Optimization of the autolysis of rainbow trout viscera for amino acid release using response surface methodology.

Background: Due to the huge amounts of their production in Europe, their environmental impact, and the difficulty in processing them, there is a clear necessity for the valorization of rainbow trout viscera. Considering that the production of fishmeal with viscera can be problematic, and in order to make viscera more profitable, the production of fish protein hydrolysates has been considered. Although silage and enzymatic hydrolysis are the most common methods for obtaining hydrolysates, autolysis has emerged as an alternative method that uses endogenous enzymes of the viscera.

Comparison of amino acid release between enzymatic hydrolysis and acid autolysis of rainbow trout viscera.

Fish protein hydrolysates were obtained from cultured rainbow trout (Oncorhynchus mykiss) viscera using commercial and endogenous enzymes. Two methods were employed for hydrolysis: acid autolysis (also known as silage) at room temperature for 10 days in acidic conditions, until total solubilisation, and enzymatic hydrolysis using Alcalase 2.4 LFG, Protana Prime, and the endogenous enzymes in the viscera.

Determination of fluoroquinolones in fish tissues, biological fluids, and environmental waters by liquid chromatography tandem mass spectrometry.

This work describes the optimization, validation, and application in real samples of accurate and precise analytical methods to determine ten fluoroquinolones (FQs) (norfloxacin, enoxacin, pefloxacin, ofloxacin, levofloxacin, ciprofloxacin, danofloxacin, lomefloxacin, enrofloxacin, and sparfloxacin) in different environmental matrices, such as water (estuarine, seawater, and wastewater treatment plant effluent), fish tissues (muscle and liver), and fish biofluids (plasma and bile). The analysis step performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was fully optimized to improve the separation and detection steps. The extraction of analytes from fish tissues was accomplished using focused ultrasound solid-liquid extraction using methanol/acetic acid (95:5 v/v) as extractant.