Response Surface Methodology and UPLC-QTOF-MSE Analysis of Phenolic Compounds from Grapefruit (Citrus✕ Paradisi) by-Products as Novel Ingredients for New Antioxidant Packaging

The present work reports an experimental study on the optimization of phenolic compounds extraction from Citrus ✕ paradisi peels and the development of active packaging. Response surface methodology (RSM) was applied to investigate the effect of microwave-assisted extraction (MAE) for the recovery of total phenolic compounds (TPC). The TPC in the optimized extract were 31.10 mg gallic acid equivalent/100 g of dry weight (mg GAE/100 g dw) with strong antioxidant capacity. The bioactive compounds in the optimized extract were determined by ultrahigh performance liquid chromatography coupled to quadrupole time-of-flight with high energy mass spectrometry (UPLC-QTOF-MSE). Forty-five compounds were detected and qualified. The optimized extract obtained by MAE was used as an active antioxidant in multilayer food packaging films. The multilayer low-density polyethylene (LDPE)/polyethylene terephthalate (PET) containing 10% of MAE optimized extract provided the most antioxidant power acting as a free radical scavenger.