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Resumen:
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Soft farmhouse cheeses made from pasteurized milk and having high moisture content are common craft products in various countries, including Ireland. These cheeses have limited shelf-life, approximately 4 weeks when stored at 4 °C, in most cases requiring controlled refrigerated conditions during distribution and sale. The objective of this work was to develop new packaging systems to extend their shelf-life based on Modified Atmosphere Packaging (MAP) and Active Packaging (AP) technologies. MAP is a well-established technique in which the gases surrounding a product are altered resulting in an atmospheric composition different from that of air. The design of an MA package depends on a number of variables: the characteristics of the product, its weight, the recommended atmosphere composition, the permeability of the packaging materials to gases and its dependence on temperature and the gas exchange rate of the product as affected by different gas composition and temperature. Therefore, the first step to design a MA package for cheese was to determine its gas exchange rate. The effect of O2, CO2 and temperature on gas exchange rate of whole soft cheese (camembert-type) was studied yielding the conclusion that CO2 effect was negligible while temperature had the highest influence. The effect of O2 concentration on the gas exchange rate was found to be well described by a Michaelis-Menten equation whereas an Arrhenius equation was used to fit the effect of temperature. Combining the effect of O2 and temperature, a global model was developed and validated.
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