Recovery of phenolic compounds from peach pomace using conventional solvent extraction and different emerging techniques.

Abstract

The study compared high-pressure, microwave, ultrasonic, and traditional extraction techniques. The following extraction conditions were implemented: microwave-assisted extraction (MAE) at 900W power for durations of 30, 60, and 90s; ultrasonic-assisted extraction (UAE) at 100% amplitude for periods of 5, 10, and 15min; and high-pressure processing (HPP) at pressures of 400 and 500MPa for durations of 1, 5, and 10min. The highest yield in terms of total phenolic content (PC) was obtained in UAE with a value of 45.13±1.09mg gallic acid equivalent (GAE)/100g fresh weight (FW). The highest PC content was determined using HPP-500MPa for 10min, resulting in 40mg GAE/100g, and MAE for 90s, yielding 34.40mg GAE/100g FW. The highest value of antioxidant activity (AA) was obtained by UAE in 51.9%±0.71%. The PCs were identified through the utilization of Fourier transform infrared (FTIR) spectroscopy and high-performance liquid chromatography (HPLC). Utilizing multivariate analysis, the construction of chemometric models were executed to predict AA or total PC of the extracts, leveraging the information from IR spectra. The FTIR spectrum revealed bands associated with apigenin, and the application of HPP resulted in concentrations of 5.41±0.25mg/100g FW for apigenin and 1.30±0.15mg/100g FW for protocatechuic acid. Furthermore, HPLC analysis detected the presence of protocatechuic acid, caffeic acid, p-coumaric acid, and apigenin in both green extraction methods and the classical method. Apigenin emerged as the predominant phenolic compound in peach extracts. The highest concentrations of apigenin, p-coumaric acid, and protocatechuic acid were observed under HPP treatment, measuring 5.41±0.25, 0.21±0.04, and 1.30±0.15mg/kg FW, respectively.