Successive extraction using natural deep eutectic solvents and pressurized liquids for a greener and holistic recovery of proteins from pomegranate seeds. (November 2022)

• Record Type: Journal Article
• Authors: Guzmán-Lorite, M.; Marina, M.L.; García, M.C.
• Is Part Of: Food research international. Volume 161(2022)
• Publication Date: 2022-11
• Subjects: Sequential extraction -- Food waste -- Antioxidant activity -- Mass spectrometry -- Peptides -- Phenolic compounds; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2022.111862
• Languages: English
• ISSNs: 0963-9969

Abstract

Graphical abstract: Highlights: Natural deep eutectic solvents are suitable and green alternatives for extracting proteins. No single extraction guarantees the total extraction of proteins with different characteristics. Successive extraction by NADES and PLE allowed to recover 44% more protein than NADES alone. Proteins extracted with NADES were larger, more hydrophobic, more soluble at acidic pH than PLE. Unlike PLE, NADES mostly extracted storage proteins. Abstract: This work describes a novel and sustainable strategy for the recovery of proteins by successive extractions using natural deep eutectic solvents (NADES) and pressurized liquid extraction (PLE). This strategy was applied to the valorisation of pomegranate seeds. Nine different NADES were screened and that constituted by choline chloride and acetic acid was chosen due to its best performance. A Response Surface Methodology was employed to optimize other conditions in this extraction step: time, temperature, amount of sample, and HIFU amplitude. Protein recovery, under optimal conditions, was 13.3 g of proteins/100 g of milled and dried defatted seeds. Proteins were next characterized by their separation using RP-HPLC, SDS-PAGE, isoelectrofocusing electrophoresis, and by the evaluation of their digestibility and antioxidant properties. Comparison of these results with those from extracts obtained by other techniques supported the interest of combining the extraction using acid NADES with PLE, under alkaline conditions. The successive extraction by both methodologies enabled to double the total recovery of proteins. The analysis of samples by UHPLC-MS/MS, after a simulated gastrointestinal digestion, and de novo identification revealed the presence of 19 peptides in the NADES hydrolysate, while the successive extraction by PLE enabled to observe 15 additional peptides. Additional 83 peptides were found by database searching against Punica granatum and by homology with other organisms. Differences between peptides and the proteins in both hydrolysates confirmed the different protein selectivity of both strategies and the potential of NADES for extracting larger proteins and PLE for the extraction of smaller ones. Some phenolic compounds, amino acids, and fatty acids were also co-extracted with proteins in both extractions.