Enhanced Phenolics Extraction from Mangosteen Pericarps Using Pulsed Electric Field-Microwave Assisted Technique Xukai Saw (1), Angky Wahyu Putranto (1,2) and Gek Cheng Ngoh (1)*
1. Sustainable Process Engineering Centre (SPEC), Department of Chemical Engineering, Faculty of Engineering, Universiti Malaya, 50603, WP Kuala Lumpur, Malaysia
2. Department of Biosystems Engineering, Faculty of Agricultural Technology, Universitas Brawijaya, 65145, East Java, Indonesia
* Corresponding email: ngoh[at]um.edu.my
Abstract
Extraction of phenolic compounds from mangosteen pericarps has been gaining interest due to the potential health benefits associated with their antioxidant, antiinflammatory and anti-cancer properties. This study explores a novel technique by combining pulsed electric field (PEF) and microwave-assisted extraction (MAE) sequentially to enhance phenolics extraction from mangosteen pericarps. Besides, limitations of conventional extraction techniques such as long extraction time, low extraction yield, and large consumption of harmful solvents can also be overcome. The innovative PEF-MAE approach, incorporated with green deep eutectic solvent (DES), leverages PEF to disrupt cell membranes, leading to increased tissue permeability while facilitating the release of phenolics during the subsequent MAE process. Key parameters such as electric field strength, pulse duration, irradiation power and irradiation duration were optimized to maximise phenolic yield. Based on the analysis of the optimization results using response surface methodology (RSM), the optimal extraction conditions using MAE with choline chloride/ethylene glycol (ChCl-EG) as solvent were 424.23 W and 1.76 mins, achieving the highest TPC content of 87.41 mg GAE/g dw. The optimized MAE conditions were then coupled with the optimized PEF conditions (4.99 kV/cm, 2.72 mins) obtained for sequential phenolics extraction. The results demonstrate a significant improvement in extraction yield, with PEF-MAE method achieving a 22.28% increase in TPC and 106.93 mg GAE/g dw as compared to that using sole MAE. Although a 22.24% higher in energy consumption using PEF-MAE, the significant increment in extracted phenolics might offset the operational cost incurred from higher energy usage, further suggesting that the PEF-MAE technique is promising and scalable for industrial applications. More importantly, this combined technique offers an effective solution for extracting valuable phenolic compounds from Mangosteen pericarp
Keywords: Deep eutectic solvents pretreatment- Mangosteen pericarps- Microwave-assisted extraction- Phenolic compounds- Pulsed electric field
