Thanida Trakulsujaritchok

This research presents a novel approach for the development of environmentally friendly and pH-sensitive films composed of kappa-carrageenan and poly-(vinyl alcohol), designed to facilitate real-time monitoring of food freshness. Sol-gel cross-linked films, enriched with natural anthocyanins extracted from Mexican petunia flowers, were prepared using an aqueous solution casting method. The formation of siloxane cross-linking and the successful incorporation of anthocyanins were confirmed by ATR-FTIR spectroscopy. Scanning electron microscopy revealed homogeneous and uniform film morphology. The incorporation of the anthocyanin extract enhanced the water vapor barrier performance and mechanical properties of the films, while imparting notable antioxidant activity, UV-blocking, and pH responsiveness. The environmental sustainability of the films was verified through a soil burial degradation test. Notably, the films exhibited distinct color transitions, shifting from pink to light-brown, brownish-green, and yellow, when subjected to pH changes between 1 and 12. When employed to monitor the spoilage of fresh shrimp, the pH-sensitive films revealed clear visual changes coinciding with spoilage, along with a corresponding rise in total volatile basic nitrogen levels. Overall, this study demonstrates that the integration of anthocyanins extracted from Mexican petunia flowers significantly enhances the functional properties of kappa-carrageenan/poly-(vinyl alcohol) films. The resulting materials exhibit desirable characteristics, including pH responsiveness, making them well-suited for use in food packaging. Consequently, this green functional material holds considerable promise as smart packaging films for the real-time monitoring of food freshness.

A green, convenient, and metal-free methodology for synthesizing primary aniline-based indolylmethanes has been developed through a sequential one-pot, three-component aza-Friedel–Crafts reaction. This approach employs a wide range of commercially available aldehydes, primary anilines, and indoles, catalyzed by a Brønsted acidic ionic liquid in an aqueous medium. A variety of desirable products were obtained in high yields (up to 98%). The process was successfully demonstrated on a gram scale, confirming its scalability and reproducibility while maintaining high yields. Additionally, the catalyst exhibited remarkable recyclability, retaining high catalytic efficiency over three cycles without a significant loss of activity.