Sensitivity determination of indicator paper as smart packaging elements in monitoring meat freshness in cold temperature

Placing indicators on the packaging is a solution that can be used to monitor the quality of food packaged. The application of indicators to packaging technology is known as smart packaging. Filter paper is one paper that can be used as an intelligent packaging element that functions as an indicator because it can absorb pH indicator solutions that are applied to monitor the freshness of meat. The research objective was to make smart packaging indicators that have high sensitivity to amine compounds such as ammonia, indole, and cadaverine; thus, it can monitor the quality of meat stored at cold temperatures. The filter paper used was Whatman number 1 filter paper which soaked with pH indicators namely Phenol Red (PR); Phenol Red (PR) + Bromothymol Blue (BTB), and Bromothymol Blue (BTB). Smart packaging was applied to packaged fresh meat and stored in cold temperatures. During the storage, the results of the microbial and enzymatic decomposition of proteins and amino acids in fresh meat such as ammonia, indole and cadaverine compound accumulated in smart packaging indicators and cause color changes in the paper indicator. The results obtained indicated that the utilization of filter paper with PR + BTB immersion had a significant sensitivity of color change that can be used to observe changes in the quality of fresh meat stored in cold temperatures.