Packaging Group, Instituto de Agroquímica y Tecnología de Alimentos, CSIC, Av. Agustin Escardino 7, 46980 Paterna, Spain.
Sensors (Basel). 2019 Oct 28;19(21):4684. doi: 10.3390/s19214684.
A chromatic sensor has been designed for the detection of oxygen in package headspace. The sensor is based on the redox change of methylene blue (MB) to its leuco form. Its formulation includes the pigment, glycerol, as a sacrificial electron donor, TiO, as a photocatalyst and ethylene-vinyl alcohol copolymer (EVOH), as a structural polymer matrix. The final sensor design that allows its manufacture by conventional printing and laminating technologies consists of the sensing polymer matrix (MB-EVOH) sandwiched in a suitable transparent multilayer structure. The outer layers protect the sensor from the external atmosphere and allow visualization of the colour. The inner layer is sufficiently opaque to facilitate sensor reading from the outside, is thick enough to avoid direct contact with food (functional barrier), and is oxygen-permeable to expose the sensing material to the internal package atmosphere. In the absence of oxygen, the sensor becomes white by irradiation with halogen lamps in less than 60 s. All components are substances permitted for food contact except the pigment, but specific migration analysis showed no trace of migration thanks to the functional barrier included in the design.
一种用于检测包装顶空氧气的比色传感器已经设计完成。该传感器基于亚甲蓝（MB）向其无色形式的氧化还原变化。其配方包括颜料、甘油，作为牺牲电子供体，TiO2 作为光催化剂，以及乙烯-乙烯醇共聚物（EVOH），作为结构聚合物基质。最终的传感器设计允许通过常规的印刷和层压技术制造，由夹在合适的透明多层结构中的传感聚合物基质（MB-EVOH）组成。外层保护传感器免受外部大气的影响，并允许观察颜色。内层足够不透明，以方便从外部读取传感器，足够厚以避免与食物直接接触（功能屏障），并且氧气可渗透，以使传感材料暴露于内部包装气氛中。在没有氧气的情况下，传感器在不到 60 秒的时间内通过卤素灯照射变成白色。除了颜料外，所有成分都是允许与食品接触的物质，但由于设计中包含的功能屏障，特定的迁移分析显示没有迁移痕迹。
