Pome fruits

Abstract

Controlled atmosphere (CA) and modified atmosphere (MA) are most widely used for the commercial storage and transportation of apples and pears. After it was first described in the U.K. in the 1920s and actively researched in several countries in the 1930s and 1940s, the commercial use of CA storage for apples rapidly expanded in the 1950s and has subsequently been adopted worldwide. Since its initial commercialization in the 1950s, several improvements in CA technology have been made. These include rapid CA systems, which allow atmosphere set-points to be reached within 1 or 2 days; use of low oxygen concentrations (0.7-1.5 kPa) that can be accurately monitored and controlled; ethylene-free CA, programmed (or stepwise) CA, and dynamic CA where levels of O2 and CO2 are modified as needed, based on monitoring specific attributes of produce quality, such as ethanol concentration and chlorophyll fluorescence. MA packaging of pome fruits includes pallet covers, consumer bagging, and most commonly for packaging fresh-cut apples and pears. A generally used MA approach for intact pome fruits is the application of edible coatings (waxing) in the United States and many other countries. 1-Methylcyclopropene (1-MCP), an ethylene inhibitor, was approved by U.S. EPA in 2002 and produced by AgroFresh Inc. (Springhouse, PA) with the commercial trademark of SmartFreshSM. The use of 1-MCP in combination with CA can further improve storability of fruits and this has led to changes in CA storage management, particularly for apples.