The Use of Tragacanth As a Gelling Agent in Roselle Flower Extract Based Radiochromic Indicators

Gamma irradiation techniques have been used in various fields, such as sterilizing medical equipment and food products. In such a process, monitoring the dose of radiation using radio radiochromic dosimeter is important to guarantee the accuracy of the radiation dose absorbed by the irradiated materials. Radio chromic dosimeters usually consisted of radiation-sensitive dyes that could change colors when exposed to radiation. In this research, natural dyes in the form of anthocyanins obtained from roselle flower extract (Hibiscus sabdariffa L.) have been used as radio chromic indicators. The radio chromic indicators have been made in liquid using water solvent and gel using a tragacanth gelling agent. Each radiochromic indicator's pH values varied between 2 and 11 using NaOH and HNO3 solutions. All radio chromic indicators were then gamma irradiated using a Co-60 radiation source and tested for stability at 8°C under closed storage conditions. The characterization was performed using UV Vis spectrophotometry. The results showed that roselle flower extract was sensitive to gamma radiation as indicated by decolorization, and their sensitivity increased when made in the form of gel at pH 2 and 5. The stability test also showed that the anthocyanin content was stable after being maintained for 28 days in a closed storage at 8°C. With such differences in sensitivity of the roselle flower extract when used in either liquid or gel solution, the radio chromic indicators should find wide application in the future, depending on the radiation doses given to the solutions.