Evaluation of Process Parameters on Phenolic Recovery and Antioxidant Activity Using Ultrasonic and Microwave-Assisted Extraction from Pineapple Peel

Abstract

This study investigated the influence of process parameters on the recovery of phenolic compounds and antioxidant activity from pineapple peel using green extraction technologies: ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE). A two-level factorial design was used to evaluate the effects of the solvent-to-solid ratio, time, temperature, ethanol concentration, and power on the yield of hydrolyzable and condensed polyphenols. The extracts were characterized using HPLC-MS, and their antioxidant activity was assessed using DPPH, ABTS, and FRAP assays. UAE yielded the highest condensed polyphenol content (323.82 mg/g), while MAE extracts demonstrated superior antioxidant activity (FRAP: 90.40 mgEqTrolox/g). The predominant compound identified using both methods was 1-caffeoylquinic acid. The most influential variable in UAE was the solvent-to-solid ratio, whereas extraction time was the most significant variable in MAE. These findings highlight the potential of pineapple peel valorization through sustainable extraction methods, with UAE favoring phenolic yield and MAE enhancing bioactivity, thereby supporting their application in the food and nutraceutical industries.