Retardation of ‘Hayward’ kiwifruit tissue zone softening during storage by 1-methylcyclopropene

Abstract

The use of the ethylene action inhibitor 1-methylcyclopropene (1-MCP) is becoming more common in the global kiwifruit industry as a tool for firmness management after harvest. The overall fruit firmness measured by penetrometer or compression is dependent on the relative changes in texture of the three main tissue zones: the outer pericarp, inner pericarp and core. This research has investigated the way in which 1-MCP affects the firmness of individual tissue zones during storage, and the changing response of 1-MCP treated fruit to ethylene. 1-MCP retarded fruit softening as measured by whole fruit compression or penetrometer. However, there was a long period in storage where the compression test did not show the same degree of softening as was detected by the penetrometer measurement. In addition, it was shown that 1-MCP retarded the softening of the three tissue zones investigated. The exposure of 1-MCP treated fruit to ethylene at intervals throughout storage demonstrated the long term nature of the anti-ethylene effect of a 1-MCP treatment at the start of storage; an effect that persisted in all three tissue zones. It is concluded that 1-MCP retards the overall softening of ‘Hayward’ kiwifruit, whether measured by compression or penetrometer. More specifically, the treatment affects the softening of the outer pericarp, inner pericarp and core tissues to a similar extent. The protective effect of a 1-MCP treatment at the start of storage against exogenous ethylene persists to some degree throughout storage.