Subcritical Water Extraction and Hydrolysis of Cod (Gadus morhua) Frames to Produce Bioactive Protein Extracts

Abstract

The valorization of Atlantic cod (Gadus morhua) frames from a filleting industry was investigated using subcritical water extraction and hydrolysis (SBW) at different temperatures (90, 140, 190 and 250 °C) and 100 bar to obtain extracts rich in proteins, peptides and amino acids. Up to 57.7 g of extract per 100 g of codfish frames were obtained, with nearly total recovery of the protein fraction. At each temperature, protein extracts of decreasing molecular weight were obtained, according to SEC-GPC results. Most of the protein present in the raw material and extracts was collagen and collagen fragments, as suggested by the amino acid profile. Codfish SBW extracts did not show cytotoxicity in the range of concentrations tested and the protein extract obtained at the lowest temperature (90 °C) showed the highest anti-inflammatory potential in human intestinal epithelium cell model. The mineralized residue left after SBW treatment of cod frames was identified as practically pure, crystalline, hydroxyapatite, that may find applications in biomedical field and hard-tissue engineering. This study shows the possible valorization of cod frames using green extraction methods such as SBW process to obtain protein extracts for food and nutraceutical applications.

Steam Explosion-Assisted Extraction of Protein from Fish Backbones and Effect of Enzymatic Hydrolysis on the Extracts

“…The modification of protein structure, through innovative pretreatment prior to enzymatic hydrolysis, is a good strategy to enhance the hydrolysate properties [15]. Recently, the ability of hydrothermal processing (about 120-250 • C), such as hot-pressure extraction [14] and subcritical water hydrolysis [16], in the hydrolysis of bio-macromolecules, has been explored. Under hydrothermal conditions, the ionic product of water is increased, through the formation of hydronium and hydroxide ions, making water or steam appear as an acid or base catalyst [17].…”

“…Under hydrothermal conditions, the ionic product of water is increased, through the formation of hydronium and hydroxide ions, making water or steam appear as an acid or base catalyst [17]. In recent years, hydrothermal pretreatment, with or without enzymatic hydrolysis, has been used to extract protein and produce protein hydrolysates or free amino acids from different protein sources, including chicken bone [14], porcine skin [18], and fish byproducts [16,[19][20][21][22].…”

Conventional use and sustainable valorization of spent egg-laying hens as functional foods and biomaterials: A review

“…Besides, spent hen is rich in collagen with high crosslinking degree (Hong et al 2019 ). Hence, new methods, such as hydrothermal processing and subcritical water hydrolysis, should be explored to break down the highly crosslinked collagen before being developed for food and cosmetic uses (Adams et al 2018 ; Dong et al 2014 ; Melgosa et al 2021 ).…”

Bioactive Peptides from Algae: Traditional and Novel Generation Strategies, Structure-Function Relationships, and Bioinformatics as Predictive Tools for Bioactivity

“…Amongst them, subcritical water (SCW) processing has been gaining attention as both a green extraction and protein hydrolysis method [ 50 , 51 , 52 ]. SCW does not require the use of expensive and lengthy reaction times and it can be a method of extracting compounds from highly insoluble media which are ecologically damaging by-products from industries, such as poultry waste [ 53 ], hog fur [ 54 ] and fisheries waste [ 55 ]. In fact, SCW production of bioactive peptides also significantly reduces the processing time of hydrolysis of collagen by a factor of almost 300 when using enzymatic methods such as collagenase [ 56 ] to up 5 min [ 57 ].…”