Rapid, uniform warming of cannery pears

Pears in a simulated bin were warmed for ripening from 30° to 68°F in 15 and 25 minutes with 110°F air forced through the bin with air flow rates of 2 and 1 cubic ft per minute per pound of fruit, respectively. Pears held for up to two hours in the warm, rapid air flow were not adversely affected. Pears ripened to processing firmness in three to four days when warmed to 68°F in four hours or less. Fruit delayed in warming from one to seven and one-half days was delayed in ripening in almost direct relation to the time required to reach 68°F. Slow warming resulted in uneven ripening with soft and hard fruit in the same him. The concept of a warming tunnel to attain uniform ripening and allow a processor to precisely program a canning schedule is suggested.