Comparison of oil yield and quality obtained by different extraction procedures from salmon (Salmo salar) processing byproducts

Abstract

The content and composition of lipids in different byproducts (skins, heads, and backbones) from mechanically processed farmed Atlantic salmon were determined and compared with that obtained from wild salmon. Three different procedures were used to establish the optimal conditions of oil extraction (at high temperature −95°C, “cold” extraction at temperature not exceeding 15°C and enzyme assisted with Alcalase). “Cold” extraction at temperature not exceeding 15°C was very efficient, yielding almost 95% of the oil from skins. In the case of heads the obtained yield of about 71% was not lower than that from extraction performed at 95 °C or extraction supported by enzyme treatment. The peroxide value of oil isolated from the heads using “cold” extraction was at the same level as in oil of the enzyme assisted process, but four times lower than in oil extracted at high temperature. The results showed that the content of lipids from in the farmed salmon byproducts the content of lipids was about 45–55% higher than in byproducts of wild salmon, however the EPA + DHA content was 10–33% lower. Practical applications: With “cold” extraction heating which is commonly used for oil recovery in the fish industry could be eliminated and thus the cost of the process would be lower and oxidative changes in the oil reduced. Furthermore, this method based on rules of “green chemistry” can be more attractive and alternative procedure of oil isolation from fatty fish byproducts than those using organic solvents. The fatty fish byproducts such as heads, skins, and backbones may be used as a source of valuable oils rich in PUFA. The remaining material after oil isolation can be a source of collagen and gelatin used in the food, pharmaceutical, and cosmetic industries and finally of minerals preparation (in the case of heads and backbones) used for enriching animal feed. The oil was extracted from salmon byproducts: heads, backbones, and skins by using different methods. Conventional extraction of the oil at high temperatures ensures high yield but leads to low quality of the product. Enzymatic extraction is more preserving to oils rich in polyunsaturated fatty acids, but has special requirements. An attractive solution can be the “cold” extraction. This procedure allows achieving the oil from fatty fish byproducts with high yield and quality in a simple and cheap way.

Optimisation of Healthy-Lipid Content and Oxidative Stability during Oil Extraction from Squid (Illex argentinus) Viscera by Green Processing

“…Additionally, comparison with traditional chemical extraction showed an oil yield around 64% as the highest value. High oil yields were obtained by Głowacz-Rozynska et al [15] when extracting different by-products (skin, head, and backbone) by three different non-solvent methods (high temperature, 95 • C; low temperature, <15 • C; enzyme-assisted procedure). Thus, oil yields were included in the 71-95% range when compared with traditional extraction.…”

“…However, the drastic temperature and pressure conditions used for final oil release may partially decrease the polyunsaturated fatty acids' (PUFAs') quality [13]. Consequently, alternative methods have shown the need for carrying out softer extraction conditions including partial drying, pressing, and centrifugation [14][15][16].…”

Statistical Optimization of Biodiesel Production from Salmon Oil via Enzymatic Transesterification: Investigation of the Effects of Various Operational Parameters

“…In the Atlantic salmon processing industry, 40-50% of the fish body ends up as by-products (heads, frames, and viscera), which have been reported to be abundant in lipids (15-25%) [22]. Several studies have been reported on oil extraction from these by-products [23][24][25][26][27]. The extracted oil has been reported with high yield and good quality with a low extent of oxidation or hydrolysis [23].…”

Proximate Composition and Nutritional Profile of Rainbow Trout (Oncorhynchus mykiss) Heads and Skipjack tuna (Katsuwonus Pelamis) Heads

“…Lipid is another valuable component in fish heads. Glowacz-Rozynska et al found that oil with low peroxide values was obtained from Atlantic salmon ( S. salar ) heads when the extraction temperature did not exceed 15 °C [9]. Dayse et al found that enzymatic hydrolysis was a better method for the extraction of oil from yellowfin tuna ( T. albacares ) heads than cooking, pressing, and chemical solvent methods, as the obtained oil showed lower acidity, lower peroxide values, and higher contents of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) [10].…”