Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2011
Publication Date: 2/1/2012
Publication URL: http://handle.nal.usda.gov/10113/55587
Citation: Wu, T.H., Bechtel, P.J. 2012. Screening for low molecular weight compounds in fish meal solubles by hydrophilic interaction liquid chromatography coupled to mass spectrometry. Food Chemistry. 130(3):739-745. Interpretive Summary: Small soluble compounds generated in the water fraction (stickwater) from processing fish meal are potentially beneficial as specialized feed ingredients. A technique was developed to screen the water fraction for these small soluble compounds. The method required little prep work of the sample and multiple classes of compounds could be eventually identified. The method was applied to non-treated and enzyme treated pollock stickwater and five major small soluble compounds were identified and quantified. Concentrations of the five compounds were significantly different between the non-treated and enzyme treated pollock stickwater.
Technical Abstract: A simple analytical method using hydrophilic interaction liquid chromatography coupled with mass spectrometry was developed to screen for low molecular weight compounds in enzyme treated and untreated Alaskan pollock (Theragra chalcogramma) stickwater (SW) generated from processing fish meal with pollock byproduct. Sample preparation was quick and involved ultracentrifugation (cut off < 3000 g/mol) of reconstituted freeze dried samples for direct analysis on mass spectrum (MS). Full MS scan (50-2000 g/mol) in dual detection mode (atmospheric pressure chemical and electrospray ionization) resulted in the identification of 5 abundant compounds (creatine, creatinine, inosine, trimethylamine and trimethylamine oxide (TMAO)) and quantification was performed with selective ion monitoring based on calibration standards. The major low molecular weight compound detected in untreated SW was TMAO at 25.2±2.08 mg/g dry weight (dw) and in enzyme-treated SW was creatine at 10.5±0.47 mg/g dw.