Abstract
The expansion of fish filleting, driven by the increasing demand for convenience food, concomitantly generates a rising amount of skinning by-products. Current trends point to a growing share of aquaculture in fish production, so we have chosen three established aquaculture species to study the properties of gelatin extracted from their skin: rainbow trout, commonly filleted; and seabass and seabream, marketed whole until very recently. In the first case, trout skin yields only 1.6% gelatin accompanied by the lowest gel strength (96 g bloom), while yield for the other two species exceeds 6%, and gel strength reaches 181 and 229 g bloom for seabass and seabream, respectively. These results are in line with the proportion of total imino acids analyzed in the gelatin samples. Molecular weight profiling shows similarities among gelatins, but seabass and seabream gelatins appear more structured, with higher proportion of β-chains and high molecular weight aggregates, which may influence the rheological properties observed. These results present skin by-products of seabream, and to a minor extent seabass, as suitable raw materials to produce gelatin through valorization processes.
Highlights
Fish consumption has risen steadily in the last decades, accompanied by an increasing share of aquaculture production at the expense of wild capture [1]
To the best of our knowledge, no studies have explored the recovery of gelatin from the skin waste of seabream and European seabass, and research on rainbow trout is quite limited
In the present work we study the process of gelatin extraction and determine the physicochemical properties of the gelatins obtained from these species
Summary
Fish consumption has risen steadily in the last decades, accompanied by an increasing share of aquaculture production at the expense of wild capture [1]. Skin by-products from filleting new species may represent a good source of gelatin not previously described because of lack of availability of the raw material With this view, we have selected two species marketed whole until very recently, seabass (Dicentrarchus labrax) and seabream (Sparus aurata); and the long-established rainbow trout (Oncorhynchus mykiss). Estimations of absolute molecular weight by gel permeation chromatography with light scattering detection, performed for the first time in these materials, allow to relate the physical properties of the gels with gelatin structure This represents fundamental information for the design of valorization processes to recover gelatin from skin waste of the studied species
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