(2002). The Effects of Harmful Algal Blooms on Aquatic Organisms. Reviews in Fisheries Science: Vol. 10, No. 2, pp. 113-390.

The Effects of Harmful Algal Blooms on Aquatic Organisms

Amino acids, fatty acids, and dietary fibre in edible seaweed products

A spectrophotometric assay for lipid peroxides in serum lipoproteins using a commercially available reagent.

Recent developments on the production of omega-3 fatty acid concentrates have been reviewed with an emphasis on the scientific articles published from 2000. At first, a description of the role of essential fatty acids in the organism and the influence of omega-3 fatty acids in human health is presented. An account of the review articles that have been published in previous years related to the production or isolation of omega-3 fatty acids is then provided. The publications that have appeared over the last 8 years have been reviewed under two groupings, one involving the production of omega-3 from fish, and the other involving the isolation from alternative sources. Fish is the major source of omega-3 fatty acids and the fish oil extraction processes have been considered firstly, then the fish oil refining processes are presented and finally the omega-3 concentration from fish oil. Some considerations on the stability of polyunsaturated fatty acids against hydrolysis and oxidation and the procedures to avoid it are also presented at the end of this review. Industrial relevance Omega-3 polyunsaturated fatty acids are being used quite extensively in the food industry to obtain omega-3 enriched food products. Most of the commercial concentrates that can be found nowadays are the omega-3 ethyl ester derivatives. However, research is ongoing to obtain the more natural and better digestible triglyceride concentrates. We present here a review of the most recent advances, regarding the production of omega-3 concentrates from the very first raw material that contains them from which they should be extracted to the omega-3 concentrates stabilization. In between, a good number of different technologies that are being industrially applied, or still under investigation, are reviewed. One of the technologies with high expectation is supercritical fluid technology, and it finds a relevant place in the review here presented. Industries involved on innovation, require rapid overviews of the different possibilities open for production, and in that sense, this review is expected to be of interest.

Production of omega-3 polyunsaturated fatty acid concentrates: A review

Mechanisms for the autoxidation of polyunsaturated lipids

Open-tubular gas chromatographic analysis of fatty acids in the lipids from the seeds of 20 species of Gymnospermae showed that they all contained nonmethylene-interrupted polyenoic (NMIP) acids as minor components and palmitic, oleic, linoleic and α-linolenic acids as major components. The NMIP acids have an additional 5,6-ethylenic bond in ordinary plant unsaturated fatty acids and the following C2 elongation acids:cis-5,cis-9-octadecadienoic acid (5,9–18∶2) (I); 5,9,12–18∶3 (II); 5,9,12,15–18∶4, 5,11–20∶2, 5,11,14–20∶3 (III); and 5,11,14,17–20∶4 (IV). The main NMIP acids found in neutral lipids are I in two species ofTaxus, II in seven species of Pinaceae, III in two species of Podocarpaceae,Torreya nucifera, Cycas revoluta, andGinkgo biloba, and III and IV in each of three species of Taxodiaceae, and Cupressaceae. The polar lipids constitute the minor fraction of seed lipids in general. The content and composition of NMIP acids in these lipids differe considerably from those in neutral lipids. Analysis of the partial cleavage products of triacylglycerols showed that the NMIP acids distribute mainly in the 1,3-position.

cis-5-olefinic unusual fatty acids in seed lipids of gymnospermae and their distribution in triacylglycerols

A method for the stereospecific analysis of triacyl-sn-glycerols by high-performance liquid chromatography (HPLC) on a chiral column is described. Triacyl-sn-glycerols were partially degraded with ethyl magnesium bromide, and the monoacylglycerols produced were separated as 1- and 2-monoacylglycerol fractions by thin-layer chromatography on boric acid-impregnated silica gel plates. The 1-monoacylglycerols were resolved intosn-1 andsn-3 monoacylglycerol fractions by HPLC on a chiral column (Sumichiral OA-4100) after derivatization with 3,5-dinitrophenyl isocyanate. Fatty acid methyl esters obtained from the original triacyl-sn-glycerols, 1- and 2-monoacylglycerol fractions, andsn-1 andsn-3 monoacylglycerol fractions were analyzed by gas chromatography on open-tubular columns. Stereospecific acyl distributions in triacyl-sn-glycerols were calculated from the data. The acyl distributions of several oils were obtained. The method is rapid, simple and gave reproducible results.

Stereospecific analysis of triacyl-sn-glycerols by chiral high-performance liquid chromatography

Analytical methods to obtain the detailed compositions of the fatty acids in oils containing more than one conjugated octadecatrienoic acid by open-tubular gas liquid chromatography (GLC) and by reversed-phase high performance liquid chromatography (HPLC) were established. Effective GLC separations ofcis,trans,trans-9,11,13-octadecatrienoic acid (ctt-9,11,13–18∶3),ctc-9,11,13–18∶3,ttc-9,11,13–18∶3,ttt-9,11,13–18∶3,ttc-8,10,12–18∶3, andttt-8,10,12–18∶3 were obtained with an opentubular column coated with the nonpolar liquid phase OV-1 using an instrument having all-glass carrier gas pathways. The HPLC method also gave satisfactory separations for the isomeric conjugated octadecatrienoates on the basis of number of thecis andtrans double bonds. Two or three minor conjugated trienoic acids were found along with the principal conjugated trienoic acid in tung oil, and seed oils of cherry,Prunus sp., Momordica charantia, Trichosanthes anguina, Punica granatum, Catalpa ovata, andCalendula officinalis. The mechanism for the formation of the conjugated trienoic acid mixtures in the seed oils is discussed. TheC. ovata seed oil also containedct andtt-9,12-octadecadienoic acids. Thett isomer is presumed to be a precursor ofttc-9,11,13–18∶3, the main conjugated trienoic acid in this oil.

Occurrence of mixtures of geometrical isomers of conjugated octadecatrienoic acids in some seed oils: Analysis by open‐tubular gas liquid chromatography and high performance liquid chromatography

The acetone extracts from three samples of the hepatopancreas of the poisonous scallops obtained on the Okhotsk Coast of Hokkaido Island were fractionated into two parts, hexane soluble fraction (fraction H) and 85% aqueous ethanol soluble fraction (fraction E) by partition to two layers. The majortoxic components in the mouse assay of “diarrheic shellfish toxin” by intra-peritoneal injection were found to be free unsaturated fatty acids showed the following toxicity in MU per g, 18:1 n-9 35, 18:2 n-6 83, 18:3 n-3 167, 18:4 n-3 83, 20:5 n-3 167, and 22:6 n-3 83, respectively. Toxicity of the fraction Hin MUper g was much lower than that of the fraction E. However, the toxicity of the fraction H per 1 g of the hepatopancreas was about twice that of the fraction E, since the fraction Hwas much more abundant than the fraction E in the hepatopancreas. The method for the assay of the diarrhetic shellfish toxin must be reexamined by considering the toxic effect of the free unsaturated fatty acids.

Toxic effect of free unsaturated fatty acids in the mouse assay of diarrhetic shellfish toxin by intraperitoneal injection.

Improved procedures of the Swoboda and Lea method for the determination of peroxide values (POV) of fats and lipids are presented. After oxidation of iodide to iodine with the sample for 5 min under an inert atmosphere, an excess of the iodide ion is immediately converted to cadmium complex for protection from atmospheric oxygen. The iodine is measured colorimetrically at 358 or 410 nm, and POV is calculated from the absorbance. This method permits the rapid determination of POV with a small amount of sample at a moderate cost using usual glasswares. For the analysis of lipids in biological materials or food products, the chloroform solution obtained by the Bligh and Dyer method is directly subjected to this procedure without evaporation of the solvent. Conversions between POV obtained by the different methods are discussed.

Toru Takagi

Papers

cis-5-olefinic unusual fatty acids in seed lipids of gymnospermae and their distribution in triacylglycerols

Stereospecific analysis of triacyl-sn-glycerols by chiral high-performance liquid chromatography

Occurrence of mixtures of geometrical isomers of conjugated octadecatrienoic acids in some seed oils: Analysis by open‐tubular gas liquid chromatography and high performance liquid chromatography

Toxic effect of free unsaturated fatty acids in the mouse assay of diarrhetic shellfish toxin by intraperitoneal injection.

Determination of peroxide value by the colorimetric iodine method with protection of iodide as cadmium complex