Nutritional indexes, fatty acids profile, and regiodistribution of oil extracted from four discarded species of the Alboran Sea: Seasonal effects

Abstract

The new EU fisheries regulations state that all catches from pelagic fisheries must be landed from the January 1, 2015 on. Consequently, the development of new techniques for the up-grading of these discards is required. The aim of this work was to study the variations of the lipid profile and nutritional value of the oil extracted from four discarded species: axillary seabream (Pagellus acarne), sardine (Sardina pilchardus), horse mackerel (Trachurus mediterraneus), and blue whiting (Micromesistius poutassou). To that end, the proximate composition, the lipid profile, the regiospecific distribution of fatty acids within the glycerol backbone, the nutritional parameters (thrombogenic and atherogenicity indexes and hypocholesterolemic/hypercholesterolemic ratio), and the peroxidability index were determined in each season. All species presented polyunsaturated fatty acids (PUFA) as the major fraction in both the global and the sn-2 profile. DHA presented highly regiospecifity to position sn-2 whereas the tendency of EPA was to occupy sn-1(3) positions. The relative concentration of PUFA occupying sn-2 position varied from 30 to 60% (molar basis).Practical applications: This work proposes an up-grading strategy for the fish oils extracted from four discarded pelagic species. In the last decades, fish oils have been widely employed as source for the production of structured lipids or PUFA concentrates. The choice between both applications depends on the fatty acids regiodistribution within the glycerol backbone. Oils with high PUFA content at the central bond may be selected for the production of structured lipids by using sn1-3 lipases. In this case, the central position remains unmodified. To obtain concentrates it is necessary to release the free fatty acids and subsequently re-esterified them. Consequently, oils with lower PUFA content in the central position are preferred for the production of concentrates by urea complexation or winterization.

Novozyme 435 and Lipozyme RM IM Preferably Esterify Polyunsaturated Fatty Acids at the sn‐2 Position

“…After 24 h, the reaction was stopped by removing the lipases and the molecular sieves by filtration through a sintered glass funnel and the immobilized enzymes were cleaned with hexane and transferred to a 30 mL amber flask until analysis as done in refs. [20, 21].…”

“…[ 22 ] To that end, the esterification products were submitted to an ethanolysis with Novozyme 435 as described in detail elsewhere. [ 20,21 ] Novozyme 435 is a nonspecific enzyme that, in excess of ethanol, becomes highly 1,3 selective. Hence, the MAG produced by ethanolysis are 2‐MAG and its composition is one of the central positions of the substrate.…”

A Simple Enzymatic Process to Produce Functional Lipids From Vegetable and Fish Oil Mixtures

“…(Pontevedra, Spain) while HOSO was purchased from a local supermarket. SO was selected as substrate due to its high lipid and PUFA content, while HOSO was chosen due to its nutritional value (Omega‐6 and oleic acid) . Lipid profiles and fatty acid distributions of SO, HOSO and two mixtures of 1:1 and 1:3 (w:w) SO:HOSO, are listed in Table .…”

“…These products commonly employ fish oils (i.e., cod, tuna, or salmon) and microalgae oils as Omega‐3 sources . In this context, fish by‐catch and/or by‐products, such as sardine, are also regarded as an interesting alternative source of Omega‐3 PUFA, especially considering the progressive discard ban in European fisheries addressed by the 2013 Common Fisheries Policy…”

Evaluation of the potential use of discard species for fish silage and assessment of its oils for human consumption

“…Fish discards and also the waste generated in the fish processing industries involve ecological and environmental concerns (Morales‐Medina et al ., ). The last FAO assessment has estimated global discards from fisheries, including by‐products is approximately twenty million tons per year (FAO, ).…”