Changes in lipids of pigeon “milk” in the first week of its secretion

Pigeon “milk” (PM) collected from the crop of 1- to 5-day-old squabs was analyzed to examine whether there were changes in lipid composition during the first week of secretion. The high PM fat content (9–11%) remained fairly constant in the first 5 days of secretion. The mean percentage of neutral lipids, glycolipids and phospholipids was 80, 12 and 8%, respectively. Unlike the content of neutral lipids, glycolipid and phospholipid levels increased significantly between day 1 and day 5 of secretion. Triglycerides, the major neutral lipids, decreased by 24% between day 1 and day 5, while free sterols, monoglycerides and hydrocarbons increased by 8%, 11% and 2.5%, respectively, during the same period; diglycerides and sterol esters, however, remained unchanged. The ratio of saturated to unsaturated fatty acids was 0.27 and it remained unchanged. Medium-chain (C₁₀, C₁₂ and C₁₄) and oddchain (C₁₅ and C₁₇) fatty acid contents were low. Fatty acids longer than C₂₀ were absent. Palmitic acid, the major saturated fatty acid, increased by 42% from day 1 to day 5, whereas stearic acid decreased by 48% during the same period. Oleic acid, the predominant unsaturated fatty acid, also decreased from 51 to 45% between the first and fifth day of PM secretion. Polyunsaturated acids (18∶2, 18∶3 and 20∶4) accounted for 26% and 30% of the total fatty acids on day 1 and day 5, respectively. Although lipid changes in the crop of squabs prior to collection of samples cannot totally be ruled out, the nature of lipid changes is likely to reflect cellular breakdown that precedes PM secretion by parent pigeons.     

Brain mitochondrial incorporation of elongated fatty acids into phospholipids

The characteristics patterns and asymmetric distribution of phospholipid fatty acids suggest precise control mechanisms. Our investigations were designed to assess mitochondrial fatty acid elongation and their pattern of incorporation into complex lipids. Fatty acid chain elongation in the total lipid fraction occurred primarily with the more abundant fatty acids present. Elongation patterns in free fatty acids were similar to the total lipid fraction except C_20:4 and C_22:4 were formed to slightly greater extent. Choline glycerophosphatide and ethanolamine glycerophosphatide displayed different patterns of elongation. Choline glycerophosphatide contained more elongated longer chain polyunsaturated fatty acids, while ethanolamine glycerophosphatide contained greater amounts of elongated shorter chain saturated and monounsaturated fatty acids. These results suggest that fatty acid elongation may play a specific role in fulfilling mitochondrial phospholipid fatty acid requirements.     

Lipid components of borage (Borago officinalis L.) seeds and their changes during germination

The changes in composition of total and neutral lipids (NL) as well as glycolipids (GL) and phospholipids (PL) of borage (Borago officinalis L.) seeds, germinated in the dark at 25^°C for 10 d, were studied. Total lipids constituted 34.0% of the dry matter of borage seeds. During germination, the content of total lipids was decreased by 95%. NL accounted for 95.7% of total lipids prior to germination and were composed of triacylglycerols (TAG; 99.1%), diacylglycerols (DAG; 0.06%), monoacylglycerols (MAG;0.02%), free fatty acids (FFA;0.91%), and sterols (0.02%). The content of TAG was significantly (P≤0.05) decreased, while that of other components, such as MAG and FFA, significantly (P≤0.05) increased during germination. However, the content of DAG did not change. GL and PL accounted for 2.0 and 2.3% of total lipids, respectively, and their contents significantly (P≤0.05) increased as germination proceeded. The thin layer chromatography-flame-ionization detection studies showed that phosphatidylcholine (PC; 69.7%) was the major PL present. The total content of phosphatidylserine (PS) and phosphatidylethanolamine (PE), which were coeluted, was 18.2%; phosphatidic acid (PA) was present at 11.2% of the total PL fraction. Lysophosphatidylcholine was detected at 0.9%. The proportion of PC, PS, and PE significantly (P≤0.05) decreased during germination, but that of PA increased (P≤0.05) markedly. The fatty acid composition of lipid fractions changed as germination proceeded. The predominant fatty acids of total lipids, NL, and GL were linoleic and linolenic acids, while those of PL were linoleic and palmitic acids. The present study demonstrated that the overall changes of lipids seen in borage seeds during germination agree well with results for other oilseeds. Changes in lipid compositions during germination result from the formation of tissues and metabolic interconversion of lipid classes. Rapid changes in lipid composition during seed germination may enhance the nutritional value of the sprouts.     

Lipid Class and Fatty Acid Composition of Psoralia corylifolia Seed

The purified crude lipid of Psoralia corylifolia seeds was subjected to lipid class and fatty acid analysis by thin layer and gas chromatography. The lipid classes identified were triacyl glycerol, free fatty acid, diacyl glycerol, mono acyl glycerol, hydrocarbon-waxester and polar lipid fractions. Most of the fractions were found to contain high level of C_18:1 while C_18:0, C_18:3 and C_20:0 were also found to be present in all the lipid fractions. It has been observed that the diacyl and monoacyl glycerol fractions contain significant amounts of C_14:0 and C_18:0 while the hydrocarbon-waxester fraction was rich in C_22:0. The polar lipids contain high level of C_18:3 and low level of C_18:1 as compared to other lipid fractions. The fatty acid composition of the whole oil was also determined and found to be similar to other fractions. Unidentified long chain fatty acids were also present in significant amounts in all the lipid fractions.     

Lipid composition of commercially canned single-strength orange juice

The lipid composition of commercially canned single-strength orange juice ranged from 84–101 mg/100 ml juice (overall mean 95 ± 6). Phospholipid phosphorus, expressed as mg/100 ml juice, showed a range of from 1.56–1.95, while phospholipid phosphorus/lipid values (as µg-P/mg lipid) were within a very narrow range, 18.9 ± 1.1. The percentage distribution of lipid classes in these juices was 24–35% neutral lipids, 18–23% resin acids and glycolipids, and 43–53% phospholipids and other polar lipids. Five fatty acids, i.e. C₁₆, C_16:1, C_18:1, C_18:2, and C_18:3, accounted for over 93% of all fatty acids. The relative percentages of C_18:2 and C_18:3 differed between seasonal juices. The lipid composition does not warrant inclusion in nutritional labeling; however, lipid levels may be useful in detecting adulteration.     

Supplemental dietary flaxseed oil affects both neutral and phospholipid fatty acids in cultured tilapia

This work aimed to evaluate the neutral lipid (NL) and phospholipid (PL) classes in tilapia (Oreochromis niloticus) muscle tissue. Tilapias were raised in captivity for a period of 5 months with increasing levels (0, 1.25, 2.50, 3.75, and 5.00%) of flaxseed oil [source of α‐linolenic acid (LNA), 18:3n‐3] in substitution for sunflower oil (control). The NL/PL ratio was 1.9, and 45 fatty acids were determined for both classes of lipid. The class totals of n‐3 acids always increased in all treatments, while the totals for n‐6 acids always decreased (p <0.05). For a given level of flaxseed oil, the LNA contents were consistently higher, including EPA (20:5n‐3) and DHA (22:6n‐3). Arachidonic acid (20:4n‐6) remained high in the PL but was reduced as levels of dietary flaxseed oil were increased. The n‐6/n‐3 ratios decreased significantly with the rise in flaxseed oil content in all treatments, and highly unsaturated fatty acid contents increased with the levels of flaxseed oil. Overall, the influence of flaxseed oil on the fatty acid composition in the contributing NL and PL classes was to increase n‐3 PUFA, thus raising the nutritional value of this freshwater fish meat and, consequently, contributing to the health of consumers.     

Studies on characterization and variation in triglyceride fatty acids from punt/us sarana body lipids

Body lipids of P. sarana of four different sizes were fractionated into phospholipids, neutral lipids, nonsaponifiables, total fatty acids, polyunsaturated, monounsaturated and saturated fatty acid fractions. Percentage composition of each fraction was determined. The triglyceride fatty acids were identified by thin layer and gas liquid chromatography. C₈ to C₂₃ fatty acids including both odd numbered and branched chain acids were detected. The major constituents were C₁₄, C₁₅, C₁₆, C_16:1, C₁₈ C_18:1, C_18:2, C_18:3; forty-three other acids were detected in lower proportions. Composition of each fatty acids and their variation with size have been discussed.tP. sarana body lipids in general showed a behavior typical of fresh water fish by having a higher percentage of saturated C₁₆ and unsaturated C₁₈ acids and a lower percentage of unsaturated C₂₀ acid.     

Wax esters and triglycerides as storage substances in seeds of Buxus sempervirens

The seeds of the evergreen Buxus‐tree, Buxus sempervirens, contain a yellowish oil which represents up to 42% of the dry weight. The oil consists, in comparison to the lipids of jojoba fruits (Simmondsia chinensis), of only 3.6% wax esters. 95% of the oil consist of triglycerides, the typical storage substances of oil fruits. Phospholipids occur with 0.4% and glycolipids with 0.13%. The fatty acid patterns of these lipids correspond to the typical fatty acid compositions of the respective lipid classes. In the wax esters monoenoic fatty acids and saturated fatty acids with 16 and 18 carbon atoms prevail. The glycolipid and phospholipid fractions are characterized by a high portion of dienoic and monoenoic as well as saturated fatty acids having 16 and 18 carbon acids.     

Neutral lipids of chickpea flour and protein isolates

The neutral lipids composition of defatted chickpea flour and two types of protein isolates has been studied. The main compounds in neutral lipids are triacylglycerols, free fatty acids, and diacylglycerols. Other compounds present are wax esters, free fatty alcohols, and free sterols. The main fatty acids in neutral lipids are C_18:2 and C_18:1 among the unsaturated, and C_16:0 and C_18:0 among the saturated acids. Free and esterified alcohols range from C_16:0 to C_28:0, the majority being those with an even number of carbon atoms. Sterols observed are β-sito-sterol, campesterol, stigmasterol, and δ-5-avenasterol. Triacyl-glycerols are partially hydrolyzed, and the amounts of unsaturated sterols and unsaturated fatty acids are reduced as a result of the chemical treatment during production of the protein isolates.     

Fatty acid composition of polar lipids in goats' milk

Silicic acid column chromatography was used to separate the polar lipids of goats' milk into glycolipid, phosphatidylethanolamine, phosphatidylserine plus phosphatidylinositol, phosphatidylcholine, and sphingomyelin fractions. Each fraction was purified by column chromatography and its fatty acid profile determined by gas liquid chromatography and mass spectrometry. The glycerophospholipids each contained 18∶1 as the predominant fatty acid (∼45%). The sphingolipids contained a high percentage of long-chain saturated fatty acids (C₂₂ to C₂₄>45%); the glycolipid fraction also contained ca. 2% 2-hydroxy fatty acids. The data represent a comprehensive cross-sectional study of the major polar lipids found in goats' milks.     

Fatty acid relationship in an aquatic food chain

The relationships amongst the fatty acids of the lipids from members of a model aquatic food chain were examined. The basic pattern of the fatty acids in the members, algae-brine shrimp-hydra, originated in the phytoplankton. Fatty acids in the neutral lipids of adult brine shrimp,Artemia salina, closely resembled dietary, or algal, fatty acids, whereas the phospholipid acids differed considerably from those in the algae. Fatty acids from the total lipids ofHydra pseudoligactis fed brine shimp nauplii also resembled the dietary acids, but more C₂₀ polyunsaturates and fewer C₁₈ unsaturated acids were present in those raised at 10C than were found at 20C.     

Varietal difference in lipid content and fatty acid composition of highbush blueberries

Lipids from five cultivars of highbush blueberries (Vaccinium corymbosum L.) were extracted and fractionated into neutral lipids (60–66%), glycolipids (20–22%) and phospholipids (14–18%). The major fatty acids in all fractions were palmitic (16∶0), oleic (18∶1), linoleic (18∶2), and linolenic (18∶3) acids. All lipid classes had a large concentration of C₁₈ polyunsaturated acids (84–92%), indicating that blueberries are a rich source of linoleic and linolenic acids. Changes in the fatty acid composition of neutral lipids and phospholipids were not significantly different among the five cultivars, but significant differences were noted in the ratios of linoleic and linolenic acids in the glycolipids fraction.     

Studies on lipid and fatty acid composition of human hepatoma tissue

Studies are reported on the composition of the lipids of human liver and hepatoma tissues from male adults. Liver tissues were obtained from individuals who died from causes other than liver disease or cancer. The hepatoma tissues were obtained from individuals shortly after they succumbed to cancer. The total lipid of each tissue was fractionated quantitatively by silicic acid column chromatography into neutral lipid, glycolipid, and phospholipid fractions. These fractions were analyzed by thin layer chromatography and converted to methyl esters for analysis of their constituent fatty acids by gas liquid chromatography. In comparison to liver tissue, the total amount of lipid in the hepatoma tissues was generally higher and more variable; the lipid of one hepatoma was ca. 92% of the dry wt of the tissue. The greater lipid content of the hepatoma tissues was due to the high percentage of neutral lipid. Except for one specimen, there was ca. the same amount of glycolipid in the hepatoma as in the liver tissues, but the composition of the glycolipid fraction of the hepatoma lipid differed considerably, particularly in the ganglioside fraction. The phospholipid fraction of hepatoma lipid was much lower than that of liver but exhibited only quantitative differences in composition. No glyceryl ether diesters and only traces of plasmalogens of phosphatidyl choline or phosphatidyl ethanolamine were detected in the liver and hepatoma lipids. The levels of monoenoic acids were higher and those of linoleic and polyunsaturated fatty acids lower in the hepatoma lipids. Positional isomers of trienoic acids not normally present in liver tissue were detected in hepatoma lipids. The abnormalities observed in lipid composition indicated interferences in the regulatory processes of lipid metabolism in human hepatoma similar to those observed in animals.     

A lipidomic approach for profiling and distinguishing seed oils of Hibiscus manihot L., flaxseed,and oil sunflower

As important oil crops in Inner Mongolia, sunflower, and flaxseed had distinct lipid profiles in seeds. As an emerging cash crop, Hibiscus manihot L. has strong potential market competitiveness. In this study, the lipidome, fatty acid composition and quality characteristics of flaxseed, H. manihot L., and sunflower seed oils were analyzed and compared. A total of 270 distinct lipids were identified and analyzed with an emerging detection approach—lipidomics, which illustrated the tremendous difference among the samples. triacylglycerol, diacylglycerol and polar lipids were the most abundant lipids in all samples. H. manihot L. seeds contained higher saturated and monounsaturated fatty acids and lower polyunsaturated fatty acids. H. manihot L. seed oil had the longest oxidative stability index time, high content of vitamin E and total phenolics, while flaxseed oil embodied the lowest oxidative stability. The peroxide value and acid value of the three oils were within the allowable range of Chinese national standards.     

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

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.     

Acetate and mevalonate labeling studies with developingCuphea lutea seeds

Cuphea seeds contain large amounts of medium chain (C₈ to C₁₄) fatty acids, mainly as triacylglycerols. The biosynthesis of these lipids was studied in vivo by incubating developingCuphea lutea seeds with labeled acetate. Incorporation of label into triacylglycerols and into medium chain fatty acids occurred principally during the period of endogenous lipid deposition, but some label was encountered in these products even during seed dehydration. At this later stage palmitate and oleate were the dominant labeled fatty acids. During the period of rapid endogenous lipid deposition acyl lipids other than triacylglycerols were minor labeled components. The labeling patterns were consistent with the Kennedy pathway for triacylglycerol biosynthesis. The fatty acid composition of the acyl-CoA pool was similar to the total lipid fatty acid composition, but the acyl-ACP pool contained relatively more short chain acyl groups. Squalene was labeled from acetate throughout the period of seed development, but labeled sterols were not detected. Using [2-¹⁴C]mevalonic acid lactone as substrate, squalene was the principal labeled product. Small amounts of label were found in free sterols. However, in terms of mass, free sterol dominated over squalene. The possibility of two independent sites of isoprenoid biosynthesis in the developing embryo is discussed.     

1-O-alkyl-2,3-diacylglycerols in the skin surface lipids of the hairless mouse

A neutral lipid class was isolated by thin-layer chromatography from the skin surface lipids of the hairless mouse. The fraction migrated faster than triglycerides and had a migration rate similar to that of diacyl alkanediols (diester wax). Upon deacylation, however, the long-chain diols were identified as 1-alkylglycerol ethers based on their chromatographic properties and on the mass spectra of their nicotinylidene derivatives. Thus, the skin lipid fraction was identified as 1-O-alkyl-diacylglycerol. The alkyl moieties were all saturated and even-numbered and ranged in chainlength from C₁₆ to C₂₂ with 1-O-hexadecylglycerol amounting to 34% of the total glycerol ether moieties. The fatty acids derived from this lipid fraction were mostly monoenoic with chainlengths ranging from C₁₆ to C₂₄. The major acyl component was eicosenoic acid (20∶1) representing 61% of the total fatty acids.     

Biochemical Studies on Whey Lipid Substances

The present work was undertaken to determine the lipid materials of salted and unsalted whey as a byproduct of cheese industry. The general chemical analysis show that the salted whey contained lower amounts of lactase, proteins and lipids compared with unsalted whey. Whey lipids contained palmitic and oleic acids as the most abundant saturated and unsaturated acids, respectively. The presence of salt quantitatively altered the concentration of short-chain fatty acids due to its salting out phenomenon. A wide variety of hydrocarbons was found and C₂₂, C₂₃ constituted over 75% of the total hydrocarbons. The presence of salt in whey remarkably changed the hydrocarbon profile. The most predominant phospholipid was phosphatidyl choline followed by phosphatidyl inositol. Once more, the salt changed qualitatively and quantitatively the whey phospholipid pattern and led to precipitate some of the highly polar phospholipids with cheese during milk processing.     

Wax esters in the cystacanths ofPolymorphus minutus (Acanthocephala)

The lipids of the cystacanth of the acanthocephalanPolymorphus minutus have been analyzed. Wax esters constituted nearly 90% of the total cystacanth lipids. The wax ester fraction contained approximately 10% steroid ester; the rest was long chain alcohols C₁₂ to C₂₀, largely saturated, esterified with fatty acids C₁₂ to C₂₂, mostly unsaturated, with C₁₈ predominating. Corresponding quantities of wax esters were not found in the adult parasite. Cholesterol was identified as the only steroid present in the cystacanth.     

Isovaleric acid as a precursor of odd numbered iso fatty acids in Tetrahymena

Tris isovalerate-supplementedTetrahymena pyriformis W showed no qualitative change in fatty acid composition; however, an increase in polar lipids that contain odd numbered iso acids (C₁₃, C₁₅, C₁₇, C₁₉) occurred. This change was accompanied by a decrease in the proportional amount of even numbered normal acids (C₁₄, C₁₆, C₁₈). The neutral and polar lipids from cells incubated with [1-¹⁴C] isovaleric acid were found to contain radioactivity. The methyl esters of the saturated fatty acids obtained from the polar lipids by alkaline methanolysis were separated by reversed phase chromatography, the identities confirmed by gas chromatography-mass spectrometry, and the specific activities determined. Iso acids were found to be the most heavily labeled materials. In addition to ceramide, two sphingolipid components were detected. One yielded saturated fatty acids after acidic methanolysis, while the other contained >93% α-hydroxy fatty acids. Radioactivity was noted in the long chain base fraction derived from the sphingolipids. Progressive growth inhibition occurred as the isovalerate concentration was increased in the culture medium; however, the ciliates were morphologically indistinguishable from unsupplemented cells.