Postharvest Cooling and Handling of Peppers
The preferred temperature range for peppers is from 45 to 50 °F. Since pepper harvesting in North Carolina normally occurs during the hottest months of the year, it is not unusual for the pulp temperature of harvested peppers to be more than 90°F. If they are allowed to remain at high temperatures for more than 1 or 2 hours, they will begin to show signs of shrinkage, softening, and eventually disease infestation. In addition, temperatures greater than 70°F greatly accelerate ripening and color changes.
Peppers are also sensitive to chill injury. Cooling them to temperatures below 40°F can result in softening, pitting, and predisposition to decay. Overcooling is just as serious a problem as undercooling.
Under optimum storage conditions--low temperature (40 to 45 °F) and high relative humidity (90 to 95 percent)--peppers may be stored for as long as three weeks with little loss of quality, although there is seldom any reason to hold them that long. Frequent inspection and the addition of a suitable fungicide to the wash water are necessary to prevent disease infestation. Controlled atmospheres low in oxygen and high in carbon dioxide have been shown to retard color change due to ripening and to help maintain quality during storage and transit.
Peppers are sensitive to the natural ripening hormone ethylene, a colorless and odorless gas produced as a natural by-product of ripening by some fruits and vegetables. The presence of even minute quantities can hasten ripening. The combination of high temperatures and ethylene can increase the ripening rate twentyfold or more. Thus, ethylene-producing crops such as apples, pears, and tomatoes should never be stored or shipped with peppers.