Kanphai Kamonwan, Athipornchai Anan, Sirion Uthaiwan, Suksai Chomchai, Trakulsujaritchok Thanida
Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Burapha University, Chonburi 20131, Thailand.
ACS Omega. 2025 Aug 5;10(32):36104-36114. doi: 10.1021/acsomega.5c03712. eCollection 2025 Aug 19.
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.
本研究提出了一种开发由κ-卡拉胶和聚乙烯醇组成的环保型pH敏感薄膜的新方法，旨在促进对食品新鲜度的实时监测。采用水溶液流延法制备了富含从墨西哥矮牵牛花朵中提取的天然花青素的溶胶-凝胶交联薄膜。通过ATR-FTIR光谱证实了硅氧烷交联的形成以及花青素的成功掺入。扫描电子显微镜显示薄膜形态均匀一致。花青素提取物的掺入增强了薄膜的水蒸气阻隔性能和机械性能，同时赋予了显著的抗氧化活性、紫外线阻隔性能和pH响应性。通过土壤掩埋降解试验验证了薄膜的环境可持续性。值得注意的是，当薄膜在pH值1至12之间变化时，会呈现出从粉红色到浅棕色、棕绿色和黄色的明显颜色转变。当用于监测鲜虾的腐败时，pH敏感薄膜显示出与腐败相一致的明显视觉变化，同时总挥发性碱性氮水平相应升高。总体而言，本研究表明，从墨西哥矮牵牛花朵中提取的花青素的整合显著增强了κ-卡拉胶/聚乙烯醇薄膜的功能特性。所得材料具有理想的特性，包括pH响应性，使其非常适合用于食品包装。因此，这种绿色功能材料作为用于实时监测食品新鲜度的智能包装薄膜具有相当大的潜力。
