Optimisation of oil extraction from sardine (Sardina pilchardus) by hydraulic pressing

Abstract

Summary The aim of this study was to evaluate the influence of the processing conditions (pretreatment temperature: 5–55 °C, pressure: 60–120 bar and number of pressing stages: 1–3) on the yield and quality (free fatty acids, peroxide value, p‐anisidine and Rancimat induction period) of the oil extracted from whole sardine by hydraulic pressing. Experimental factors were investigated by a designed experiment and optimised by response surface methodology. A maximum yield of oil, 12.47%, was obtained at 55 °C, 60 bar and two pressing stages. Regarding oil quality, it was found minimum values for acidity (0.25% oleic at 55 °C, 60 bar and one pressing stage) and for peroxide value (0.29 meq kg−1 oil at 5 °C, 60 bar and one pressing stage). Hence, the opposite effect of pretreatment temperature and number of pressing stages on the yield of oil and on its oxidation parameters suggested applying the weighted‐sum method as multiobjective optimisation technique.

High Quality Oil Extracted from Sardine By‐Products as an Alternative to Whole Sardines: Production and Refining

“…However, the deodorization of the bleached samples carried out by distillation significantly increased the samples PVs from 2.21 meq to 4.55 meq O 2 /kg in case of sardine oil and from 2.88 to 3.78 meq O 2 /kg in case of sardine by‐product oil (Table ). Despite this increase of the PVs, the obtained values are still lower than those reported by García‐Moreno et al (from 0.33 to 5.74 meq O 2 /kg) and Chakraborty and Joseph (from 3.62 to 8.25 meq O 2 /kg). As already mentioned, the reason for this can be found in differences between used raw materials, their manipulation, and storage until processing as well as the applied refinement procedures.…”

“…It is well known that these processes are usually more intense in the post‐mortem period of small pelagic fish . However, García‐Moreno et al obtained the lowest FFA values in oils extracted at the highest processing temperature and this has been explained by the fact that at temperatures above 45 °C, lipases from sardines become unstable. As the temperature applied in our study was significantly higher, this could also explain the low FFAs content of the investigated oils.…”

Enzymatic extraction of oil from yellowfin tuna (Thunnus albacares) by‐products: a comparison with other extraction methods

“…This result confirms the idea that palmitic acid is the main saturated fatty acid (SFA) in many saltwater species, accounting for about 70% of the total SFAs (Özogul et al ., ), and also corroborates the results obtained by García‐Moreno et al . (), who observed that palmitic acid was also highly present in the gross oil of whole sardines (20% of the total amount of SFAs) ( Sardina pilchardus ) extracted with the hydraulic pressing method. Fatty acid profile similar to that obtained by the IO was observed by Eom et al .…”

“…Fish oil is the most important source of polyunsaturated fatty acids (PUFAs), especially the omega-3 fatty acids eicosapentaenoic acid (C20:5n-3-EPA) and docosahexaenoic acid (C22:6n-3-DHA), both of which play a beneficial role in human health. The benefits related to intake of EPA and DHA fatty acids have attracted increased interest over recent decades by the pharmaceutical and food industries (Garc ıa- Moreno et al, 2014). Therefore, the production of fish oil rich in PUFAs is a good opportunity to add value to fish by-products and increases the competitiveness of the fishing industry (Rubio-Rodr ıguez et al, 2012).…”

“…According to Garc ıa-Moreno et al (2014), current scientific literature still lacks studies on fish oil extraction methods. Various studies have performed EHO of fish by-products to achieve better oil extraction using cod by-products (Gadus morhua) (Dauksas et al, 2005), black scabbardfish (Aphanopus carbo) (Batista et al, 2010), sardine heads (Sardina pilchardus) (Dumay et al, 2009) and Indian carp viscera (Hathwar et al, 2011).…”