Karakteristik Plastik Indikator sebagai Tanda Peringatan Dini Tingkat Kesegaran Ikan dalam Kemasan Plastik

Abstract

The objective of the research was to characterize early warning indicators (EWI) made of various pH indicators for detecting fish freshness in a plastic packaging. Three types of pH indicator and a mixture of two pH indicators have been employed. The pH indicators were bromothymol blue (BTB), bromocresol green (BCG), bromocresol purple (BCP), and mixture of BCG and methyl red (MR). Sensitivity of the indicators were tested against NH4 OH for 15 minutes and threadfin bream fish (Nemipterus nematophorus) fillet for 15 hours at ambient temperature. Fish sample were taken in every 3 hours for TVB-N and bacterial load analysis. The results showed that BTB indicator showed weak sensitivity in responding NH4 OH and freshness changes of fish fillet. Better sentifity was shown by BCG, BCP and mixture of BCG and MR. Color changes of the BCG, BCP, and mixture of BCG & MR occurred when TVB-N level in the fish fillet was 33.29 ± 4.24 mgN/100 g and bacterial load of 106 cfu/gr. The color change could be easily recognized and identified visually. For designing the EWI, material cost showed less important compared to sensitivity consideration.