Effect of Modified Atmosphere Packaging on the Mechanical Properties of Lettuce During Shelf Life in Cold Storage

Abstract Lettuce is a perishable vegetable that its shelf life is limited by detrimental texture changes and enzymatic activities during postharvest storage. One of solutions that can be used in storage and distribution of this product is modified atmosphere packaging (MAP). But its effects on the mechanical properties of the product have not been studied. This information would be beneficial in inspection of eating quality and later processing such as cutting and shredding. This research aimed to study effect of active MAP technology on the postharvest mechanical properties of lettuce at different storage periods. It was found that MAP had a significant effect on the tension property of the lettuce leaf. MAP treatment preserved the brittleness of the specimens during storage, but the control ones lost their brittleness and tolerated greater tension. Stiffness and rupture energy were significantly affected by MAP with P values of 0.01 and 0.05, respectively. Also, stiffness of the MAP-treated samples was higher than the control at the same storage time. The findings are due to reducing respiration, transpiration and bacterial growth by MAP which delays nutrient decomposition and maintains the original color and texture.