Utilization of by-products from the salmon industry: The chemical composition and storage stability of Atlantic salmon (Salmo salar) heads

• Main Author: Zhihao Liu 1995-
• Other Authors: Háskóli Íslands
• Format: Thesis
• Language: English
• Published: 2019
• Subjects: Matvælafræði; Laxeldi; Hráefni; Efnasamsetning; Geymsluþol; Ísland; Salmon farming; Raw materials; Chemical composition; Storage; Atlantic salmon; Iceland; Salmo salar
• Online Access: http://hdl.handle.net/1946/34468

Previous studies have indicated the current situation and the need of utilizing by-products from the salmon industry. Awareness of the potential values behind these by-products is rising, but most of the by-products ended up in low-value silage for animal feeding or simply wasted. The main goal of this project is to investigate the possible utilization of heads from locally farmed Atlantic salmon (Salmo salar) in Iceland. Obtaining knowledge of the physiochemical properties of the different parts from salmon heads and their quality and stability as affected by frozen storage conditions are a prerequisite for further value-adding. There were three major parts of this project. The first part was to determine the yield, content of water, protein, ash, lipid, fatty acid, free fatty acid, phospholipid, peroxide, thiobarbituric acid reactive substances in brain, tongue, eyes, pectoral fins, and gills. The second part was to trace these contents for those five parts individually every two months from October 17th, 2018 to February 26th, 2019. The third part was an attempt to extract collagen from 5 whole salmon heads. The contents of water, lipid, protein and ash had wide ranges among the five analyzed parts and water, protein and ash were stable for all five parts during the 4-month storage at -25°C. Brain, tongue and eyes showed high amount of lipid, and tongue and eyes could be interesting sources for lipid extraction considering the size and removability. Bony tissues like tongue, fins and gills contained more protein and ash than soft tissues like brain and eyes. And gills possessed large varieties of interesting minerals like zinc and calcium, and the content of calcium was high. Fins were very prone to lipid oxidation and the major part of primary oxidation was finished already before the samples were sent to Matís. Gills and eyes also had high level of both primary and secondary oxidation during the 4-month storage. Collagen extracted from whole salmon head was slightly yellowish and had a relatively satisfying ...