Optimization of polyphenol recovery from potato peel and its incorporation into low-density polyethylene films activated by cold plasma

The optimal conditions for polyphenol extraction from potato peel using conventional solvent extraction (CSE) and ultrasound-assisted extraction (UAE) methods were predicted to estimate the highest amounts of polyphenols by exploiting a response surface methodology (RSM). The effects of several independent variables, including extraction time, type, and concentration of solvents, on responses (yield, phenolic, flavonoid, and antioxidant activity) were investigated. In the next stage, the potato peel extract (PPE) was incorporated into the low-density polyethylene (LDPE) using plasma treatment to produce an active polymeric film containing natural antioxidants. Polynomial models were significantly fitted to the experimental data based on the Design-Expert software. The highest amounts of responses including yield (9.54%), total phenolic content (TPC) (969.22 mg GAE/100 g dried weight (DW)), total flavonoid content (TFC) (266.53 mg QE/100 g DW), and DPPH (92.36%) in the UAE method, and yield (8.88%), TPC (701.73 mg GAE/100 g DW), TFC (167.4 mg QE/100 g DW), and DPPH (72.28%) in the CSE method were achieved under optimal conditions. Overall, a good agreement between predicted and experimental values was observed under optimal conditions. Besides, the ATR-FTIR results showed the proper attachment of polyphenol compounds on the LDPE using plasma treatment. Graphical Abstract