|Bai, Jinhe - VISTING SCIENTIST|
|Mattheis, James - USDA/ARS TREE FRUIT LAB,|
|Brecht, Jeffrey - UNIV OF FL; HORT SCI DEPT|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 12, 2003
Publication Date: N/A
Technical Abstract: Apples ('Gala' , 'Delicious', 'Granny Smith', and 'Fuji') +/- pretreatment with 1-methylcyclopropene (1-MCP, 18 h at 0.625 - 1.0 µL L-1) were stored in controlled atmospheres (CA: 1-1.5 kPa O2 ; 1-2 kPa CO2 ) or in regular atmosphere (RA) for up to 8 months at 1°C. Firmness, titratable acidity (TA), soluble solids (SS), and volatiles analyzed via gas chromatograph (GC), and electronic nose ('Gala' only) were monitored every month directly or after transfer to air at 20°C for 1 week to simulate marketing conditions. CA and/or 1-MCP + RA treatments delayed ripening and prolonged storage life as indicated by decreasing loss of firmness and TA in all four varieties during storage. CA and/or 1-MCP + RA also slightly decreased the loss of SS for 'Gala' but had no effect on the other varieties. There were differences among treatments for firmness and levels of TA (1-MCP + RA > CA) for 'Gala', 'Delicious' and 'Granny Smith' apples (especially after transfer of fruit to 20°C), however, the reverse was found for 'Fuji'. A combination of 1-MCP + CA was best (1-MCP + CA > 1-MCP + RA or CA) for maintaining 'Delicious' firmness and acidity. CA and 1-MCP inhibited 'Gala' volatile production similarly at low temperature, but the effect of 1-MCP was greater at room temperature. Canonical discriminant analysis of electronic nose data separated the storage treatments (1-MCP+CA, 1-MCP+RA, CA, RA), indicating that the volatile profiles were different in fruit from each treatment (confirmed by GC analysis). The differences in volatile profiles by treatment increased with increasing storage time, and especially after transfer to 20°C. For inhibition of 'Gala' volatile production, 1-MCP + CA > 1-MCP + RA or CA. Therefore, 1-MCP + RA was the best treatment for storing 'Gala' apples with minimal loss of volatiles, while maintaining firmness and acidity. The results indicate that the efficacy of 1-MCP and CA in maintaining apple quality factors is variety dependent based on one season's data.