| abstract |
(57) [Summary] [PROBLEMS] To provide a food quality indicator, a food wrapping paper, and a food packaging container capable of accurately distinguishing the maturity of food from the outside without opening the packaging. An indicator which changes color according to a pH value, a resin monomer having a double bond for fixing the indicator, and a polymer hydrogel matrix comprising a crosslinking agent, A food quality indicator comprising: a semi-permeable membrane that selectively permeates only ions and a solvent; and a matrix attached to at least one location on one surface of the semi-permeable membrane. Also, food wrapping paper and food packaging containers having the food quality indicator. |