Interaction of SmartFresh (1-MCP) and ReTain (AVG) on pears

The use of SmartFresh™ (1-MCP) technology to improve the quality of 'Bartlett' and 'Bosc' pears during storage was investigated. As well, the interaction of ReTain with SmartFresh on storage quality of 'Bartlett' pears was evaluated. Fruit were harvested from a commercial grower in 2005. After harvest, pears were held at 0°C for 3 days and then treated with or without 1-MCP (300 ppb) for 24 hours at 0°C. Following 1-MCP treatment, fruit were held at 0°C for 0, 2.5, or 4.5 months. After each cold storage period, 25 pears from each treatment combination were "preconditioned" at 10°C for 0, 5, or 10 days. Firmness, color, rots, disorders, and ethylene, respiration and volatiles were then followed at 22°C.

'Bartlett' Pears

• 1-MCP significantly delayed or prevented CO₂, ethylene, and hydrophobic volatile production in 'Bartlett' pears.

• ReTain had no significant effect on CO₂ or ethylene production in 'Bartlett' pears, but those treated with ReTain had less hydrophobic volatile production than pears without ReTain.

• 'Bartlett' pears treated with 1-MCP and/or ReTain and held in storage at 0°C were firmer and changed color (green to yellow) more slowly than control fruit. In some cases, the effects of 1-MCP and ReTain appeared additive.

• 1-MCP had little effect on soluble solids, whereas ReTain-treated pears tended to have higher soluble solids content.

• "Preconditioning" at 10°C had no significant main effects on quality of 'Bartlett' pears.

• After 4.5 months of storage at 0°C, most pears not treated with 1-MCP had deteriorated with severe senescent scald and/or storage rot, whereas pears treated with 1-MCP were still of acceptable quality.

• After 4.5 months at 0°C, 'Bartlett' pears treated with 1-MCP and ReTain, and no preconditioning at 10°C were the firmest after 5 and 10 days at 22°C. Pears with no ReTain that were preconditioned for 5 days at 10°C had the highest incidence of senescent scald and internal breakdown.

'Bosc' Pears

• 1-MCP significantly delayed CO₂ ethylene, and hydrophobic volatile production in 'Bosc' pears, but after 4.5 months of cold storage at 0°C the effect of 1-MCP on ethylene and hydrophobic volatiles was reduced.

• 'Bosc' pears treated with 1-MCP were firmer than non-treated fruit, but this effect was reduced with increased storage time.

• Pears treated with 1-MCP also changed color (green to yellow) more slowly than non-treated fruit.

• There was no significant effect of 1-MCP on soluble solids content.

• "Preconditioning" at 10°C had no significant effect on quality of 'Bosc' pears.

For more details or a copy of the project report, please contact Jennifer DeEll.

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