The use of Na2CO3-based CO2 absorbent systems to alleviate pressure buildup and volume expansion of kimchi packages

Kimchi, a lactic acid fermented vegetable dish, is usually packaged without pasteurisation and produces a lot of carbon dioxide inside its package during storage and marketing. In order to develop a kimchi packaging system with controlled pressure and volume, various chemical CO2 absorbents were compared for use in the packages. Na2CO3 was shown to have a good potential for absorbing CO2 in kimchi packages under conditions with an adequate water supply. The properties of Na2CO3 as a CO2 absorber were characterised and then used for designing a new CO2 absorbent system for kimchi packages. The water vapour and CO2 transmission rates of the sachet and plastic sheet containing Na2CO3 were used as a useful design variable to control the CO2 absorption rate. Na2CO3 was also combined with zeolite in order to control the CO2 absorption rate and maintain equilibrium conditions. When the combined CO2 absorbing material was fabricated into a sachet or expanded polystyrene sheet and then attached inside the kimchi package, the reduced pressure buildup and volume expansion were attained with proper levels of CO2 partial pressure. (C) 2002 Elsevier Science Ltd. All rights reserved.