Stone Fruit Ripening Advantages
Reduces fruit’s susceptibility to bruising during transfer
Generally speaking, stone fruits are least susceptible to bruising at transfer point pressure. In the transfer range, the cell walls of the fruit are most flexible, like rubber balls. At higher pressures, the cells are hard and breakable, and at very low pressures the cell walls are ready to burst with juice. Target the transfer pressure in ripening, and when reached, move the fruit quickly to sale or use.
Adds flexibility in product storage and flow
Once stone fruit has reached transfer point pressure, it is perfectly safe to move ripe stone fruits back into a cold storage area. The change in temperature will temporarily stop the ripening process and will not harm the fruit. Once stone fruits have arrived at transfer point pressure, internal breakdown is halted, so there is no longer any danger in the “killing range.” Fruit can be transported and held at store or final destination levels at cold storage temperatures.
Stone Fruit Ripening Cautions
Slow-Ripening Plums
For some very slow-ripening plum varieties, ethylene exposure is required to induce and accelerate the ripening process. These varieties include Black Beaut, Kelsey, Casselman, and Angeleno. If they are not given special attention, these varieties vary in performance, depending on chance exposure to ethylene during handling. During ripening, these varieties should be continuously exposed to ethylene at warmer temperatures to ripen properly. This exposure can be accomplished by placing these plums near other ripening fruits that produce ethylene, such as other stone fruits, pears or bananas.
Early Varieties
Varieties harvested in the month of May grow rapidly to be ready for market early. They also soften rapidly and may be prone to soft tips. Early varieties should be checked at least twice daily and moved through the system promptly. May varieties are also more flexible in terms of holding temperature – they are not susceptible to internal breakdown and will not be damaged in the “killing range” of temperature.
Summerwhite Peaches and Nectarines
Applying the ripening protocol to Summerwhite® white peaches and nectarines is not recommended for several reasons. These varieties soften more quickly than yellow varieties and bruise easily. Most Summerwhite® varieties are “low acid” and they taste very sweet even when quite firm. Additionally, in general, white flesh peaches and nectarines are not susceptible to internal breakdown.
Bagged Stone Fruit
Bagged stone fruit is also not recommended for the ripening protocol. Due to the high-humidity environment created by the plastic bag, softening is accelerated and decay more likely. Maintain safe temperatures on this fruit and execute quick turns.