Effect of package size and temperature on the volume expansion of flexiblepermeable packages of kimchi, a Korean fermented vegetable

The effect of package size and temperature on package volume expansion was investigated when P71197, a high CO2 permeability film of amorphous nylon l aminate structure, was applied to packaging kimchi, a Korean ethnic ferment ed vegetable. The volume expansion, after an initial lag period, rapidly re ached a maximum and then either decreased or stayed constant. A higher temp erature and a larger package caused greater volume expansion within the exp erimental time span. Based on the criterion of less than or equal to0.8 ml/ g as a tolerable volume change, the appropriate window of package size and temperature has been suggested. The expanded volume was found to consist ma inly of CO2 produced from kimchi, resulting in higher CO2 concentrations fo r higher temperatures and larger package sires. The effect of package size on the volume expansion and gas composition can be explained by the differe nces in the ratio of surface area to filled weight among the packages. The effect of storage temperature can be explained by the difference in activat ion energy between CO2 production from the kimchi and gas permeation throug h the film. Copyright (C) 2001 John Wiley G Sons, Ltd.