Cyclopropene fatty acids in some Malaysian edible seeds and nuts: I. Durian (Durio zibethinus,Murr.)

The aril and seeds of the fruit Durian (Durio zibethinus, Murr.) were examined for their protein content and fatty acid composition by gas liquid chromatography (GLC). The values (area percentage) for fatty acids as methyl esters were: aril=14∶0 (0.91%); 16∶0 (34.13%); 16∶1 (7.10%); 18∶0 (1.21%); 18∶1 (42.14%); 18∶2 (7.85%) and 18∶3 plus 20∶0 (5.69%), Seeds=14∶0 (0.12%); 16∶0 (12.20%); 16∶1 (1.15%); 18∶0 (1.42%); 18∶1 (8.42%); 18∶2 (6.50%); dihydrosterculic acid (2.52%); 18∶3 plus 20∶0 (11.30%); malvalic acid (15.72%); sterculic acid (38.53%) and 22∶0 (1.21%). The germ oil contained the highest amount of sterculic acid. The cooking temperatures employed reduced the malvalic and sterculic acid contents in seeds only by ca. 22% and 19%, respectively.     

Fatty chain compositon of ether and ester glycerophospholipids in the Japanese oysterCrassostrea gigas (Thunberg)

The fatty chain compositions of 1-O-alk-1′-enyl-2-acyl, 1-0-alkyl-2-acyl, and 1,2-diacyl glycerophospholipids of the Japanese oysterCrassostrea gigas (Thunberg) were investigated. Major fatty chains in thesn-1 position of 1-alk-1′-enyl-2-acyl ethanolamine phospholipids (EPL) were 18∶0 (64.7%) and 20∶1 (11.1%). Majorsn-1 chains of alkenylacyl choline phospholipids (CPL) were 18∶0 (63.3%) and 16∶0 (22.2%). In the case of 1-alkyl-2-acyl EPL, the predominant fatty chains in thesn-1 position were 18∶0 (51.5%), 16∶0 (16.0%) and 20∶1 (12.5%); in the case of 1-alkyl-2-acyl CPL, the majorsn-1 chains were 16∶0 (44.0%) and 14∶0 (23.4%). Saturated fatty chains were predominant in both EPL and CPL. Prominent fatty acids in thesn-2 position of the alkenylacyl EPL were 22∶6n−3 (29.0%), 20∶5n−3 (19.0%) and 22∶2 NMID (non-methylene interrupted dienes, 16.6%) contributing to about 65% of the total fatty acids, while alkenylacyl CPL was rich in the saturated acids 16∶0 (32.0%) and 18∶0 (9.2%). In the alkylacyl EPL, 16∶0, 18∶1n−9, 18∶0 and 16∶1n−7 were prominentsn-2 fatty acids and accounted for 30.6%, 10.0%, 9.8%, and 8.3%, respectively. Polyunsaturated fatty acids were detected, but were present at extremely low percentages. Majorsn-2 fatty acids in alkylacyl CPL were 16∶0 (25.4%), 22∶6n−3 (16.0%) and 20∶5n−3 (8.4%). The major fatty acids of diacyl EPL were 20∶5n−3 (22.3%), 16∶0 (17.9%), and 18∶0 (16.1%), and those of diacyl CPL were 16∶0 (30.4%), 20∶5n−3 (17.6%) and 18∶1n−7 (7.4%).     

Dietary linoleic acid and the fatty acid profiles in rats fed partially hydrogenated marine oils

The influence of the linoleic acid levels of diets containing partially hydrogenated marine, oils (HMO) rich in isomeric 16∶1, 18∶1, 20∶1 and 22∶1 fatty acids on the fatty acid profiles of lipids from rat liver, heart and adipose tissue was examined. Five groups of rats were fed diets containing 20 wt% fat−16% HMO+4% vegetable oils. In these diets, the linoleic acid contents varied between 1.9% and 14.5% of the dietary fatty acids, whereas the contents oftrans fatty acids were 33% in all groups. A sixth group was fed a partially hydrogenated soybean oil (HSOY) diet containing 8% linoleic acid plus 32%trans fatty acids, mainly 18∶1, and a seventh group, 20% palm oil (PALM), with 10% linoleic acid and notrans fatty acids. As the level of linoleic acid in the HMO diets increased from 1.9% to 8.2%, the contents of (n−6) polyunsaturated fatty acids (PUFA) in the phospholipids increased correspondingly. At this dietary level of linoleic acid, a plateau in (n−6) PUFA was reached that was not affected by further increase in dietary 18∶2(n−6) up to 14.5%. Compared with the HSOY- or PALM-fed rats, the plateau value of 20∶4(n−6) were considerably lower and the contents of 18∶2(n−6) higher in liver phosphatidylcholines (PC) and heart PC. Heart phosphatidylethanolamines (PE) on the contrary, had elevated contents of 20∶4(n−6), but decreased 22∶5(n−6) compared with the PALM group. All groups fed HMO had similar contents oftrans fatty acids, mainly 16∶1 and 18∶1, in their phospholipids, irrespective of the dietary 18∶2 levels, and these contents were lower than in the HSOY group. High levels of linoleic acid consistently found in triglycerides of liver, heart and adipose tissue of rats fed HMO indicated that feeding HMO resulted in a reduction of the conversion of linoleic acid into long chain PUFA that could not be overcome by increasing the dietary level of linoleic acid.     

Dihydrosterculic acid,a major fatty acid component ofEuphoria longana seed oil

The seed oil ofEuphoria longana, Sapindaceae, contains 17.4% of 9,10-methyleneoctadecanoic (dihydrosterculic) acid. This identification is based on information from thin layer chromatography, infrared analysis, gas liquid chromatography, nuclear magnetic resonance and mass spectroscopy. Since GLC of the oil showed components that emerged between the usual triglycerides, the cyclopropanoid acid is apparently a triglyceride constituent. The presence of smaller amounts, less than 1%, of cyclopropanoid fatty acids of different chain lengths is indicated by GLC and TLC analyses of the methyl esters. The other major fatty acids in this oil are: 16∶0 (19%), 18∶0 (7%), 18∶1 (36%), 18∶2 (6%), 18∶3 (5%) and 20∶0 (4%).Euphoria oil contains considerably larger amounts of cyclopropanoid fatty acids than previously reported in other seed oils. Presented at the AOCS-AACC Joint Meeting, Washington, D.C., April 1968. No. Utiliz. Res. Dev. Div.; ARS, USDA.     

Characterization and oxidative stability of enzymatically produced fish and canola oil-based structured lipids

Two-kilogram quantities of structured lipids (SL) of menhaden fish and canola oils containing caprylic acids (8∶0) were produced in a laboratory-scale packed-bed bioreactor by acidolysis catalyzed by an immobilized lipase, Lipozyme IM, from Rhizomucor miehei. SL were characterized and their oxidative stabilities investigated. The SL contained 29.5% 8∶0 for fish oil and 40.15 for canola oil. Polyunsaturated fatty acids (PUFA) of fish oil remained unchanged after the modification while PUFA of canola oil were reduced from 29.6 to 21.2%. Monoenes, especially 18∶1n−9, were completely replaced by 8∶0 in fish oil and reduced from 61.9 to 34.7% in canola oil. Downstream processing of enzymatically produced SL led to loss in natural total tocopherol contents of the fish and canola oils. The effects of antioxidants such as α-tocopherol (TOC), tert-butylhydroxyquinone (TBHQ), and combinations thereof on the oxidative stability of SL were investigated. SL were analyzed for oxidative stability index, peroxide value, conjugated diene content, free fatty acid content, iodine value, saponification number, and thiobarbituric acid value. Iodine value of unmodified fish oil (154.71) was reduced to 144.10 and that of canola oil (114.49) to 97.27 after modification. The SN increased from 183.72 to 242.63 for fish oil and from 172.50 to 227.90 for canola oil. TBHQ exhibited better antioxidant effects than TOC. A combination of TBHQ/TOC also proved to be an effective antioxidant for SL. We suggest the addition of antioxidants to enzymatically produced and purified SL.     

Fatty acid composition of subcellular particles from sheep platelets and topological distribution of phosphatidylethanolamine fatty acids in the plasma membrane

The fatty acid composition of individual phospholipids in subcellular fractions of sheep platelets and the asymmetrical distribution of phosphatidylethanolamine (PE) fatty acyl chains across the plasma membrane were examined. The main fatty acids of total lipid extracts were oleic (18∶1; 32–41%), linoleic (18∶2, 10–17%), stearic (18∶0; 13–15%), palmitic (16∶0; 11–15%) and arachidonic (20∶4; 8–12%) acids, with a saturated/unsaturated ratio of about 0.4. Each phospholipid class had a distinct fatty acid pattern. Sphingomyelin (SM) showed the highest degree of saturation (50%), with large proportions of behenic (22∶0), 18∶0 and 16∶0 acids. The main fatty acid in PE, phosphatidylserine (PS) and phosphatidylcholine (PC) was 18∶1n−9. Our findings suggest that fatty acids are asymmetrically distributed between thecholineversus the non-choline phospholipids, and also between plasma membranes and intracellular membranes. The transbilayer distribution of PE fatty acids in plasma membranes from non-stimulated sheep platelets was investigated using trinitrobenzenesulfonic acid (TNBS). A significant degree of asymmetry was found, which is a new observation in a non-polar cell. The PE molecules from the inner monolayer contained higher amounts of 18∶2 and significantly less 18∶1 and 20∶5 than those found in the outer monolayer, although no major differences were detected in the transbilayer distribution of total unsaturatedversus saturated PE acyl chains.     

Lipids and fatty acids of the horseshoe crabsTachypleus gigas andCarcinoscorpius rotundicauda

Total lipids from hepatopancreas of the horseshoe crabs,Tachypleus gigas andCarcinoscorpius rotundicauda, obtained in 7.6 and 3.3% wet weight respective yields, were fractionated by various chromatographic techniques and identified by gas-liquid chromatography and spectroscopic methods. Fatty acid-containing lipids were rich in 16∶0 (8.0–25%), 18∶1ω9 (6.9–22%) and 18∶2ω6 (6.8–18.5%); appreciable amounts of 16∶1ω7, 18∶3ω3, 20∶5ω3 and 22∶6ω3 were also present. The level of 26∶0 in the hydrocarbon fractions was unusually high (64 and 68%). Carbon chain lengths of major wax esters were 44, 46 and 48 forT. gigas and 38, 40 and 42 forC. rotundicauda. 1-O-Alkyl diglycerides were 7.2 and 9.1% of the total lipids in the two species and contained 14∶0(20%), 16∶0(60%) and 18∶0(20%) alkyl chains along with a relatively higher percentage (32–35%) of saturated fatty acids. High levels of cholesterol (>50% of total sterol) in the free and combined state were encountered in both samples, phospholipid contents being 40 and 35%, respectively, and contained highest levels of unsaturated fatty acids.     

Influence of dietary fat composition on intestinal absorption in the rat

Omega-3 fatty acids influence the function of the intestinal brush border membrane. For example, the omega-3 fatty acid eicosapentaenoic acid (20∶5ω3) has an antiabsorptive effect on jejunal uptake of glucose. This study was undertaken to determine whether the effect of feeding α-linolenic acid (18∶3ω3) or EPA plus docosahexaenoic acid (22∶6ω3) on intestinal absorption of nutrients was influenced by the major source of dietary lipid, hydrogenated beef tallow or safflower oil. Thein vitro intestinal uptake of glucose, fatty acids and cholesterol was examined in rats fed isocaloric diets for 2 weeks: beef tallow, beef tallow + linolenic acid, beef tallow + eicosapentaenoic acid/docosahexaenoic acid, safflower oil, safflower oil + linolenic acid, or safflower oil + eicosapentaenic acid/docosahexaenoic acid. Eicosapentaenoic acid/docosahexaenoic acid reduced jejunal uptake of 10 and 20 mM glucose only when fed with beef tallow, and not when fed with safflower oil. Linolenic acid had no effect on glucose uptake, regardless of whether it was fed with beef tallow or safflower oil. The jejunal uptake a long-chain fatty acids (18∶0, 18∶2ω6, 18∶3ω3, 20∶4ω6, 20∶5ω3 and 22∶6ω3) and cholesterol was lower in salfflower oil than with beef tallow. When eicosapentaenoic acid/docosahexaenoic acid was given with beef tallow (but not with safflower oil), there was lower uptake of 18∶0, 20∶5ω3 and cholesterol. The demonstration of the inhibitory effect of linolenic acid or eicosapentaenoic acid/docosahexaenoic acid on cholesterol uptake required the feeding of a saturated fatty acid diet (beef tallow). These changes in uptake were not explained by differences in the animals’ food intake, body weight gain or intestinal weight. Feeding safflower oil was associated with an approximately 25% increase in the jejunal and ileal mucosal surface area, but this increase was prevented by combining linolenic acid or eicosapentaenoic acid/docosahexaenoic acid with safflower oil. Different inhibitory patterns were observed when mixtures of fatty acids were present together in the incubation medium, rather than in the diet: for example, when 18∶0 was in the incubation medium with 20∶4ω6, the uptake of 20∶4ω6 was reduced, whereas the uptake was unaffected by 18∶2ω6 or 20∶5ω3. Thus, (1) the inhibitory effect of eicosapentaenoic acid/docosahexaenoic acid on jejunal uptake of glucose, fatty acids and cholesterol was influenced by the major dietary lipid, saturated (beef tallow) or polyunsaturated fatty acid (safflower oil); and (2) different omega-3 fatty acids (linolenic acid versus eicosapentaenoic acid/docosahexaenoic acid) have a variable influence on the intestinal absorption of nutrients.     

Oil content and fatty acid composition of commercially important Turkish fish species

The oil content and fatty acid composition of commercially important Turkish fish species (anchovy,Engraulis encrasicholus; freshwater rainbow trout,Salmo gairdneri; and cultured salmon,S. salar) were determined. Palmitic (16∶0), palmitoleic (16∶1), oleic (18∶1), and docosahexaenoic (22∶6) acids were the most abundant fatty acids in all species. Eicosapentaenoic acid (20∶5) was twice as high in the anchovy oil as in the rainbow trout and salmon oils. Significant quantities of linoleic acid (18∶2) and docosahexaenoic acids (22∶6) were found in both rainbow trout and salmon samples. The individual fatty acid data obtained from rainbow trout and salmon were similar to each other. All three fish species contain high levels of n-3 polyunsaturated fatty acids and would be suitable for inclusion in the formulation of low-fat highly unsaturated diets.     

Reduction in medium chain acids and monoenoic acids in livers and plasma of rats fed eicosa-5,8,11,14-tetraynoic acid

Male Sprague-Dawley rats were fed for 8 weeks a corn oil (CO) diet or a hydrogenated coconut oil (HCNO) diet. These diets were fed in the absence or presence of eicosa-5,8,11,14-tetraynoic acid (TYA). The inclusion of TYA in the HCNO diet reduced the levels of 12∶0 and 14∶0 in the total fatty acids of livers and plasma. With either diet, the presence of TYA caused an alteration in the fatty acid composition of these tissues so as to reduce the values of the ratios: 16∶1/16∶0, 18∶1/18∶0, and 20∶4/18∶2. These results suggest that dietary TYA can influence the hepatic metabolism of medium chain fatty acids and that it may inhibit the desaturase enzyme involved in the synthesis of not only 20∶4 but also of monoenoic fatty acids.     

trans fatty acids. 4. Effects on fatty acid composition of colostrum and milk

trans Isometric fatty acids of partially hydrogenated fish oil (PHFO) consist oftrans 20∶1 andtrans 22∶1 in addition to thetrans isomers of 18∶1, which are abundant in hydrogenated vegetable oils, such as in partially hydrogenated soybean oil (PHSBO). The effects of dietarytrans fatty acids in PHFO and PHSBO on the fatty acid composition of milk were studied at 0 (colostrum) and 21 dayspostpartum in sows. The dietary fats were PHFO (28%trans), or PHSBO (36%trans) and lard. Sunflower seed oil (4%) was added to each diet. The fats were fed from three weeks of age throughout the lactation period of Experiment 1. In Experiment 2 PHFO or “fully” hydrogenated fish oil (HFO) (19%trans), in comparison with coconut oil (CF) (0%trans), was fed with two levels of dietary linoleic acid, 1 and 2.7% from conception throughout the lactation period. Feedingtrans-containing fats led to secretion oftrans fatty acids in the milk lipids. Levels oftrans 18∶1 andtrans 20∶1 in milk lipids, as percentages of totalcis+trans 18∶1 andcis+trans 20∶1, respectively, were about 60% of that of the dietary fats, with no significant differences between PHFO and PHSBO. The levels were similar for colostrum and milk. Feeding HFO gave relatively lesstrans 18∶1 andtrans 20∶1 fatty acids in milk lipids than did PHFO and PHSBO. Only low levels ofcis+trans 22∶1 were found in milk lipids. Feedingtrans-containing fat had no consistent effects on the level of polyenoic fatty acids but reduced the level of saturated fatty acids and increased the level ofcis+trans monoenoic fatty acids. Increasing the dietary level of linoleic acid had no effect on the secretion oftrans fatty acids but increased the level of linoleic acid in milk. The overall conclusion was that the effect of dietary fats containingtrans fatty acids on the fat content and the fatty acid composition of colostrum and milk in sows were moderate to minor.     

Influence of dietary linoleic acid andtrans fatty acids on the fatty acid profile of cardiolipins in rats

Cardiolipins (CL) have unique fatty acid profiles with generally high levels of polyunsaturated fatty acids, primarily 18∶2n−6, and low levels of saturated fatty acids. In order to study the effect of dietary fatty acid isomers on the fatty acid composition of cardiolipins, rats were fed partially hydrogenated marine oils (HMO), rich in 16∶1, 18∶1, 20∶1, and 22∶1 isomeric fatty acids, supplemented with linoleic acid at levels ranging from 1.9% to 14.5% of total fat. Although the dietary fats contained 33%trans fatty acids, the levels oftrans fatty acids in CL were below 2.5% in all organs. The fatty acid profiles of cardiolipins of liver, heart, kidney and testes showed different responses to dietary linoleic acid level. In liver, the contents of 18∶2 reflected the dietary levels. In heart and kidney, the levels of 18∶2 also parallelled increasing dietary levels, but in all groups fed HMO, levels of 18∶2 were considerably higher than in the reference group fed palm oil. In testes, the 18∶2 levels were unaffected by the dietary level of 18∶2 and HMO.     

Phospholipid composition of the granular amebocyte from the horseshoe crab, Limulus polyphemus

The phospholipid composition was determined for the amebocyte of the primitive arthropod Limulus polyphemus. The total fatty acid composition of the cells' lipids was analyzed by gas chromatography/mass spectrometry (GC/MS) of fatty acid methyl esters (FAME). The FAME analysis revealed high levels of 20-carbon polyunsaturated fatty acids (PUFA), especially arachidonic (20∶4n-6) and eicosapentaenoic (20∶5n-3) acids. Almost 20% of the total lipid profile was comprised of dimethyl acetals of 16- to 20-carbon chain lengths, indicative of plasmalogens in the phospholipid pool. Phospholipids, analyzed by high-pressure liquid chromatography, included phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI), sphingomyelin (SPH), and cardiolipin (CL). PE and PC levels predominated at 42.2 and 36.3%, respectively. Smaller amounts of PS (9.0%) and PI (6.2%) were present, as well as low levels of SPH (4.6%), CL (1.6%), and trace amounts of lysophosphatidylcholine. The major phospholipid species, PE, PC, PS and PI, were collected and their molecular species were examined by electrospray-ionization mass spectrometry. The molecular species within the phospholipid classes reflected the high levels of PUFA seen in the total lipid profile. PI was mainly composed of 18∶0a/20∶4. Over half of the PS consisted of 18∶0a/18∶1 and 18∶0a/20∶4. The major PE species were 20∶1p/20∶5, 20∶1p/20∶4, 18∶0p/20∶5, and 18∶0p/20∶4. PC had the largest distribution of molecular species, and its most abundant species were 16∶0e/20∶5, 16∶0e/20∶4, and 16∶0p/20∶4. The presence of 16∶0e/20∶4 is the first documentation of a specific precursor to platelet-activating factor in an invertebrate hemocyte. Note: at the sn-1 position: [a=1=O-acyl, e=1-O-alkylether, and p=1-O-alk-1′-enyl (plasmalogen)].     

Dietary saturated,monounsaturated, n−6 and n−3 fatty acids,and cholesterol influence platelet fatty acids in the exclusively formula-fed piglet

Platelet lipid composition is important to normal platelet morphology and function, and is influenced by dietary fatty acids and cholesterol. The fatty acid composition and cholesterol content of infant formulas differs from those of human milk, but the possible effects on platelet lipids in young infants is not known. This was studied in piglets fed from birth to 18 d of age with one of eight formulas differing in saturated fatty acid chain length, or content of 18∶1, 20∶5n−3 plus 22∶6n−3, or cholesterol. A reference group of piglets fed sow milk was also studied. Sow milk has a fatty acid composition and cholesterol content similar to that of human milk. Piglets fed formulas high in 18∶1 (34.9–40.8% wt fatty acids) and low in 16.0 (≤6.5% wt fatty acids) had lower platelet counts and greater platelet size than piglets fed sow milk (40.4% 18∶1, 30.7% 16∶0). Piglets fed formulas high in 16∶0 (27–29.6%) and 18∶1 (40–40.6%), or low in both 16∶0 (5.9–6.1%) and 18∶1 (10.8–11.2%), had similar platelet counts and size to piglets fed sow milk. Platelet phospholipid % 20∶4n−6 was lower in all the groups of piglets fed formula than in the group fed sow milk. Addition of fish oil with 20∶5n−3 plus 22∶6n−3 to the formula further decreased platelet phospholipid 20∶4n−6. Addition of cholesterol to the formula increased the platelet phospholipid % 20∶4n−6 and platelet volume.     

A diet containing myristoleic plus palmitoleic acids elevates plasma cholesterol in young growing swine

The objective of this study was to test the effect of a novel fatty acid mixture, enriched with myristoleic and palmitoleic acids, on plasma lipoprotein cholesterol concentrations. Weanling pigs were assigned to one of six groups and each group received a diet differing in fatty acid composition. Diets were fed for 35 days and contained 10 g added cornstarch/100 g (to provide baseline data) or 10 g added fatty acids/100 g. For those diets containing added fatty acids, extracted lipids contained 36% myristoleic plus palmitoleic acid combined (14∶1/16∶1 diet), 52% palmitic acid (16∶0 diet), 51% stearic acid (18∶0 diet), 47% oleic acid (18∶1 diet), or 38% linoleic acid (18∶2 diet). Witht the exception of the cornstarch diet, all diets contained approximately 30% myristic acid. There were no significant differences in weight gain across treatment groups (P=0.22). All diets caused a significant increase in triglycerides and in total, low density lipoprotein, high density lipoprotein, and very low density lipoprotein cholesterol. The increase in total plasma cholesterol from pretreatment values was greatest in pigs fed the 14∶1/16∶1 and 18∶1 diets. However, the increase in low density lipoprotein cholesterol from the pretreatment concentration was greatest in the 14∶1/16∶1-fed pigs. Increases in very low density lipoprotein cholesterol above pretreatment concentrations were lowest in 16∶0-fed pigs and greatest in 18∶1-fed pigs. Dietary fatty acids elicited changes in plasma fatty acids which generally were reflective of the diets, although the 18∶0 diet did not alter plasma fatty acid concentrations and the 16∶0 diet increased plasma 16∶0 only at the end of the study. These results demonstrated that the combination of myristoleic plus palmitoleic acids increased plasma cholesterol in young pigs, suggesting that fatty acid chain length, rather than degree of unsaturation, is primarily responsible for the effects of fatty acids on circulating lipoprotein cholesterol concentrations.     

The fatty acids ofEntomophthora coronata

The total lipids and fatty acid composition ofEntomophthora coronata were determined. The fungus was grown on a chemically defined medium and a chemically nondefined medium (Sabouraud dextrose yeast extract) for a period of 26 days. The organism contained from 16.2% to 44.6% total lipids depending upon the days of growth. The major fatty acids were 12∶0 (5.5–9.0%), 13∶0 (1.2–8.2%), 14∶0 (33.5–43.5%), 16∶0 (9.7–13.9%), 18∶1₉ (20.4–22.4%), and 18∶2_9,12 (3.5–10.5%). Lesser amounts of 15∶0, 16∶1, 16∶2, 17∶0, 18∶0, two other 18∶2 (both having conjugated double bonds), 18∶3_6,9,12, another 18∶3 (conjugated double bonds), 20∶3_8,11,14, 20∶4_5,8,11,14, another 20∶4 (conjugated double bonds), and 24∶1 acids were found. Trace amounts of 20∶0, 20∶1, 20∶2, 22∶0 and 24∶0 were also present. The relative percentage of most of the fatty acids did not vary appreciably with growth. However, 18∶2_9,12 and 20∶4_5,8,11,14 increased with age of the chemically defined culture. Peak E (18∶2, conjugated double bonds) increased and 13∶0 and 18∶3_6,9,12 decreased with age of the chemically nondefined culture. The fatty acids were predominately saturated (56.9–69.1%) and contained a high percentage of shorter chain fatty acids (C 12 to C 15). The fatty acids of the chemically defined culture were more unsaturated than the Sabouraud culture and the unsaturation increased with age of the culture.     

Pathways for fatty acid elongation and desaturation in Neurospora crassa

Neurospora crassa incorporated exogenous deuterated palmitate (16∶0) and ¹⁴C-labeled oleate (18∶1^Δ9) into cell lipids. Of the exogenous 18∶1^Δ9 incorporated, 59% was desaturated to 18∶2^Δ9,12 and 18∶3^Δ9,12,15. Of the exogenous 16∶0 incorporated, 20% was elongated to 18∶0, while 37% was elongated and desaturated into 18∶1^Δ9, 18∶2^Δ9,12, and 18∶3^Δ9,12,15. The mass of unsaturated fatty acids in phospholipid and triacylglycerol is 12 times greater than the mass of 18∶0. Deuterium label incorporation in unsaturated fatty acids is only twofold greater than in 18∶0, indicating a sixfold preferential use of 16∶0 for saturated fatty acid synthesis. These results indicate that the release of 16∶0 from fatty acid synthase is a key control point that influences fatty acid composition in Neurospora.     

Serum cholesterol predictive equations with special emphasis on trans and saturated fatty acids. an analysis from designed controlled studies

The effects of dietary trans fatty acids on serum total and low density lipoprotein (LDL) cholesterol have been evaluated by incorporating trans fatty acids into predictive equations and comparing their effects with the effects of the individual saturated fatty acids 12∶0, 14∶0, and 16∶0. Trans fatty acids from partially hydrogenated soybean oil (TRANS V) and fish oil (TRANS F) were included in previously published equations by constrained regression analysis, allowing slight adjustments of existing coefficients. Prior knowledge about the signs and ordering of the regression coefficients was explicitly incorporated into the regression modeling by adding lower and upper bounds to the coefficients. The amounts of oleic acid (18∶1) and polyunsaturated fatty acids (18∶2, 18∶3) were not sufficiently varied in the studies, and the respective regression coefficients were therefore set equal to those found by Yu et al. [Yu, S., Derr, J., Etherton, T.D., and Kris-Etherton, P.M. (1995) Plasma Cholesterol-Predictive Equations Demonstrate That Stearic Acid Is Neutral and Monounsaturated Fatty Acids Are Hypocholesterolemic, Am. J. Clin. Nutr. 61, 1129–1139]. Stearic acid (18∶0), considered to be neutral, was not included in the equations. The regression analyses were based on results from four controlled dietary studies with a total of 95 participants and including 10 diets differing in fatty acid composition and with 30–38% of energy (E%) as fat. The analyses resulted in the following equations, where the change in cholesterol is expressed in mmol/L and the change in intake of fatty acids is expressed in E%: Δ Total cholesterol=0.01 Δ(12∶0)+0.12 Δ(14∶0)+0.057 Δ(16∶0)+0.039 Δ(TRANS F)+0.031 Δ(TRANS V)−0.0044 Δ(18∶1)−0.017 Δ(18∶2, 18∶3) and ΔLDL cholesterol =0.01 Δ(12∶0)+0.071 Δ(14∶0)+0.047 Δ(16∶0)+0.043 Δ(TRANS F)+0.025 Δ(TRANS V)−0.0044 Δ(18∶1)−0.017 Δ(18∶2, 18∶3). The regression analyses confirm previous findings that 14∶0 is the most hypercholesterolemic fatty acid and indicate that trans fatty acids are less hypercholesterolemic than the saturated fatty acids 14∶0 and 16∶0. TRANS F may be slightly more hypercholesterolemic than TRANS V or there may be other hypercholesterolemic fatty acids in partially hydrogenated fish oil than those included in the equations. The test set used for validation consisted of 22 data points from seven recently published dietary studies. The equation for total cholesterol showed good prediction ability with a correlation coefficient of 0.981 between observed and predicted values. The equation has been used by the Norwegian food industry in reformulating margarines into more healthful products with reduced content of cholesterol-raising fatty acids. These authors have contributed equally to this work.     

Wax esters of barracudina lipid: A potential replacement for sperm whale oil

A sample of barracudina, a small fish potentially available in large quantities off Nova Scotia, contained 17.7% body lipid of which 10% was triglyceride and 85% wax ester. The triglyceride, of calculated iodine value 48, was unusually rich in 14:0 (25.8%), 18:0 (4.3%), 20:0 (1.19%), 22:0 (0.45%) and 24:0 (0.75%). The wax ester fatty acids had a calculated iodine value of 126 and a “normal” marine oil fatty acid composition. The wax ester fatty alcohols contained 42.2% hexadecanol, 29.5% octadecenols, 8.2% eicosenols and 3.8% docosenols. Certain interrelationships between fatty alcohols and fatty acids are indicated by details of composition. The potential exploitation of barracudina lipid as a substitute for sperm oil in some uses appears possible.     

Fatty acid and positional selectivities of gastric lipase from premature human infants:in vitro studies

Gastric lipase activity in aspirates from premature human infants was tested for fatty acid and positional selectivity using racemic diacid triacylglycerols (TG) as substrates. The resulting free fatty acids and monoacylglycerols (MG) were recovered and analyzed. Octanoic acid (8∶0) and decanoic acid (10∶0) were hydrolyzed with a preference of 61.5∶1 and 2.4∶1 compared to palmitic acid (16∶0) fromrac-16∶0–8∶8∶0 andrac-16∶0–10∶0–10∶0, respectively. The ratio of lauric acid (12∶0) to oleic acid (18∶1) hydrolyzed fromrac-18∶1–12∶0 was 13∶1. Myristic acid (14∶0), 18∶1 and linoleic acid (18∶2) were released at similar rates. These data and the composition of the MG suggest that,in vitro, the lipase is selective for shorter chain fatty acids and for fatty acids on the primary positions of the TG backbone.