(50) Effect of Delayed MA Packaging and Packaging Film on Quality Maintenance of Fresh-cut Iceberg Lettuce

Abstract

Modified atmosphere (MA) packaging has been used to maintain quality of fresh-cut lettuce, but O2 depletion and excessive CO2 accumulation can be injurious. This study was conducted to evaluate the effect of delayed MA packaging using three different films on quality maintenance of fresh-cut iceberg lettuce. Iceberg lettuce leaves were sliced, washed, dried, and placed for 0, 5, 10, and 15 hours under air atmosphere at 5 °C. Samples were packaged with 2.9 and 16.6 pmol·kg·Pa·s, oxygen transmission rate (OTR) films and microperforated film (P-plus), and stored for 12 days at 5 °C. Results indicated that delayed packaging affected gas composition (O2 and CO2), fermentative volatile production, off-odor, color, and tissue electrolyte leakage. With 2.9 OTR film, longer delayed time maintained quality by inhibiting off-odor development and the accumulation of ethanol. However, delayed packaging was not effective in maintaining quality of samples packaged with 16.6 OTR film and P-plus film. Regardless of delayed time, all 16.6 OTR-packaged samples had severe discoloration after 7 days of storage. All delayed treatments packaged with P-plus film attained the desired O2 (3–5 kPa) and CO2 levels (10–12 kPa) from day 9 to the end of storage. A 15-hour delayed packaging into packages prepared from 2.9 OTR film and samples packaged with P-plus film maintained quality by inhibiting off-odor development. The results indicate that delayed packaging could be an alternative method when fresh-cut lettuce is packaged with low OTR films.