Accelerated Solvent Extraction and Pulsed Electric Fields for Valorization of Rainbow Trout (Oncorhynchus mykiss) and Sole (Dover sole) By-Products: Protein Content, Molecular Weight Distribution and Antioxidant Potential of the Extracts

Abstract

Fishery by-products are rich in biologically active substances and the use of green and efficient extraction methods to recover these high-added-value compounds is of particular importance. In this study, head, skin and viscera of rainbow trout and sole were used as the target matrices and accelerated solvent extraction (ASE) (45–55 °C, 15 min, pH 5.2–6.8, 103.4 bars) and pulsed electric fields (PEF) (1–3 kV/cm, 123–300 kJ/kg, 15–24 h) were applied as extraction technologies. The results showed that ASE and PEF significantly increased the protein extract efficiency of the fish by-products (p < 0.05) by up to 80%. SDS-PAGE results showed that ASE and PEF treatments changed the molecular size distribution of the protein in the extracts, which was specifically expressed as the change in the area or number of bands between 5 and 250 kDa. The antioxidant capacity of the extracts was evaluated by oxygen radical absorbance capacity (ORAC) and total antioxidant capacity (ABTS) assays. The results showed that both ASE and PEF treatments significantly increased the antioxidant capacity of rainbow trout and sole skin and head extracts (p < 0.05). ASE and PEF extraction processes can be used as new technologies to extract high-added-value compounds from fish by-products.

Role of Extracts Obtained from Rainbow Trout and Sole Side Streams by Accelerated Solvent Extraction and Pulsed Electric Fields on Modulating Bacterial and Anti-Inflammatory Activities

“…Two different methods have shown different effects on the antioxidant capacity of the extracts. Previously, the antioxidant capacity of the extracts without sterile membrane filtration was also measured [19]. Comparing the results before and after filtration, it was found that filtration had relatively little effect on the antioxidant capacity of the extracts, meaning the nutrients and antioxidant compounds in the extracts were well retained, which provides a basis for further experiments.…”

“…Therefore, in the present work based on a previous study [19], the fish side streams of two fish species (rainbow trout and sole) with high nutritional values were selected as the target matrices to recover high-value-added compounds with potential antioxidant, antimicrobial and prebiotic activities. For this purpose, PEF and ASE were used to recover the bioactive compounds from fish side streams (head, skin and viscera), then the protein content and the total antioxidant capacity of the recovered compounds were evaluated.…”

Salmon (Salmo salar) Side Streams as a Bioresource to Obtain Potential Antioxidant Peptides after Applying Pressurized Liquid Extraction (PLE)

“…The possibility of applying different extraction conditions has made PLE a useful tool to optimize the extraction of high-added-value compounds from a wide variety of matrices, including marine sources and related side streams. For instance, PLE-assisted extraction was recently used to obtain aqueous protein extracts with in vitro antioxidant capacity from several side streams of rainbow trout, sole, sea bass, and sea bream [17][18][19]. Protein extraction from macro-and micro-algae using PLE has been also investigated [20].…”

Impact of Pressurized Liquid Extraction and pH on Protein Yield, Changes in Molecular Size Distribution and Antioxidant Compounds Recovery from Spirulina

“…The former is to examine the ability of the sample to scavenge ROO, OH and other free radicals, and the latter is to examine the ability of the sample to scavenge ABTS+ free radicals. Since the type of free radicals removed by the samples are different, the results are also inconsistent [ 32 ], although differences between the two assays, such as the corresponding end point times, could also explain the results observed. Spirulina has been extensively studied due to its great content of various functional compounds.…”