Fatty acid profiles of 80 vegetable oils with regard to their nutritional potentialThe current concern for fat intake in western countries has raised the question of the individual fatty acid (FA) impact on health. This important issue has strengthened the awareness of nutritionists and food manufacturers for the control of the FA profile of food products. The aim of this review is to provide a classification of the FA profiles of 80 vegetable oil sources, according to their nutritional potential. The first part of the review focuses on lipoprotein metabolism, and on the impact of each dietary FA on blood lipid composition (LDL-cholesterol, HDL-cholesterol and circulating triacylglycerols). In the second part of the review, the oil sources are clustered by similar FA profiles, and the classification is discussed with regard to the individual FA action on blood lipid composition. Apart from the major vegetable seeds, the clustering highlighted some interesting nutritional oil sources containing mainly a-linolenic acid (camelina, linseed, perilla and stock oils), or interesting amounts of the two essential FA (purslane, chia, raspberry seed, sea buckthorn seed and salicorn oils). Furthermore, this classification provides a useful tool for the formulation of the FA profile of food products. A fatty acid is a hydrocarbon chain, saturated or not, with a methyl group at one end (n), and a carboxylic function at the other (D). An SFA, as its name suggests, possesses an alkane-like structure with a fully saturated hydrocarbon chain, while a MUFA has one double bond, and a PUFA several ones, with these double bonds being naturally in cis configuration [2]. KeywordsVegetable oils are mainly triacylglycerols, made by esterification of three FA on the glycerol skeleton [3]. The three positions are not equivalent when it comes to bioavailability, and a fortiori to health. Indeed, the sn-2 position is conserved during the whole digestive process, which explains why in natural fats and oils the most physiologically important FA are esterified on the sn-2 position [4-6].In vegetable sources, unsaturated FA are mainly esterified on this important sn-2 position [7].Among PUFA, the most important families are the wellknown n-3 and n-6 fatty acids [8]. These two families are similar as they both comprise a precursor, namely ALA for the n-3 and linoleic acid (LA) for the n-6 family ( Fig. 1), and terminal products obtained by a succession of elongations and desaturations during the metabolism, the two groups of FA sharing the same long-chain converting enzymes [2]. These compounds are said to be essential because the human body is unable to synthesize them, although it can metabolize them to longer-chain derivatives. So the diet must cover the organism need for theseThus, a competition exists between n-3 and n-6 FA, with an excess of one group causing a significant decrease in the conversion yield of the other (Fig. 2) (LA, bottom), showing the double bonds in the hydrocarbon chain. The numbers represent the carbon atoms bearing a ...

Protein hydrolysates from salmon heads were obtained by enzymatic treatment with Alcalase ® 2.4L. Response surface methodology (RSM) allowed optimization of temperature, enzyme/substrate, and pH leading to various hydrolysates (11.5% to 17.3% hydrolysis degree [DH]) and protein recovery ranging from 47% to 70%. Size exclusion chromatography of hydrolysates showed that small peptides increased only at high DH. The nitrogen solubility index (NSI) of hydrolysates was higher than 75% over a wide range of pH values, whereas hydrolysates with high DH had the best solubility. Emulsifying capacity, emulsion stability, and fat absorption capacity were better when DH was low.

Fresh salmon heads were submitted to controlled proteolysis using food‐grade commercial enzymes (Alcalase®, Neutrase® and Protamex™). The release of oil under mild conditions (60°, 2 h) compared favourably with organic solvent extraction (19.8% vs. 21.5%). Lipids extracted by solvent and lipids resulting from enzymatic processes displayed a similar content of PUFA (about 35%), mainly eicosapentaenoic acid (EPA; 8.4% vs. 7.7%) and docosahexaenoic acid (DHA; 12.1% vs. 11.9%). Thin‐layer chromatography (TLC‐FID Iatroscan) showed that the polar lipid fraction accounted for 55% of total lipids (phosphatidylethanolamine, 20.7%; phosphatidylcholine, 14.8%). Salmon head phospholipids may be more effective carriers of highly unsaturated fatty acids to specific tissues than triacylglycerols, as shown by their content in EPA (10.3 and 6.9%, respectively) and DHA (33.1 and 9.1%, respectively).

Commercial proteases (Alcalase, Neutrase, and Flavourzyme) were tested for their ability to release the oil content of marine by-products (salmon heads). The amount of oil (17%) obtained after 2 hours was close to that obtained by the chemical extraction method (20%). Lipolysis of the oil was carried out with Novozym SP398 to obtain a mixture of free fatty acids and acylglycerols (24 hours 45% hydrolysis). The mixture was filtered on a hydrophobic membrane to discriminate between high melting saturated fatty acids and low melting acylglycerols. The sum of total polyunsaturated fatty acids increased from 41.6% in the crude oil to 46.5% in the permeate. The docosahexaenoic acid content increased from 9.9% to 11.6%, and the eicosapentaenoic acid changed from 3.6% to 5.6%. Data from differential scanning calorimetry DSC and from thin layer chromatography coupled with flame ionization detection (TLC-FID) differed significantly between permeate and retentate. A re-esterification of the free fatty acids in the permeate with Lipozyme IM was carried out to increase the amount of long chain acylglycerols.

The objective of this paper