CHANGES IN VOLATILES DURING COLD STORAGE AND SUBSEQUENT SHELF-LIFE OF 'CONFERENCE' PEARS TREATED WITH 1-MCP

Abstract

European pears (Pyrus communis L. ‘Conference’) were untreated or treated with 5 µl/L 1-methylcyclopropene (1-MCP) for 24 h at 20°C and then kept at 1°C for 80 days. The 1-MCP concentration was achieved by adding 1 g Smartfresh (Agrofresh Inc.) containing 0.14% 1-MCP as active ingredient into the 180-L free space. Pears were evaluated after 20, 30, 40, 50, 60, 70 and 80 days of storage at 1°C followed by shelf life storage at 20°C and normal oxygen atmosphere for 7 days. Evaluative criteria were firmness, soluble solids concentration (SSC), respiration rate, production of ethylene and production of volatile compounds. 1-MCP treated pears kept at 20°C (shelf life) had statistically significant slower softening than untreated fruits (P≤0.01). Treated fruits were 0.40 MPa firmer than control fruits after a 7-day shelf life period. The effect of cold and 1-MCP treatment resulted in significant inhibition of ethylene production, respiration rate and retention of flesh firmness after transfer to room temperature. A significant (P≤0.01) increase in ethylene production was observed in untreated fruits during the whole storage period. In terms of determining the effect of 1-MCP on the quality of pears, it is also important to examine the production of volatile aromatic compounds. 104 volatile compounds were sampled by head space SPME and identified by GC-MS, from which ethyl acetate, 2-methyl-1-butyl acetate, ethyl benzoate, and citronellol were significant.