The characterization of time temperature indicator with varying concentrations of Roselle (Hibiscus sabdariffa L.) extract and immobilization times

Anthocyanin is a colour pigment that has the potential as an indicator for making a Time Temperature Indicator (TTI). This is because anthocyanins are stable at low temperatures and change colour due to temperature changes (thermochromic). In this study, an analysis was carried out to determine the combination of various concentrations of roselle extract and immobilization time on the colour stability of TTI. The combined treatments used Randomized Group Design with roselle extract concentration factors of 10%, 12.5% and 15% and immobilization time factors of 1, 2 and 3 h, with three replications. Then the roselle anthocyanin absorption and colour stability of a TTI was observed. Variable measurements were carried out 3 times and using analysis of variance with a value of α 5% followed by DMRT test with α 5% if it was significantly different. The evaluation of colour stability was analysed using linear regression. The selected TTI in this study was a combination of 15% concentration and 2 h of immobilization. This treatment had a total absorption value of 2.14 g; total anthocyanin of 23.58 µg/mL, L* colour of 72.64; a* colour of 0.3; b* colour of 7.64 and ΔE of 4.93. Evaluation of TTI anthocyanin stability at 50⁰C had the highest decrease in a* value of 4.423 and the lowest retention value at 12 h of observation time of 85.6%. These results demonstrate the feasibility of using anthocyanin-based TTIs for monitoring temperature changes, highlighting their potential application in food safety and quality control.