Use of color indicators as an active packaging system for evaluating kimchi fermentation

Color indicators for kimchi (fermented vegetable products in Korea) packaging have been newly developed to evaluate the degree of fermentation of kimchi products non-destructively during storage and distribution. Kimchi fermentation was assessed for titratable acidity (TA), and color changes of the indicators were measured and expressed as Hunter values as well as total color difference (TCD). TCD values of bromocresol purple (BP) type indicator (containing BP as a chemical dye) ranged 27-33 and were much more than those of methyl red (MR) type (containing MR). A kinetic approach was used to correlate the response of the indicators to the changes in kimchi fermentation. Color changes of both BP and MR type indicators correlated well with TA values of kimchi. The present results suggest that color indicators be applicable to kimchi products as an active packaging system for monitoring their ripeness. (C) 2000 Elsevier Science Ltd. All rights reserved.