Viscusi Gianluca, Lamberti Elena, Angilè Federica, Di Stasio Luca, Gerardi Carmela, Giovinazzo Giovanna, Vigliotta Giovanni, Gorrasi Giuliana
Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy.
Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy.
Int J Biol Macromol. 2025 Feb;291:139085. doi: 10.1016/j.ijbiomac.2024.139085. Epub 2024 Dec 21.
This research is focused on the formulation and testing of green visual pH-sensitive indicators based on natural extracts from Curcuma Longa (CUR) and Lambrusco wine pomace (LAM), an Italian wine variety, incorporated into rice starch/pectin/alginate matrixes for non-destructively detecting shrimps freshness in real-time. The effect of the mixed indicators and their synergic combination on the properties and performances of indicators was investigated. Both the extracts and their combination showed pronounced pH responsiveness. Films were widely characterized in terms of morphological, barrier, spectroscopic, thermal and mechanical properties. The presence of extracts slightly reduced the transparency of the films while the film with both the extracts exhibited the highest Young's modulus (14.17 MPa), lowest moisture content (27.67 %) and a WVP value (0.79 g m m s Pa) intermediate between the Lambrusco extract loaded film and the curcumin based one. Moreover, the pH-sensitive systems showed a noticeable antioxidant activity (96 % for LAM/CUR film) and enhanced antibacterial activity toward E. coli and S. aureus compared to pristine films. Besides, the mixed indicator-based film showed high sensitivity to ammonia (68 %) determining an ΔE value easily detectable by the human eye. Finally, the films were applied as cheap visual indicators for monitoring the freshness of packaged fresh shrimps over time stored at T = 4 °C and T = 25 °C through the colourimetric variation induced by pH changes. The TVB-N value, which was correlated to the microbial count for shrimps over time, reached the rejection limit at 33 h for T = 25 °C and 54 h for T = 4 °C. The colour changes were recorded simultaneously and the turning to deeper colours indicated the decomposition of proteins to organic amines and the spoilage of food. Results show that the produced films provide easily detectable colour changes during food spoilage proving that, being fabricated from natural sources, they represent novel and sustainable tools for multi-purpose intelligent food packaging applications.
本研究聚焦于基于姜黄（CUR）天然提取物和意大利葡萄酒品种蓝布鲁斯科葡萄渣（LAM），将其掺入大米淀粉/果胶/藻酸盐基质中，用于实时无损检测虾的新鲜度，从而制备和测试绿色视觉pH敏感指示剂。研究了混合指示剂及其协同组合对指示剂性能和表现的影响。提取物及其组合均表现出显著的pH响应性。对薄膜的形态、阻隔、光谱、热和机械性能进行了广泛表征。提取物的存在略微降低了薄膜的透明度，而含有两种提取物的薄膜表现出最高的杨氏模量（14.17兆帕）、最低的水分含量（27.67%）以及介于负载蓝布鲁斯科提取物薄膜和姜黄素基薄膜之间的水蒸气透过率值（0.79克·米·毫米·秒·帕）。此外，pH敏感体系表现出显著的抗氧化活性（LAM/CUR薄膜为96%），与原始薄膜相比，对大肠杆菌和金黄色葡萄球菌的抗菌活性增强。此外，基于混合指示剂的薄膜对氨表现出高灵敏度（68%），确定了人眼易于检测到的ΔE值。最后，通过pH变化引起的比色变化，将这些薄膜用作廉价的视觉指示剂，用于监测在4°C和25°C下储存的包装鲜虾随时间的新鲜度。与虾随时间的微生物数量相关的TVB-N值在25°C下33小时和4°C下54小时达到拒收限值。同时记录颜色变化，颜色变深表明蛋白质分解为有机胺以及食物变质。结果表明，所制备的薄膜在食品变质过程中提供了易于检测的颜色变化，证明它们由天然来源制成，是用于多用途智能食品包装应用的新型可持续工具。
