Supercritical fluid extraction for enhancing polyphenolic compounds production from olive waste extracts

Abstract

BACKGROUNDA number of residues are produced during the olive oil extraction process, such as crushed pits, olive leaves, pomace and exhaust olive pomace. In addition, pruning of olive trees results in a huge amount of biomass. All of these lignocellulosic materials constitute a source of energy and chemicals that can be used as raw materials in biorefineries. Among them, antioxidants are of particular interest due to their potential applications in pharmaceutical and food industry.RESULTSSupercritical fluid extraction (SFE) was applied on three different olive residues – pruning biomass, leaves and exhaust pomace. In this, 60% ethanol was used as cosolvent at three different pressure levels, 200, 250 and 300 bar. The best conditions for each residue were determined and compared with conventional extraction. Results show that 300 bar was the best pressure for SFE in terms of antioxidant activity of the extracts. The main polyphenolic compounds also were identified, among which hydroxytyrosol, chlorogenic acid, caffeic acid and ferulic acid were present.CONCLUSIONSFE at 300 bar proved to be the best option for obtaining a high‐activity antioxidant extract from olive leaves, exhaust pomace and pruning biomass, with hydroxytyrosol the prominent compound detected. This procedure could be integrated in a biorefinery based on olive‐derived biomass. © 2018 Society of Chemical Industry

Valorisation of Exhausted Olive Pomace by an Eco-Friendly Solvent Extraction Process of Natural Antioxidants

“…Recovery of antioxidant phenols from olive pomace has been performed using common organic solvents such as ethanol [ 11 ] or methanol [ 12 ] in an agitated reactor under high pressure and temperature. Olive pomace has also been hydrothermally pretreated by steam explosion [ 13 ] and subcritical fluid extraction [ 14 , 15 ]. New extraction technologies for olive pomace, such as microwave-assisted extraction, ultrasound-assisted extraction with different solvents [ 16 , 17 , 18 , 19 ], and extraction with natural deep eutectic solvents [ 16 ] have also been reported.…”

Supercritical CO2 Extraction of Phytocompounds from Olive Pomace Subjected to Different Drying Methods

“…Various studies have been reported on supercritical fluid extraction with or without a cosolvent of phytosterols, essential oils, pigments [ 29 ], and mainly polyphenols from blueberry, cranberry, and raspberry wastes [ 30 ]; wine industry by-products [ 31 ]; pistachio hull [ 32 ]; olive leaves [ 33 ]; and orange, apple, and tomato pomace [ 34 , 35 , 36 , 37 ]. The SFE of polyphenols has been further carried out from olive pomace [ 38 ].…”

Low-Molecular-Weight Phenols Recovery by Eco-Friendly Extraction from Quercus Spp. Wastes: An Analytical and Biomass-Sustainability Evaluation

“…Phenolic compounds such as gallic acid, catechin, and epicatechin are notoriously endowed with antioxidants, astringents, and antimicrobial activity. Therefore, such species are subject of increasing interest in various fields such as pharmaceuticals, leather tanning, cosmetics, and the food industry [7][8][9][10][11]. Low-molecular-weight hydroxybenzoic acids and some of their derivatives can be obtained from wood extractives and via induced lignin degradation [12,13].…”