Production of Valuable Compounds and Bioactive Metabolites from By-Products of Fish Discards Using Chemical Processing, Enzymatic Hydrolysis, and Bacterial Fermentation

Abstract

The objective of this report was to investigate the isolation and recovery of different biocompounds and bioproducts from wastes (skins and heads) that were obtained from five species discarded by fishing fleets (megrim, hake, boarfish, grenadier, and Atlantic horse mackerel). Based on chemical treatments, enzymatic hydrolysis, and bacterial fermentation, we have isolated and produced gelatinous solutions, oils that are rich in omega-3, fish protein hydrolysates (FPHs) with antioxidant and antihypertensive activities, and peptones. FPHs showed degrees of hydrolysis higher than 13%, with soluble protein concentrations greater than 27 g/L and in vitro digestibilities superior to 90%. Additionally, amino acids compositions were always valuable and bioactivities were, in some cases, remarkable. Peptones that were obtained from FPHs of skin and the heads were demonstrated to be a viable alternative to expensive commercial ones indicated for the production of biomass, lactic acid, and pediocin SA-1 from Pediococcus acidilactici.

Valorization of Aquaculture By-Products of Salmonids to Produce Enzymatic Hydrolysates: Process Optimization, Chemical Characterization and Evaluation of Bioactives

“…The values of V dig were significantly superior in H than TF (p < 0.05). The levels reported here were in agreement with those observed in the production of hydrolysates of fish discards [10,27]. Depending on the method used for the quantification of proteins, the levels of protein material present in farmed FPHs ranged 48-69 g/L, 53-71 g/L, and 52-73 g/L for Prs, Pr-tN, and Pr (Σaa), respectively.…”

“…These results are lower than the amount of bones recovered from heads of different fish discards (red scorpionfish, blue whiting, mackerel, megrim, boardfish, etc.) after enzymatic digestion [10,27]. Besides, the recovered bones did not present a significant amount of residual muscle or organic material.…”

“…Enzymatic hydrolysis of fish wastes involves a highly controllable and reproducible method for the separation of bones, oils, and peptide fractions from complex matrices. Several fish species, including from farm origin, employing different proteases and conditions of hydrolysis have been studied in the last two decades [2,[8][9][10]. The functional capacity of FPHs in terms of antihypertensive, antioxidant, antiproliferative, antimicrobial, etc., in vitro bioactivities, is one of the most valuable properties of these bioproduction [11][12][13][14].…”

Utilization of marine by-products for the recovery of value-added products

“…Sometimes by-catch fish are kept for the market, but most often they are thrown back dead, because they may be the wrong species, the wrong size, of inferior quality, or surplus to the fishing operations quotas (UNEP 2004). However, according to the Landing Obligation of the European Commission Common Fisheries Policy, from 2019 onwards all fishing vessels are forced to keep all species that are caught without discarding, even though they are underutilized in commercial level (Vázquez et al, 2019). However, fish that are saleable vary considerably from country to country.…”

Characterization of the Jumbo Squid (Dosidicus gigas) Skin By-Product by Shotgun Proteomics and Protein-Based Bioinformatics

“…For this reason, valorization solutions of marine discards biomasses have to be implemented. These new potential bioactive compounds could be used for human nutrition, as well as for their functional properties for nutraceutical, pharmaceutical, and cosmeceuticals industries [4][5][6][7].…”