Quality of packaged romaine lettuce hearts exposed to low-dose electron beam irradiation

We investigated the effects of low-dose electron beam irradiation (1.0, 1.5 and 3.2kGy) on the quality of commercially prepackaged fresh romaine lettuce hearts. The impact of the irradiation treatment on the functionality of the package was also evaluated. Irradiated samples showed slight changes in color, but these changes were not significantly different (P >0.05) from the nonirradiated (control) samples. Sample firmness decreased by 49.58% (leaves) and 29.13% (ribs), as the dose level increased. Sensory attributes such as overall quality, color, sogginess, and off-flavor were found less acceptable at the higher dose level. Irradiation affected the respiration rates inside the packages, with lower (10.38%) O₂ and higher CO₂ levels than the control. Irradiation at 1.5 and 3.2kGy dose levels improved the oxygen barrier capability of the low-density polyethylene (LDPE) bags (7.67% and 4.48%, respectively). Water vapor permeability was unaffected at all the irradiation dose levels. The stiffness of LPDE films did not change due to irradiation treatment. Results from sensory evaluation of produce overall quality suggest a potential fungicidal effect of low-dose irradiation (1.0kGy) of packaged romaine lettuce hearts without altering the overall quality of the produce as well as the LDPE-packaging characteristics.