Re-evaluation of harvest timing in ‘Unique’ feijoa using 1-MCP and exogenous ethylene treatments

•Fruit harvested 2 weeks before commercial harvest retained quality for 6 weeks.•Harvest maturity influences post storage outcomes more than ethylene manipulation.•1-MCP treatment of early harvested feijoa influences firmness and internal colour.•Feijoa are insensitive to exogenous ethylene irrespective of harvest time.

In New Zealand feijoa are harvested by touch-picking and can be stored in 4 °C for up to 4 weeks with a subsequent shelf life of 5–7 d at 20 °C. The origins of the ‘touch picked’ harvest maturity standard may have been established to provide “ready to eat” fruit rather than those suitable for storage. Despite the climacteric physiology of the fruit, previous studies which apply either 1-methylcyclopropene (1-MCP), ethylene or propylene on postharvest touch-picked ‘Unique’ feijoa have been found to have no impact on storage life. Harvesting fruit earlier may have advantages in that fruit may possess more storage life and/or may be more responsive to 1-MCP treatments. The aim of this study is to establish the role of harvest timing on postharvest performance of feijoa and investigate whether 1-MCP or exogenous ethylene applied to earlier harvested fruit modifies ripening and deterioration under storage conditions. The experiment had a full matrix of three harvest times (approximately at two week intervals, with the last maturity being the current commercial standard of touch picked) and three treatments: 1-MCP treatment prior to storage, ethylene treatment during storage and air as a control. Fruit (cv. Unique) were stored at 4 °C and 90% RH for 6 weeks with physiology (respiration rate and ethylene production) and quality assessed at two week intervals both after removal and a subsequent 5 d at 20 °C. Harvest timing significantly influenced fruit maturity. Postharvest 1-MCP application delayed ripening of early harvested fruit while having no impact on touch picked fruit. Respiration rate, softening, loss of flesh colour (°hue) and locule development of fruit were suppressed by 1-MCP, but had no effect on weight loss, soluble solids content (SSC), titratable acidity (TA) and skin colour. Fruit were insensitive to exogenous ethylene treatment suggesting that natural endogenous ethylene may be saturating receptors. Fruit harvested 2 weeks prior to touch picked maturity ripened and appeared visually acceptable after 6 weeks of storage. However, these fruit were low in SSC with high TA suggesting that taste may be altered. There may be potential to provide extended storage life for feijoa through early harvesting although consumer acceptance trials of the likely new taste profiles are required.