Al-Ati Tareq, Hotchkiss Joseph H
Department of Food Science, Stocking Hall, Cornell University, Ithaca, New York 14850, USA.
J Agric Food Chem. 2003 Jul 2;51(14):4133-8. doi: 10.1021/jf034191b.
Modified atmosphere packaging (MAP) is commercially used to increase the shelf life of packaged produce by reducing the produce respiration rate, delaying senescence, and inhibiting the growth of many spoilage organisms, ultimately increasing product shelf life. MAP systems typically optimize O(2) levels to achieve these effects while preventing anaerobic fermentation but fail to optimize CO(2) concentrations. Altering film permselectivity (i.e., beta, which is the ratio of CO(2)/O(2) permeation coefficients) could be utilized to concurrently optimize levels of both CO(2) and O(2) in MAP systems. We investigated the effect of modifying film permselectivity on the equilibrium gas composition of a model MAP produce system packaged in containers incorporating modified poly(ethylene) ionomer films with CO(2)/O(2) permselectivites between 4-5 and 0.8-1.3. To compare empirical to calculated data of the effect of permselectivity on the equilibrium gas composition of the MAP produce system, a mathematical model commonly used to optimize MAP of respiring produce was applied. The calculated gas composition agreed with observed values, using empirical respiration data from fresh cut apples as a test system and permeability data from tested and theoretical films. The results suggest that packaging films with CO(2)/O(2) permselectivities lower than those commercially available (<3) would further optimize O(2) and CO(2) concentration in MAP of respiring produce, particularly highly respiring and minimally processed produce.
气调包装（MAP）在商业上用于通过降低农产品呼吸速率、延缓衰老以及抑制许多腐败微生物的生长来延长包装农产品的货架期，最终增加产品的货架寿命。MAP系统通常会优化氧气水平以实现这些效果，同时防止厌氧发酵，但未能优化二氧化碳浓度。改变薄膜的渗透选择性（即β，它是二氧化碳/氧气渗透系数的比值）可用于同时优化MAP系统中二氧化碳和氧气的水平。我们研究了改变薄膜渗透选择性对包装在装有改性聚（乙烯）离聚物薄膜的容器中的模型MAP农产品系统平衡气体组成的影响，这些薄膜的二氧化碳/氧气渗透选择性在4 - 5和0.8 - 1.3之间。为了将渗透选择性对MAP农产品系统平衡气体组成影响的实验数据与计算数据进行比较，应用了一个常用于优化呼吸农产品MAP的数学模型。以鲜切苹果的实验呼吸数据作为测试系统，并使用测试薄膜和理论薄膜的渗透数据，计算得到的气体组成与观测值相符。结果表明，二氧化碳/氧气渗透选择性低于市售产品（<3）的包装薄膜将进一步优化呼吸农产品MAP中的氧气和二氧化碳浓度，特别是高呼吸速率和最少加工的农产品。
