Optimization of extraction of phenolic acids from a vegetable waste product using a pressurized liquid extractor

This study identified the phenolic acids in potato peels, tuber, and developed an optimized method for extraction of phenolic acids from potato peels using a pressurized liquid extractor (PLE). Caffeoylquinic acid isomers were the predominant phenolic acids present in potato peels as identified by HPLC and LC–MS analysis. The phenolic acids extracted from potato peels were over tenfold higher than that of the tubers. A variety of PLE parameters were investigated to optimize the extraction conditions. The results indicated that the optimum yields of phenolic acids from the potato peels were extracted with methanol/water (90:10, v/v) at 160 °C with a solid-to-solvent ratio of 250 mg with 20 mL of solvent using a pressurized liquid extractor. Although static time variations (5–15 min), pressure (500–2000 psi), and flush volume (10–100%) variations did not significantly improve the extraction yields of phenolic acids, optimization of the above three parameters will result in significant reduction of the resources used and waste generated, thereby impacting the overall operation cost. The results presented in this manuscript suggest that optimization of extraction parameters is critical for accurate quantification of phytochemicals present in foods and other plant based products.

► Optimization of extraction of phenolic acids from potato peels.
► Caffeoylquinic acid isomers were the predominant phenolic acids present in peels.
► Highest yields of phenolic acids were obtained with methanol/water (90:10, v/v).
► Temperature, particle size, and solid-to-solvent ratio also impacted extraction yield.
► Pressure, static time, and flush volume did influence extraction yields.