A PVA film for detecting lipid oxidation intended for food application

Lipid oxidation is a big contributor to food deterioration. The objective of this study was to develop an intelligent film for visually detecting lipid oxidation, based on the colorimetric reaction of Schiff’s reagent and aldehydes—the major volatile lipid oxidation products. A polyvinyl alcohol (PVA) film containing Schiff’s reagent was formed, with the elasticity modulus of 0.27 MPa and the tensile strength of 19.17 MPa. The PVA film was exposed to various concentration (0–7.02 mg/L) of gaseous hexanal—the major aldehyde formed during lipid oxidation, the color change of the PVA film was measured by CIELab scale. The color of PVA film changed from colorless to purple after exposure to hexanal. As the hexanal concentration increased, the color change of the PVA film was more obvious. A linear relationship was found between the hexanal concentration and the color change. The developed PVA film could be an indicator for lipid oxidation of food when incorporated as a minor component of food packaging.