Published 2019-04-19
Abstract
Summer squash (Cucurbita pepo L.) is a high value fresh produce item, but its marketability is limited by sensitivity to low temperature, which varies among different types of summer squash. In particular, symptoms of chilling injury (CI) develop quickly and are highly visible in the yellow type of summer squash at temperatures below 12 °C and the product quickly becomes unappealing to consumers, rendering it unmarketable. Ethylene production has been associated with development of CI. The purpose of this research was to observe the effect of 1-methylcyclopronene (1-MCP; SmartFreshTM), which blocks ethylene action, on CI development in yellow summer squash fruit. ‘Colorado 601’ yellow summer squash that had been treated or not with 1-MCP were held at 1 °C or 10 °C for 1 or 2 weeks, then transferred to 20 °C for 2 days. Ethylene production was reduced by 1-MCP at both storage temperatures as well as after transfer to 20 °C. Chilling injury symptoms, including pitting, lenticel discoloration, and surface scald, increased in severity during storage at both temperatures, but more so at 1 °C, and CI symptoms were reduced by 1-MCP. Electrolyte leakage (EL) was increased by 1-MCP after 2 weeks at 1 °C, but EL was reduced by 1-MCP after both 1 and 2 weeks at 10 °C. Electrolyte leakage appears to be an indicator of senescence rather than CI in yellow summer squash. Treatment with 1-MCP extended the shelf life of yellow summer squash by limiting both CI and senescence and thereby maintaining postharvest quality factors.