Effect of High Oxygen Modified Atmosphere Packaging on Fresh-Cut Onion Quality

The high oxygen modified atmosphere packaging is effective to the vegetable, but there is rare study about its effect to fresh-cut onion. This work investigates the effect of high oxygen modified atmosphere packaging on the quality of fresh-cut onion at room temperature. In order to study the effect of different oxygen concentration on the quality of fresh-cut onion, onion slices on the polypropylene (PP) trays were packaged in a package of 18 X 24cm(2) high-barrier film of 70 mu m thickness. Onion slices were stored in five different modified atmospheres which including 100% O-2, 95%O-2/5%CO2, 80%O(2)120%CO2, 75%O-2/25%CO2 and air. The physics, chemistry and microbe characteristics were selected as primary quality indexes. The study showed that the weight loss and respiration rate of high oxygen modified atmosphere packagings were remarkable smaller than the air packaging during the storage; The total reducing sugar decreased during the storage, but the package with 80%O-2/20%CO2 reduced slower relatively; The total titratable acid increased slower in the high oxygen than in the air; The total soluble solid content also reduced during the storage, but there was no remarkable difference in the different modified atmosphere packagings; The total bacterial count of all the packages increased slower in the first 2 days, after that the total bacterial count of fresh-cut onion in the high oxygen modified atmosphere packaging increased remarkable slowly compared with in the air. It showed that the total bacteria counts of the high oxygen modified atmosphere packaging with 80%O-2/20%CO2 increased slowest relatively, and the total bacteria counts increased to 10(5) CFU/g after 7 days. All the fresh-cut onions besides the high oxygen modified atmosphere packagings with 80%O-2/20%CO2 and 100% O-2 were gently rotten after 4 days. Summarizing all the primary quality indexes of the fresh-cut onion during the storage, the high oxygen modified atmosphere packaging with 80%O-2/20%CO2 could obtain longer shelf-life at room temperature.