Changes in Quality of Cold-Pressed Rapeseed Oil with Sinapic Acid Ester-Gelatin Films during Storage

In recent years, cold-pressed rapeseed oil (CPRO) has become an attractive health-beneficial product and a promising alternative to olive oil. However, a high level of unsaturated fatty acids renders a CPRO more susceptible to oxidative deterioration. Therefore, the effect of new gelatin strips with polyvinyl alcohol (GEL-PVA) and sinapic acid esters (ethyl sinapate-ESA; octyl sinapate-OSA, and cetyl sinapate-CSA) on the oxidative stability, antioxidant activity (AA), and total phenolic content (TPC) in CPRO samples was analyzed during accelerated storage. In addition, the antioxidant properties of the GEL-PVA films loaded with sinapic acid esters were studied. Interestingly, the CPRO stored in an amber glass marasca bottle containing GEL-PVA-ESA strips for 14 days had the highest AA, while the antioxidant potential was the lowest for oil without film strips. Furthermore, oil samples stored in bottles containing GEL-PVA-ESA and GEL-PVA-OSA strips for 14 days had higher antioxidant properties than the AA and TPC in fresh CPRO. Moreover, synchronous fluorescence (SF) spectroscopy and excitation-emission matrix (EEM) fluorescence spectroscopy were applied for the evaluation of changes in the main fluorescent components in CPRO samples during the accelerated storage. Overall, this study revealed that GEL-PVA films incorporated with sinapic acid esters enhanced the antioxidant potential of CPRO and delayed oxidative degradation by releasing amphiphilic antioxidants into the oil.