65A-21

Tomatoes used for fresh market sales currently have a limited shelf life. Methods to prolong their shelf life would have both military and civilian benefits.

 

Objectives of this study were to evaluate growth hormones and post-harvest handling techniques on fresh market and processing tomato varieties.  Fruit were treated with various growth hormones and then held in either paper or modified atmosphere bags under a range of temperatures.  The growth hormones used were gibberellic acid 4,7 (GA_4,7), benzyladenine (BA), aminoethyoxyvinylglycine (AVG) and 1-methylcyclopropene (MCP). Fruit were dipped in GA_4,7, BA or AVG solutions or exposed to MCP gas.  Tomatoes were evaluated for color, defects, firmness, edibility index and total plate counts.  Bag oxygen, carbon dioxide and ethylene levels were also monitored.

 

The results show that MCP, temperature, variety and bag type had the most effect.  Lower temperatures caused chilling damage. Room temperature storage worked better in all conditions but the fruit dried out after prolonged storage in paper bags. The paper bag did not slow ripening.  Fruit shelf life was extended when held in modified atmosphere bags but moisture built-up with the fresh market varieties leading to increased spoilage.  Once a tomato spoiled, other tomatoes in the same bag also spoiled quickly.  Processing tomato varieties performed better than fresh market types.  The only growth hormone benefiting shelf life was MCP.  An initial exposure of 200 ppb for 8 hr. at 20^oC resulted in a doubling of tomato shelf life when using the fresh market varieties. 

 

These results suggest that the most important parameters to prolonging tomato shelf life are variety, storage temperature, MCP and modified atmosphere.  Tomato shelf life from 6-8 weeks is now possible by properly implementing these parameters.