Colorimetric Strip Based on Anthocyanin Extracts from Alugbati (Basella alba L.) Fruits for Monitoring Shrimp Freshness

The rising demand for smart packaging drives interest in anthocyanins which changes colors depending on different conditions. Anthocyanins were extracted from Alugbati fruits using acidified ethanol, yielding a total monomeric anthocyanin content (TMAC) of 223.59 mg/L. The extract was incorporated into chitosan/polyvinyl alcohol films, and its interaction with the polymer matrix was evaluated via FTIR spectroscopy. The developed films were tested for sensitivity to pH conditions and ammonia vapor. Results indicated that C/PVA10 film demonstrated color change from reddish-pink to yellow in alkaline conditions. Exposure to ammonia vapor caused notable color transitions from purple (1 hr) to reddish-brown (4 hrs) and pale brown (7 hrs), with corresponding increases in SRGB% values, indicating progressive shrimp spoilage. FTIR analysis confirmed interactions between the anthocyanin and chitosan matrix. The findings suggest that colorimetric film from anthocyanin extracts of Alugbati fruits have significant potential as freshness indicators for shrimp packaging