Production and Physicochemical Characterization of Gelatin and Collagen Hydrolysates from Turbot Skin Waste Generated by Aquaculture Activities.

Rising trends in fish filleting are increasing the amount of processing by-products, such as skins of turbot, a flatfish of high commercial value. In line with circular economy principles, we propose the valorization of turbot skins through a two-step process: initial gelatin extraction described for the first time in turbot, followed by hydrolysis of the remaining solids to produce collagen hydrolysates. We assayed several methods for gelatin extraction, finding differences in gelatin properties depending on chemical treatment and temperature.

Optimal Recovery of Valuable Biomaterials, Chondroitin Sulfate and Bioapatites, from Central Skeleton Wastes of Blue Shark.

The industrial filleting of blue shark () led to the generation of a large number of central skeletons of low interest to fishmeal plants handling such wastes. In this context, the present study describes the optimization of the hydrolysis process (pH 8.35, T 58 °C, 1% () of alcalase and t = 4 h) to produce chondroitin sulfate (CS) together with the recovery of bioapatites.

Chondroitin sulfate and hydroxyapatite from Prionace glauca shark jaw: Physicochemical and structural characterization.

In the present work, the potential of the Prionace glauca jaw as a source of both chondroitin sulfate and bioapatite is explored. The sandwich-type structure in cross section of the jaw based on alternate layers with prevalence in organic tissue or mineralized is shown and these bands respectively confirmed as CS or hydroxyapatite -enriched zones. As result of this, an optimized process in sequential steps for the recovery of both biomaterials and their purification process is proposed, by combining enzymatic proteolysis, chemical precipitation and separation using ultrafiltration membrane for CS production together with controlled thermal treatment for hydroxyapatite obtaining.

Optimal isolation and characterisation of chondroitin sulfate from rabbit fish (Chimaera monstrosa).

Chondroitin sulfate (CS) is a glycosaminoglycan widely explored for cartilage regeneration. Its bioactivity is influenced by sulfation degree and pattern, and distinct sulfation in marine CS may open new therapeutic possibilities. In this context, we studied for the first time the isolation and characterisation of CS from Rabbit Fish (Chimaera monstrosa).

Valorization of recurrently discarded fish species in trawler fisheries in North-West Spain.

The progressive elimination of fish discards established by the European Union Council in 2013 has stimulated the valorization of flesh from discarded high-quality species with good protein functional properties but which frequently have excessive fish-bones, fat, strange flavours, soft texture, etc. The present study therefore focuses on valorization of the extracted muscle (minced muscle), from several fish species frequently discarded in north-western Spanish fisheries (Atlantic Ocean): Blue whiting (), Mackerel (), Red scorpionfish (), Pouting () and Gurnard ( spp.).