Interactive influence of decision criteria, packaging film, storage temperature and humidity on shelf life of packaged dried vegetables

Abstract

In an attempt to get the overall picture of shelf life dynamics of packaged dried foods, a mathematical simulation model consisting of differential equations of water vapor transmission and quality change was established and solved numerically through the interactive relationships of moisture sorption isotherm, package water vapor permeability and quality deterioration kinetics to predict moisture content and quality changes throughout storage. Estimated shelf lives based on moisture increase and primary quality change as the decision criteria were examined for dried onion flakes, cabbage and green beans packaged in a hydrophobic polyolefin film and a hydrophilic biobased film with different moisture sensitivities and then stored at temperatures of 20−40 °C and relative humidities (RH) of 60–100 %. The range of shelf life estimates varied greatly with product and was affected by the moisture and quality criteria limit values. In general, the temperature effect on shelf life was greater than that of humidity over the ranges examined. The magnitude of the difference in shelf life between moisture content and quality index used as criteria was greater with the less permeable hydrophobic polyolefin film. Accelerated shelf life testing at higher temperatures and humidities was shown to have a greater impact on the estimated shelf life when using specific quality criteria rather than moisture content. Use of moisture-sensitive packaging film accelerated deterioration compared to hydrophobic packaging film. The proposed comparative methodology is helpful for designing accelerated shelf life testing of dried foods.