基于pH驱动法的姜黄素/明胶指示膜制备、表征及对刀额新对虾的新鲜度指示

Preparation and characterization of curcumin/gelatin indicator film based on pH-driven method and freshness indication of shrimp

中文关键词:  pH  驱动  姜黄素  明胶  指示膜  刀额新对虾

英文关键词:pH-driven method  curcumin  gelatin  indicator film  Metapenaeus ensis

中文摘要:

      目的 制备姜黄素/明胶(curcumin/gelatin, Gel/Cur)指示膜并应用于刀额新对虾(Metapenaeus ensis)的新鲜度指示, 拓宽姜黄素作为pH指示剂在水产品新鲜度可视化检测中的应用。方法 以明胶为成膜基质, 姜黄素为指示剂, pH驱动法制备指示膜, 比较不同成膜pH对指示膜微观结构、机械性能及颜色响应能力等指标的影响, 并将Gel/Cur指示膜应用于刀额新对虾新鲜度检测。结果 pH驱动法显著提高了姜黄素和明胶的相容性, 傅里叶变换红外光谱分析表明, 姜黄素在pH驱动过程中主要通过氢键和疏水相互作用包埋于明胶网络中。X射线衍射和扫描电子显微镜结果显示, 姜黄素在pH驱动过程中以无定形形态存在, 而不同成膜pH导致了姜黄素在指示膜内的溶解性差异, 影响了指示膜的微观结构。当最终成膜液pH=7.0时, 指示膜具有最优异的柔韧性(断裂伸长率为49.46%)、阻隔性能[水蒸气透过率为(18.64±0.31)×10?10 g/(m·Pa·s)]和颜色响应能力。此外, 将性能最优的指示膜用于刀额新对虾(4℃)新鲜度指示, 在实验期间指示膜出现明显的颜色变化, 并对应鲜度等级划分, 相关性分析表明指示膜色差值(ΔE)与pH、挥发性盐基氮含量存在显著正相关(R2=0.92806), 表明指示膜能够对鲜虾的新鲜度进行可视化实时监测。结论 pH驱动法制备的Gel/Cur指示膜可以作为水产品新鲜度实时检测的智能包装。

英文摘要:

      Objective To prepare curcumin/gelatin (Gel/Cur) indicator film and apply it to the freshness indicator of Metapenaeus ensis, and broaden the application of curcumin as a pH indicator in visualizing the freshness of seafood. Methods Gelatin was used as the film-forming substrate and curcumin was used as the pH indicator. The pH-driven method was used to prepare the indicator film and compare the effects of different pH values on the microstructure, mechanical properties and color responsiveness of the indicator film, and the Gel/Cur indicator film was applied to the freshness testing of shrimp. Results The pH-driven method significantly improved the compatibility of curcumin and gelatin. Fourier transform infrared spectroscopy analysis showed that curcumin was mainly encapsulated in the gelatin network through hydrogen bonding and hydrophobic interactions during the pH-driven process. X-ray diffraction and scanning electron microscopy results showed that curcumin existed in an amorphous form during pH drive process. However, the solubility of curcumin in the indicator film was different due to different pH formation, which affected the microstructure of the indicator film. When the final film-forming solution was pH=7.0, the indicator film had the best flexibility (elongation at break of 49.46%), barrier property [water vapor permeability of (18.64±0.31)×10?10 g/(m·Pa·s)] and color response. In addition, the best-performing indicator film was used to indicate the freshness of shrimp (4℃), and a significant color change was observed during the experimental period, corresponding to the freshness class classification. Correlation analysis showed a significant positive correlation between the indicator film ΔE and pH and total volatile basic nitrogen (R2=0.92806), indicating that the indicator film was able to visualize the freshness of shrimp in real time. Conclusion The Gel/Cur indicator membrane prepared by pH-driven method can be used as a smart package for real-time freshness detection of seafood.