45G-17 |
Prophylactic protection of iceberg lettuce heads with postharvest MCP applicaton |
R. M. BASEL1, A. G. Senecal2, and K. Racicot2. (1) Lebensmittel Consulting, 10760 W. Co. Rd. 18, Fostoria, OH 44830, (2) U.S. Army Natick Soldier Center, U.S. Army Research, Development & Engineering Command, Kansas St., Natick, MA 01760-5020 Conventional and Modified Atmosphere Packaged whole head lettuce can be affected by exposure to ethylene during normal distribution. Ethylene damage is insidious since ethylene comes from co-storage of ethylene producing crops, vehicle exhaust and heating systems. Better methods for shelf-life extension reducing ethylene damage will provide the commercial sector with a higher quality product and lower economic loss. While Modified Atmosphere Packaging (MAP) can extend life of lettuce, it cannot eliminate the effects of ethylene on postharvest life. MCP (1-methylcyclopropene), a potential ethylene inhibitor was investigated as a method for reduce pinking and decay defects. The objective of this study was to determine the effect of MCP and MAP to extend the storage quality of iceberg lettuce. MCP (AgroFresh®) was sprayed onto the lettuce at the rate of 0.5 g/l, dried at 45 F for 2 hr. and stored at 40 F in MAP bags. Head lettuce was evaluated for texture, L*a*b color, subjective color, decay and edibility. Gases monitored included oxygen, carbon dioxide and ethanol. Chemical constituents monitored included chlorophyll, glucose, total phenols, polyphenol oxidase, and lipase. MCP applications extended the shelf life of lettuce treated after normal distribution but did not show a large effect when MAP packaged directly after hydro cooling. By using MAP packaging and MCP application the effective shelf life is about 4 times longer than commercially produced case packaged lettuce. The pinking scores reflected significantly better quality when MCP protects the lettuce from ethylene damage. Less microbial activity was observed with MCP treated samples versus control. After 2 months, the pH of MCP treated samples was 6.2 versus 5.4 for control. MCP and MAP packaging extended postharvest quality of iceberg lettuce and improved color retention, decreased pinking, and lowered decay during storage when exposed to ethylene. Both treatments increased the shelf life of iceberg lettuce from 1-2 weeks to up to 2 months.
Session 45G, Fruit & Vegetable Products: Vegetables (Fresh)
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