Devlieghere F, Debevere J, Van Impe J
Department of Food Technology and Nutrition, University of Gent, Belgium.
Int J Food Microbiol. 1998 Aug 18;43(1-2):105-13. doi: 10.1016/s0168-1605(98)00101-9.
The effect of modified atmosphere packaging can mainly be attributed to the bacteriostatic action of CO2. The dissolved CO2 in the water-phase of a food product is strongly dependent on several intrinsic and extrinsic parameters and will determine the effectiveness of a modified atmosphere packaging configuration. The effect of pH, gas/product ratio, initial %CO2 in the gas-phase, lard content and storage temperature on the amount of dissolved CO2 was screened in a preliminary experiment. The initial CO2-concentration in the gas-phase and the gas/product ratio turned out to be the two major factors determining the amount of dissolved CO2. The initial pH also determined significantly the final CO2-concentration in the broth. Temperature and lard content were shown to have only a minor effect on the amount of dissolved CO2 compared to the above mentioned parameters. This demonstrates the importance of the packaging configuration in the effectiveness of a modified atmosphere. In a second step, a model was constructed to predict the amount of dissolved carbon dioxide in modified BHI-broth as a function of the gas/product ratio, the initial CO2-concentration and the temperature by means of Response Surface Methodology (RSM). A second equation was also derived based on Henry's law and was shown to be a powerful tool in the quantification of the effect of intrinsic and extrinsic parameters on the CO2-solubility in food products. The possibility of the use of the concentration of dissolved CO2 in the water-phase as a determinative factor for the inhibitory effect of modified atmospheres was examined on Pseudomonas fluorescens. Growth curves at 7 degrees C of P. fluorescens in different packaging configurations (initial %CO2 and gas/product ratio) resulting in equal amounts of dissolved CO2 were compared. P. fluorescens was shown to be similarly inhibited by equal amounts of dissolved CO2-concentrations, independent of the packaging configuration. This demonstrates the potential of the application of the concentration of dissolved CO2 in the water-phase as a parameter to characterise a modified atmosphere and its inhibition of certain microorganisms.
气调包装的效果主要可归因于二氧化碳的抑菌作用。食品水相中的溶解二氧化碳强烈依赖于几个内在和外在参数，并将决定气调包装配置的有效性。在初步实验中筛选了pH值、气/产品比、气相中初始二氧化碳百分比、猪油含量和储存温度对溶解二氧化碳量的影响。结果表明，气相中的初始二氧化碳浓度和气/产品比是决定溶解二氧化碳量的两个主要因素。初始pH值也显著决定了肉汤中最终的二氧化碳浓度。与上述参数相比，温度和猪油含量对溶解二氧化碳量的影响较小。这证明了包装配置在气调有效性中的重要性。第二步，通过响应面法（RSM）构建了一个模型，以预测改良脑心浸液肉汤中溶解二氧化碳的量与气/产品比、初始二氧化碳浓度和温度的函数关系。还根据亨利定律推导了第二个方程，结果表明该方程是量化内在和外在参数对食品中二氧化碳溶解度影响的有力工具。研究了将水相中溶解二氧化碳的浓度用作气调抑制作用的决定性因素的可能性，以荧光假单胞菌为研究对象。比较了荧光假单胞菌在7℃下，在不同包装配置（初始二氧化碳百分比和气/产品比）下，导致溶解二氧化碳量相等时的生长曲线。结果表明，等量的溶解二氧化碳浓度对荧光假单胞菌的抑制作用相似，与包装配置无关。这证明了将水相中溶解二氧化碳的浓度用作表征气调及其对某些微生物抑制作用的参数的应用潜力。
