Jose Luis  Hoyos-Concha, Hector Samuel  Villada-Castillo, Alejandro  Fernández-Quintero, Rodrigo  Ortega-Toro, 
    Physicochemical and Microbiological Characterization of an Endogenous Enzymatic
Hydrolysate Obtained by Adding Formic Acid to Trout Viscera (<i>Oncorynchus mykiss</i>),
    Journal of Engineering and Applied Sciences,
    Volume 15,Issue 14,
    2020,
    Pages 2811-2816,
    ISSN 1816-949x,
    jeasci.2020.2811.2816,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2020.2811.2816)
    Abstract: By-products obtained in the development of
fish farming such as trout entrails have a high protein and
oil content in their composition with potential use in the
food agribusiness. There are alternative methods such as
chemical silage which facilitates fat extraction and
obtaining of hydrolysed protein due to the action of
endogenous proteases which are activated in an acidic
medium during this process. The main objective of this
work was to obtain and characterise physicochemical and
microbiologically a hydrolysed protein meal from trout
by-products (<i>Oncorhynchus mykiss</i>). Proximal analysis
(humidity, ash, ethereal extract and crude protein) and
microbiological analysis were performed to finally
obtain an endogenous hydrolysate to which the degree of
hydrolysis, pH, titratable acidity and oil yield was
determined. It was found that the treatment carried out
using chemical silage generates an acidic environment
(pH 3.2) that prevents microbial decomposition and
facilitates the extraction of the lipid fraction. The
hydrolysis process obtained, close to 62%, allows
obtaining a product called hydrolysed protein meal that
according to its composition could be used to formulate
farm animal&#146;s diet.
    Keywords: Oncorhynchus mykiss;viscera;chemical silage;hydrolysis;trout