Microwave-assisted extraction of antioxidant compounds from by-products of Turkish hazelnut (Corylus avellana L.) using natural deep eutectic solvents: Modeling, optimization and phenolic characterization

• Published in: Food chemistry 2022-08, Vol.385, p.132633-132633, Article 132633
• Main Authors: Bener, Mustafa, Şen, Furkan Burak, Önem, Ayşe Nur, Bekdeşer, Burcu, Çelik, Saliha Esin, Lalikoglu, Melisa, Aşçı, Yavuz Selim, Capanoglu, Esra, Apak, Reşat
• Format: Article
• Language: English
• Subjects: Antioxidants - chemistry; Antioxidants recovery; Corylus - chemistry; Deep Eutectic Solvents; Hazelnut pomace; Industrial waste valorization; Microwave-assisted extraction; Microwaves; Natural deep eutectic solvents; Phenols - chemistry; Plant Extracts - chemistry; Solvents - chemistry; Tandem Mass Spectrometry
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2022.132633

[Display omitted] •A green method developed for antioxidants extraction from hazelnut by-products.•Natural deep eutectic solvents (NADES) were combined to obtain optimal extraction.•Choline chloride:1,2-propylene glycol was chosen as the most suitable NADES.•Microwave-assisted extraction (MAE) was modelled and optimized for antioxidants.•Phenolic composition of hazelnut extracts screened by UPLC-PDA-ESI-MS/MS. An environmentally friendly method using natural deep eutectic solvents (NADES) and microwave-assisted extraction (MAE) for the recovery of bioactive compounds from hazelnut pomace (a hazelnut oil process by-product) was developed to contribute to their sustainable valorization. Eight different NADES were prepared for the extraction of antioxidant constituents from hazelnut pomace, and choline chloride:1,2-propylene glycol (CC-PG) was determined as the most suitable NADES, considering their extraction efficiency and physicochemical properties. After selecting suitable NADES, operational parameters for the MAE process of antioxidants from hazelnut pomace were optimized and modeled using response surface methodology. For the highest recovery of antioxidants, the operational parameters of the MAE process were found to be 24% water, 38 min, 92 °C and 18 mL/0.1 g-DS. Under optimized conditions, extracts of both pomace as a by-product and unprocessed hazelnut flours of three different hazelnut samples (Tombul, Çakıldak, and Palaz) were prepared, and their antioxidant capacities were evaluated by spectrophotometric methods. Antioxidant capacities of CC-PG extracts of all hazelnut samples were 2–3 times higher than those of ethanolic extracts. In addition, phenolic characterization of the prepared extracts was carried out using the UPLC-PDA-ESI-MS/MS system. The results of this study suggest that hazelnut by-products can potentially be considered an important and readily available source of natural antioxidants. Furthermore, the modeled MAE procedure has the potential to create an effective and sustainable alternative for pharmaceutical and food industries.