Modified Atmosphere Packaging of Cut Welsh Onion: Effect of Micro-Perforated Polypropylene Film Packaging on Chemical Components and Quality Stability of the Vegetable.

Abstract

The chemical components and quality stability of pre-cut Welsh onion wrapped in an unperforated or micro-perforated orientated polypropylene (OPP) film package were evaluated during storage at 10°C. The concentration of oxygen (O2) in the unperforated OPP package decreased rapidly to 2% while that of carbon dioxide (CO2) increased. Therefore, the onion underwent anaerobic respiration, ethyl alcohol was produced and some of the chemical components were lost. Moreover the cellular tissue of the vegetable became water-soaked. The O2 concentration in the OPP film package with too many micro-perforations decreased slightly, so that ethyl alcohol was not detected but there was a loss of chemical components. The quality of the product was diminished and the onion was unmarketable after 6 days of storage. For cut Welsh onion packed in perforated OPP film (with 24 micro-perforations), the O2 concentration in the package was not as low as in the modified atmosphere packaging for onion, but did decrease to 10%. Ethyl alcohol could not be detected and there was no or only slight loss of chemical components, so that the onion was still marketable after 6 days of storage.