrenheit plus two days at shelf life (68 degrees). (Courtesy Ioannis Minas) — Internal appearance and chilling-injury symptoms of June Gold peaches harvested at different maturity stages — commercial harvest and tree-ripe — and preconditioned following four weeks of storage at 32 degrees Fahrenheit plus two days at shelf life (68 degrees). **(Courtesy Ioannis Minas)**

Even when a grower harvests perfect peaches, the consumer still may not be biting into a tasty fruit at home, and postharvest practices may be partially to blame, said peach researcher Ioannis Minas, assistant professor of pomology at Colorado State University, at the 2018 Great Lakes Fruit, Vegetable and Farm Market Expo in December. Fortunately, he added, there’s a fairly simple solution.

He and his group looked at a typical postharvest peach scenario, in which growers immediately put harvested peaches in chilled storage, where the fruits remain for two to four weeks.

For June Gold peaches coming out of cold storage, they found considerable flesh bleeding, which is a visual sign of internal breakdown, and mealiness. All fruits picked when fully ripened (tree-ripe) showed both mealiness and flesh bleeding. Commercially harvested fruits (those picked two days earlier) fared better, with 40 percent experiencing mealiness, and 25 percent showing flesh bleeding.

“The more mature and riper the fruit is, the more susceptible to storage disorders it becomes,” Minas said.

Then, the researchers tried something different. Instead of putting the commercially harvested peaches immediately into cold storage, they preconditioned the peaches by first holding them at 68 degrees Fahrenheit for two days. That completely eliminated mealiness and flesh bleeding, and also protected fruit quality.

This finding is especially important because chilling injuries aren’t obvious in fruit coming out of cold storage. Rather, Minas said, “they become visible later when a buyer consumes the fruit, and that’s a problem because it contributes to the trend of seeing less and less consumption of peaches.”

—by Leslie Mertz