Utilisation of gambir tannins as a Freshness Indicator in smart food packaging

Gambir is one of the extracts from the Uncaria gambir plant that is segmented, dried, and then can be molded into various shapes. The components used for gambir extract come from the leaves and twigs of the plant, which contain high amounts of catechins and tannins. These tannins can be used as medicine and dyes and are also used in industry as wood adhesives. This tannin dye made from gambir can be used as a colour indicator that shows the condition of foodstuffs on an intelligent packaging indicator. The colour indicators used from tannins can provide information on discolourations that occur in foodstuffs; these changes are used as a means of detecting and indicating the shelf life of foodstuffs and whether these foods are still safe to eat. This study investigates the use of gambir tannin in an indicator strip by analysis of FTIR spectroscopy, pH, storage testing, and colour measurement using the RGB method. This was applied to tuna fish fillet foodstuffs which were evaluated through Total Volatile Base Nitrogen (TVBN) and pH analysis. This study showed that the total tannins were 27.52 % and phenols were 178.7 mg GAE/g. For Colour indicators with tannin concentrations of 1 %, 3 % and 5 %, there is a bend of the aromatic C--C functional group at wave number 1521.84 cm-1, which indicates the presence of tannin compounds in the colour indicator. After dipping the strip indicators into solutions with pHs of 3, 5, 7, and 9, the indicators darken in colour to show a higher pH. Indicators with a tannin concentration of 1 % are better because they undergo discolouration and are more stable than indicators with tannin concentrations of 3 % and 5 %. Storage of fish fillets for five days at a temperature of 5-7 degrees C showed that the pH value decreased while the TVBN level increased, and the colour indicator became darker.