Objective   Effect of different concentration of CO₂ in confined environment on quality of sesame was studied for a green and economic storage technology of the food material.

  Method  Sesame were packed in aluminum foil bags under vacuum and fill with CO₂ gas and air in various proportion using a gas mixing device. The changes on 5 indicators, i.e., acid, peroxide, and iodine values, and crude fat and protein contents, of the stored sesame were determined every 2 months according to the national standard method.

  Result   In storage, the acid and peroxide values of the bagged sesame increased gradually with increasing time. After 6 months, the acid value drastically increased reaching up to 0.700 0 meq·kg⁻¹. Then, the increased slowed down till the end. The upward trend on peroxide value was less dramatic. When a bag was filled with more than 50% of CO₂, the rises on acid and peroxide became slower than when less CO₂ gas was used; the iodine value decreased slightly but not significantly; and, the crude fat and protein contents decreased gradually. And, the higher CO₂ proportion in the package, the slower the decrease became. When a bag was filled 100% with CO₂, the decline on fat reduced by 0.42% and that on protein by 0.28%. Comparing to control, which had 3.05% decrease on fat and 15.02% on protein, the effects were statistically significant (P ＜0.05).

  Conclusion  Oxygen in package significantly affected the quality of the stored sesame. By including more than 50% of CO₂ gas in a bag, the increases on acid and peroxide values were significantly reduced, and the reduction of fat and protein delayed, and the onset of rancidity of the sesame postponed. In other words, the original quality of the sesame could basically be maintained at a premium level for a year at room temperature by the controlled atmosphere storage with CO₂.