Lipid content and fatty acid composition of green algae Scenedesmus obliquus grown in a constant cell density apparatus

The lipids of alga Scenedesmus obliquus grown under controlled conditions were separated and fractionated by column and thin-layer chromatography, and fatty acid composition of each lipid component was studied by gas-liquid chromatography (GLC). Total lipids were 11.17%, and neutral lipid, glycolipid and phospholipid fractions were 7.24%, 2.45% and 1.48% on a dry weight basis, respectively. The major neutral lipids were diglycerides, triglycerides, free sterols, hydrocarbons and sterol esters. The glycolipids were: monogalactosyl diglyceride, digalactosyl diglyceride, esterified sterol glycoside, and sterol glycoside. The phospholipids included: phosphatidyl choline, phosphatidyl glycerol and phosphatidyl ethanolamine. Fourteen fatty acids were identified in the four lipid fractions by GLC. The main fatty acids were C18:2, C16:0, C18:3(alpha), C18:1, C16:3, C16:1, and C16:4. Total unsaturated fatty acid and essential fatty acid compositions of the total algal lipids were 80% and 38%, respectively.     

Isolation and characterization of whey phospholipids

A freeze-dried whey powder was produced by microfiltration of Cheddar cheese whey. A 0.2-micron ceramic membrane in a stainless steel housing unit was used to concentrate components > 400 kDa present in the whey. The experimental whey powder, derived from Cheddar cheese whey, and a commercial whey powder were subjected to proximate analysis, lipid classes, phospholipid classes, and fatty acid compositional analyses. Commercial whey powder and commercial soybean lecithin were subjected to an alcohol fractionation procedure in an effort to alter the ratio of phosphatidyl choline to phosphatidyl ethanolamine and the functionality of dairy phospholipids. The fractionation procedure produced an alcohol-insoluble fraction containing 84% phosphatidyl ethanolamine, whereas the alcohol-soluble fraction resulted in a decrease in the phosphatidyl choline to phosphatidyl ethanolamine ratio. The commercial whey contained a higher ratio of phospholipids to neutral lipids compared with the experimental whey. The classes of phospholipids present within the two wheys were similar, whereas the experimental whey contained a phosphatidyl choline content twice that of the commercial whey, and the phospholipids composition of both wheys differed from the milk fat globule membrane. Comparison of the phospholipids and fatty acid composition of the wheys with the soy lecithin revealed that although the wheys were similar to each other, they differed from the soy lecithin in both the classes of phospholipids present and in the fatty acid composition. These compositional differences may influence the functionality of whey phospholipids.     

Changes in the composition of the rumen and abomasum lipids of sheep from birth to maturity

The composition of the lipids of the rumen and abomasum tissues of foetal (at term), 1 month, 2 month and 1-2-year old sheep grazed on pasture has been determined. The lipid content of the rumen tissues increased from 2.0% at birth to 3.4% in 1-2-year old sheep While that of the abomasum tissues increased from 2.6 to 5.7%. The main change in the neutral lipid fraction was a decrease in the hydrocarbon content from 0.13 % in the rumen tissues and 0.08 % in the abomasum tissues at birth to 0.003% and 0.006% respectively in the 1-2-year old sheep. The main components of the phospholipid fraction of the rumen and abomasum tissues were 34.9- 46.8% phosphatidyl choline; 14.623.5 % phosphatidyl ethanolamine; 14.3-21.1 % sphingomyelin; with smaller amounts of lysophosphatidyl choline (4 13-12.6 %), acidic phospholipids (cardiolipin) (4.1-8 -5 %) and phosphatidyl inositol/phosphaticlyl serine (3.0-5.5 %). No marked changes in phos- pholipid composition with age were noted. The amounts of phosphatidyl choline and phosphatidyl ethanolamine tended to be higher in the abomasum than in the rumen whereas the sphingomyelin content of the rumen tissue phospholipids was generally greater than that of the abomasurn tissue phospholipids. From the fatty acid composition of the triglycerides of the rumen and abomasum tissues it appeared that the foetal triglycerides were largely, though not entirely, of endogenous origin. In contrast the phospholipids of the foetal rumen and abomasum tissues contained di- and poly-unsaturated as well as branched-chain fatty acids in proportions similar to those found in older animals having access to pasture. From these results it is suggested that the phospholipids of the foetus are derived to a considerable extent from the maternal phospholipids.     

Characterization of Shrimp Lipids

Edible shrimp (Penaeus aztecus) tissue contains approximately 1.2% extractable lipids, the majority of which are phospholipids. Data from the gravimetric quantitation of lipid classes isolated by column chromatography indicated that phosphatidyl choline was the predominant phospholipid and cholesterol the predominant neutral lipid in edible shrimp tissue. Fatty acid distribution data indicated that sphingomyelins contained the greatest percent by weight of unsaturated fatty acids while cholesterol esters contained the greatest proportion of saturated fatty acids. Enzymatic hydrolysis followed by gas liquid chromatography of phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl serine indicated that fatty acids located at the β position were more highly unsaturated than those at the α position.     

Seasonal changes in phospholipids of mussel (Mytilus edulis Linne)

The phospholipids of mussels (Mytilus edulis Linne) from the coast of Qingdao were extracted, fractionated and analysed over a 12 month period. The contents of total lipids, neutral lipids, polar lipids and phospholipids were measured. The composition of phospholipids was determined by high‐performance liquid chromatography, and their fatty acid composition was analysed by gas chromatography. The phospholipid content ranged from 3.6 to 6.4 g kg^?1 soft tissue. PE (phosphatidyl ethanolamine) and PC (phosphatidyl choline) were the major constituents. C16:0, C20:5 and C22:6 were the major fatty acids. C20:5 (5.25–23.10%) and C22:6 (6.05–20.42%) varied regularly with the seasonal factors. Their total amounts were high from January to June, which would be an optimal time for the utilisation of the phospholipids of mussels. © 2002 Society of Chemical Industry     

Fumgal lipids. I. Effect of different nitrogen sources on the chemical composition

The effect of three nitrogen sources on the chemical composition of seven fungi, namely: Aspergillus niger, A. luchuensis, Penicillium crustosum, Alternaria tenuis, Rhizoctonia solani, Mucor sp. and Pythium irregulare has been studied. The various fungi showed a great variation with respect to lipid percentage and total lipid content. Lipid content varied from 3.2 to 41.5%. Non-polar lipids were comprised of monoglycerides, diglycerides, free sterols, free fatty acids and triglycerides. The quantitative make-up of the non-polar lipid varied with different nitrogen sources. Palmitic, stearic, oleic and linoleic acids were the major fatty acids while lauric, myristic, palmitoleic, linoleic and arachidic were the minor ones. The fatty acid composition was dramatically changed by changing the nitrogen source. Since different fungi responded differently to changes in nitrogen source, no generalisation could be made. Two-dimensional thin-layer chromatography of the polar lipid fraction of these fungi revealed the presence of a maximum of fifteen spots. Phosphatidyl choline, phosphatidyl ethanolamine and phosphatidyl inositol were the major spots while lysophosphatidyl choline, lysophosphatidyl ethanolamine and phosphatidyl glycerol were present in smaller quantities. In comparison to phospholipids, glycolipids (except sterol glycoside) were present in relatively lower concentration. Pythium irregulare was very characteristic in having no glycolipids at all.     

Changes in phospholipids of buffalo meat during processing and storage

Effect of broiling and pressure cooking as well as alterations during refrigerated (4°C) and frozen (-10°C) storage on the phospholipids of adult male buffalo muscles viz. Triceps brachii (TB), Longissimus dorsi (LD) and Biceps femoris (BF), i.e. from three different locations were studied. Muscles differed significatly in their total lipid and phospholipid content. Cooking methods significantly altered the total phospholipid content and its fractions. Storage period did not show any significant effect on total phospholipids during refrigerated and frozen storage, whereas certain phospholipid classes viz. lysophosphatidyl choline and lysophosphatidyl ethanolamine + sphingomyelin increased significantly and major phospholipid classes viz. phosphatidyl choline and phosphatidyl ethanolamine decreased significantly. The changes in phospholipid classes were similar both in refrigerated and frozen samples but relatively more pronounced in the former. Palmitic, stearic, oleic and linoleic acids were the four predominant fatty acids in the phospholipids of buffalo meat. The effects associated with the location of muscles were evident. Differences in fatty acid composition of individual muscles in response to heat processing were observed. Heat processing significantly increased the total saturates in TB and LD muscles while it decreased in BF. The total monounsaturated and total polyunsaturated fatty acids of phospholipids decreased during refrigerated and frozen storage indicated by a significant decreass in oleic, linoleic and arachidonic acids.     

Phospholipids of marine origin. The lantern fish (Lampanyctodes hectoris)

Lantern fish of the species Lampanyctodes hectoris were shown to contain phospholipids (10 g kg^?1) and non-phosphorylated lipids (140 g kg^?1). The phospholipid fraction consisted of phosphatidyl choline (47% of total phospholipids), phosphatidyl ethanolamine (42%), phosphatidyl serine (3%), phosphatidyl inositol (1%), sphingomyelin (4%), lyso-phosphatidyl choline (1%) and cardiolipins (2%). Lantern fish (L hectoris) meals normally contain unacceptably high lipid contents (150 g kg^?1 and over); this characteristic was found not to be due to a high phospholipid level in the lantern fish. The major fatty acid of the phospholipids was C22:6n-3 (25% total fatty acids) followed by C16:0 (18%), C18:ln-9 (16%) and C20:5n-3 (8%). This distribution was different from that of the non-phosphorylated lipids where the major fatty acid was C16:0 (21%) followed by C18:ln-9 (19%), C20:5n-3 (11%), C20:l (7%) and C22:6n-3 (7%). The lantern fish press oil and residual meal lipids had fatty acid distributions similar to those of the non-phosphorylated lipids.     

Changes in milk fat phospholipids during lactation

Changes in lipid composition were studied in milk obtained on postpartum d 3 (colostrum), 7, 42, and 180 from 12 Holstein cows. Triglycerides, 96 to 97% of total lipids, were relatively constant during lactation. Phospholipids and cholesterol declined with advancing lactation. Concentrations of the fatty acids synthesized within the mammary gland, C10:0 to C16:0, increased about 50% from 7 to 42 d of lactation. During this period, compensatory decreases were observed in C18:1. The phospholipids were separated into five major classes: sphingomyelin, phosphatidyl choline, serine, inositol, and ethanolamine for fatty acid analysis. The changes that occurred in milk total fatty acids were reflected in phosphatidyl phospholipid fatty acid composition: an increase in medium-chain fatty acids and a decrease in polyunsaturated fatty acids of 18, 20, and 22 carbon atom chain length as lactation progressed. These changes are consistent with the theory that milk phospholipids are synthesized de novo entirely in the mammary gland.     

Variability in the major lipid components of four market classes of dry edible beans

The lipid composition of dry edible beans (Phaseolus vulgaris L) was characterised and the variability between four US market classes (navy, dark red kidney, pinto and Black Turtle Soup) was determined. The total lipid content of the beans ranged from 1–8 to 2–6 g per 100 g dry weight. Triacylglycerol esterified sterified glucoside and phosphatidylcholine were identified as the major lipid class components of the neutral lipid, glycolipid and phospholipid fractions, respectively. The fatty acids were highly unsaturated: linolenic acid was the major fatty acid. Three sterols, campesterol, stigmasterol and β-sitosterol, were identified. The lipid and fatty acid contents of the bean classes were significantly ( P <0–05) different. Principal component analysis of the total lipid components resulted in the extraction of four factors, which accounted for 93.3% of the variability of the data set. These factors were characterised as the (I) fatty acid. (II) sterol. (III) lipid class, and (IV) oleic acid factors.     

LIPIDS OF CURED CENTENNIAL SWEET POTATOES

SUMMARY –Lipids isolated from cured Centennial sweet potatoes were identified and quantitated by a combination of column and thin layer chromatography. These lipids were shown to consist of 42.1% neutral lipids, 30.8% glycolipids and 27.1% phospholipids. Triglycerides and steryl esters were the major lipids of the neutral fraction. Among the phospholipids, phosphatidyl ethanolamine, phosphatidyl choline and phosphatidyl inositol were the most abundant. Galactolipids and the steryl glucosides were also present. The predominant fatty acids were stearic, palmitic, oleic, linoleic and linolenic.     

Phospholipids of marine origin. IV. The abalone (Haliotis midae)

Phospholipids of the abalone were separated into component fractions by chromatography on silicic acid. The phospholipids were remarkable for the presence (6%) of an unusual sphingolipid liberating 2-amino-ethylphosphonic acid on hydrolysis, and for the high proportion of plasmalogens (23%). The presence of phosphatidyl ethanolamine plus ethanolamine plasmalogen (32%), phosphatidyl serine (5%), phosphatidyl inositol (5%), phosphatidyl choline (41%) and sphingomyelin (1%) were also demonstrated. The fatty acid distribhion in the phospholipids, the non-phosphorylated lipids and the unusual sphingolipid was determined by gas chromatography. In general these results show a similarity between the phospholipid and the non-phosphorylated lipid fatty acids, the former being richer in long chain polyunsaturated fatty acids. Fatty acids of the unusual sphingolipid were outstanding for the high palmitic (53%) and stearic acid (15%) content.     

Phospholipids determination in vegetable oil by thin-layer chromatography and imaging densitometry

A rapid reliable method was developed to measure vegetable oil phospholipid content by thin-layer chromatography–imaging densitometry. Phospholipid samples were obtained from crude soybean oil by water degumming and then analyzed and quantified by thin-layer chromatography and imaging densitometry. Phosphatidyl choline (PC), phosphatidyl ethanolamine (PE) and phosphatidyl inositol (PI) standard curves were generated. The total phospholipid content of the oil was 1.12–1.26%, of which 27.1 ± 1.86% was PC, 22.7 ± 0.45% was PE, while PI accounted for 17.2 ± 0.85% of the total. A high correlation coefficient of 0.985 was found for reproducibility of pixel area (OD*mm) at a constant concentration of standard phospholipid. Regression analysis of the pixel area vs the phospholipid (PC, PE, and PI) weights (μg) generated R² greater than 0.983. Thin-layer chromatography–imaging densitometry proved a useful tool for rapid determination and quantification of the major phospholipids in soybean oil.     

Supercritical fluid extraction and characterization of lipids from algae Scenedesmus obliquus

Supercritical carbon dioxide (SC-CO2) extractions (with and without ethanol as an entrainer) were carried out to remove lipids and pigments from protein concentrate of green algae (Scenedesmus obliquus) cultivated under controlled conditions. The content and fatty acid composition of algal lipids using column, thin-layer (TLC) and gas-liquid chromatography (GLC) were determined. Absorption spectra of extracted fractions showed the predominance of chlorophyll A (lambda max at 410 nm). Single step supercritical carbon dioxide (SC-CO2) extraction resulted mostly in removal of neutral lipids and a part of glycolipids, but phospholipids were not extracted. Addition of ethanol to SC-CO2 increased the amount of glycolipids and phospholipids in the extract. TLC pattern of algal lipids showed that the main part of neutral lipids consisted of diglycerides, triglycerides, hydrocarbons, free sterols, and sterol esters. The glycolipids were mostly monogalactosyl diglyceride, digalactosyl diglyceride, esterified sterol glycoside, and sterol glycoside. In phospholipids, phosphatidyl choline, phosphatidyl glycerol, and phosphatidyl ethanolamine were the main compounds. Fatty acid composition patterns indicated the main fatty acids to be 16:0, 16:1, 16:2, 16:3, 16:4, 18:1, 18:2, and 18:3(a). Relatively high recovery of polyunsaturated fatty acids and essential fatty acids in supercritical fluid extracted algal lipids and proteins isolates were observed.     

Lipid Content and Fatty Acid Composition in Bamboo Shoots

Lipids from bamboo shoots (Phyllostachys pubescens), peeled and divided from top to base, were extracted and fractionated into three classes, and each class separated into constituent components by thin-layer chromatography (TLC). Fatty acid composition and amount of separated lipids were determined. Total lipids (TL) ranged from 800 (top) to 380 mg (base) per 100g fresh weight and the ratio of nonpolar lipids (NPL):glycolipids (GL):phospholipids (PL) was about 17:27:56. The main fatty acids of the three lipid classes were palmitic, linoleic and linolenic acids, but composition was remarkably different among these fractions. The fatty acid composition of triglycerides (TG) was similar to the original NPL. Palmitic acid was almost all located in 1-, 3-position, linoleic acid mainly located in 2-position of TG, while linolenic acid was distributed in each position. Digalactosyl diglyceride (DGDG) and monogalactosyl diglyceride (MGDG) were the main components of GL; the average of the former had about 37% linoleic and 29% linolenic acids, while the latter had about 25% linoleic and 62% linolenic acids. Bamboo shoots contained 9 PL fractions, the major being phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE). PC contained about 48% linoleic, 31% palmitic and 11% linolenic acids, and PE also had the similar tendency as PC.     

Changes in the composition of the fatty acids and aldehydes of meat lipids after heating

The effects of heating at 132°C on the fatty acids and fatty aldehydes of neutral lipids and phospholipids of lean beef, veal, lamb, pork and chicken were studied. Heating caused hydrolysis of the plasmalogens in the phospholipids, and varying amounts of the liberated fatty aldehydes were recovered in the neutral lipid fractions. Beef phosphatidyl choline lost more polyunsaturated fatty acids than that of the other meats. Beef and veal phosphatidyl ethanolamine lost more polyunsaturated fatty acid than that of lamb, pork or chicken, but the effect was obscured by the influx of fatty acids from elsewhere into this fraction after heating.     

Lipolytic and oxidative changes in two Spanish pork loin products: dry-cured loin and pickled-cured loin

Lipolytic and oxidative changes were studied in two typical meat products from pork loin, dry-cured loin (DCL) and pickled-cured loin (PCL). Neither product registered changes in the percentages of the main lipid fractions: non polar lipids, phospholipids and cholesterol. However, in dry cured loin an important decrease was recorded in the main phospholipid classes, phosphatidyl choline and phosphatidyl ethanolamine. Muscle lipolytic enzymes were active in both products, and were accompanied by a significant increase in free fatty acids, from 0.580% (of total lipid) in fresh loin to 5.65 in DCL and 2.95% in PCL. With respect to oxidative changes, the peroxide value decreased in both products, and the TBA number only increased in PCL.     

太平洋磷虾脂肪酸的气相色谱-质谱法分析

通过采用Folch法从太平洋磷虾（Euphausia Pacifica）中提取总脂,通过硅胶柱层析分析了总脂中中性脂、糖脂和磷脂的组成情况,并采用气相色谱．质谱（GC-MS）法对这三类脂质的脂肪酸组成进行了分析和比较。结果表明,太平洋磷虾的总脂含量为15．16％,其中中性脂占I总脂含量的70．19％,磷脂占25．15％,糖脂占4．66％。通过气相色谱-质谱分析从太平洋磷虾的总脂中共鉴定出20种脂肪酸,其中不饱和脂肪酸11种,占总脂肪酸总量的55．54％。对中性脂、糖脂和磷脂的脂肪酸组成进行的分析比较表明,不同脂质中脂肪酸组成及其含量存在一定的差异。本文旨在为太平洋磷虾的营养评价和高值化利用提供一定的基础数据。     

Phospholipids of marine origin. V. The crab--a comparative study of a marine species (Cyclograpsus punctatus) and a fresh water species (Potamon)

A comparison has been made between phospholipids extracted from a marine crab and from a fresh water crab. Marine crab (body and viscera) contained a phospholipid fraction which liberated 2-aminoethylphos-phonic acid upon hydrolysis, while this substance was absent from the fresh water crab. Marine crab phospholipids had a higher content of phosphatidyl choline (57%), a higher content of phosphatidyl serine (5%) but a lower content of phosphatidyl ethanolamine (22%) than phospholipids from the fresh water crab (respective values: 52, 2 and 27%). Marine crab phospholipids and non-phosphorylated lipids were richer in C20 plus C22 fatty acids but poorer in C18: 2 acid, than were the corresponding lipids from the fresh water crab.     

Lipid Composition of Field Pea (Pisum sativum cv Trapper) Seed and Starch

The total lipids in field pea seeds and refined starch were extracted by five aqueous/organic solvent systems and the greatest yield of total. neutral and polar lipids was obtained with hot n-propanol-water (3:1 v/v). Lipids extracted from field pea seeds represented 2.9% of the seed weight and consisted of 43.2% neutral lipids, 3.2% glycolipids and 53.6% phospholipids. The major components of the three fractions were 70% triacylglycerol in neutral lipid, 28% esterified sterol glycoside in glycolipid and 55% phosphatidylcholine in phospholipid. The purified starch fraction contained 0.22% surface lipids and 0.09% internal lipids. The surface lipids were primarily sterol esters and free fatty acids while only free fatty acids were found in the internal lipids. The ability of lysophospholipids and fatty acids to complex with field pea starch was demonstrated by differential scanning calorimetry and X-ray diffraction, respectively.