基于pH值响应的甲基红/溴百里酚蓝指示膜的研究

Research on Methyl Red/Bromothymol Blue Indicator Membrane Based on pH Response

摘要: 为开发一种高效可视化食品新鲜度指示标签，本研究以羧甲基纤维素钠、海藻酸钠、卡拉胶为复合成膜基质，甘油为增塑剂，甲基红–溴百里酚蓝复配体系为显色指示剂，采用倾注流延法制备pH响应可视化指示膜，通过单因素试验系统探究了不同指示剂配比下可视化标签的pH响应特性、贮藏颜色稳定性、氨气敏感性，并进一步探究了添加量、多糖基质组成对指示膜机械性能及透光性能的调控规律。结果表明，0.3 mL添加量下甲基红与溴百里酚蓝按3:1复配时指示标签兼具储藏稳定性和碱性响应灵敏度。此外，甘油、卡拉胶与海藻酸钠可定向调控复合膜的力学强度与透光性能，本研究为生鲜食品智能可视化检测的开发提供了实验依据与技术参考。

Abstract: To develop an efficient and visual food freshness indicator label, Sodium carboxymethyl cellulose (CMC), Sodium alginate (SA) and Carrageenan (Car) were used as the composite membranes-forming matrix, Glycerol (Gly) as the plasticizer, and the Methyl red-Bromothymol blue compound system as the color indicator in this study. The pH response characteristics, storage color stability and ammonia sensitivity of the visual labels under different indicator ratios were systematically explored through single-factor experiments. Furthermore, the regulation laws of the addition amount and polysaccharide matrix composition on the mechanical properties and light transmission performance of the indicator film were investigated. The results showed that when Methyl red and Bromothymol blue are compounded at a ratio of 3:1 at an addition amount of 0.3 mL, the indicator label has both storage stability and alkaline response sensitivity. In addition, Gly, Car and SA can directionally regulate the mechanical strength and light transmission performance of the composite film. This study provides experimental basis and technical reference for the development of visual detection of fresh food.