Combined Pulsed Electric Field and Microwave-Assisted Extraction as a Green Method for the Recovery of Antioxidant Compounds with Electroactive Potential from Coffee Agro-Waste

Abstract

Coffee agro-waste is a potential source of polyphenols with antioxidant activity and application in the food and cosmetic trades. The usage of these byproducts persists as a challenge in the industrial landscape due to their high content of purported toxic substances hindering management. This study presents a green extractive process using pulsed electric field (PEF) and microwave assisted extraction (MAE) to recover polyphenols from coffee parchment and two varieties of pulp, posing quick processing times and the use of water as the only solvent. The performance of this process with regard to the bioactivity was assessed through the Folin-Ciocalteu assay, total flavonoid content, DPPH, ABTS and FRAP antioxidant tests. The phenolic composition of the extracts was also determined through HPLC-MS and quantified through HPLC-DAD. When compared to treatment controls, PEF + MAE treated samples presented enhanced yields of total phenolic content and radical scavenging activity in all analyzed residues (Tukey test significance: 95%). The chromatographic studies reveal the presence of caffeic acid on the three analyzed by-products. The HPLC-DAD caffeic acid quantification validated that a combination of MAE + PEF treatment in yellow coffee pulp had the highest caffeic acid concentration of all studied extraction methods.

Exploiting residual cocoa biomass to extract advanced materials as building blocks for manufacturing nanoparticles aimed at alleviating formation-induced oxidative stress on human dermal fibroblasts

“…The TPC of the extracts was determined using the Folin–Ciocalteu method. 18 Briefly, 10 mg of dry pectin were suspended in 1 mL of dH 2 O, and then 50 μL of the resulting extracts were mixed with 430 μL of dH 2 O and 20 μL of the Folin–Ciocalteu reagent. After stirring, a 20% w/v Na 2 CO 3 solution was added and allowed to stand for 10 min.…”

Pulsed Electric Field Applications for the Extraction of Bioactive Compounds from Food Waste and By-Products: A Critical Review

“…Macías-Garbett et al [123] developed a green extractive technique that employs PEF pretreatment and MAE to extract bioactive compounds (polyphenols) from coffee parchment and two types of pulp (yellow and red pulp), with short processing times and water as the single solvent. The pretreatment operating parameters were established at a total treatment time of 5 min, electric field strength of 6 kV/cm, and pulse frequency of 5 Hz.…”

Biorefinery and Stepwise Strategies for Valorizing Coffee By-Products as Bioactive Food Ingredients and Nutraceuticals

“…Current methods, such as solvent extraction and enzymatic hydrolysis, have limitations in terms of efficiency, sustainability, and cost-effectiveness [261]. Novel methods such as microwave-assisted extraction, supercritical fluid extraction, and pulsed electric field extraction show potential for improving the production of bioactive compounds from coffee by-products [262][263][264]. Other potential research areas include the use of enzymatic hydrolysis and fermentation to produce novel functional food ingredients and nutraceuticals [265,266].…”