The impact of dietary mono‐ and poly‐unsaturated fatty acids on risk factors for atherosclerosis in humans

The fatty acid composition of the diet has various effects on atherosclerosis risk factors. Dietary saturated fatty acids (SFA) and trans‐unsaturated fatty acids increase the low‐density lipoprotein (LDL)‐/high‐density lipoprotein (HDL)‐cholesterol ratio in serum, while these fats do not have a significant bearing on serum triglyceride levels. By contrast, dietary monounsaturated fatty acids (MUFA), n‐6 polyunsaturated fatty acids (PUFA), and α‐linolenic acid (C18:3n‐3) similarly reduce LDL cholesterol concentrations, while their influence on serum HDL cholesterol and triglycerides is not appreciable. Dietary long‐chain n‐3 PUFA slightly increase serum LDL cholesterol concentrations, but are nevertheless considered salubrious with regard to serum lipids due to the distinct triglyceride‐lowering effects. MUFA‐rich compared to n‐6 PUFA‐rich diets strongly reduce the in vitro oxidizability of LDL. The available studies on this subject also suggest that n‐3 PUFA in the small amounts usually present in the diet are not unduly harmful. These findings are consistent with reports from observational studies: the amount of SFA is positively and the amount of MUFA and n‐6 PUFA in the diet is inversely associated with the risk of cardiovascular disease in most epidemiological studies. The available studies have had an impact on current dietary guidelines, which unanimously recommend that most of the dietary fat should be in the form of MUFA, while the amount of SFA and trans fatty acids in the diet should be as low as possible.     

Short Chain Saturated Fatty Acids Decrease Circulating Cholesterol and Increase Tissue PUFA Content in the Rat

This study investigates the effect of various dietary saturated fatty acid (SFA) profiles on plasma lipid parameters and tissue fatty acid composition in rats. The experiment was designed to monitor polyunsaturated fatty acids (PUFA) levels, while examining different amounts and types of SFA. Four isocaloric diets were prepared, containing 10–11 mol% of fatty acids (FA) as linoleic acid (LNA) and 2.5 mol% as α-linolenic acid (ALA), leading to an identical and well-balanced LNA/ALA ratio. The initial rapeseed oil/corn oil mixture providing ALA and LNA was enriched with olive oil to prepare the olive oil diet. The butterfat diet was supplemented with butterfat, containing short-chain SFA (C4:0–C10:0, 17 mol% of FA), lauric acid (C12:0, 3.2 mol%), myristic acid (C14:0, 10.5 mol%) and palmitic acid (C16:0, 14.5 mol%). The saturates diet was supplemented with trilaurin, trimyristin and tripalmitin to obtain the same level of lauric, myristic and palmitic acids as the butterfat diet, without the short-chain SFA. The trimyristin diet was enriched with trimyristin only. The results showed that the butterfat diet contributed to specific effects, compared to the olive oil diet and the saturates and trimyristin diets: a decrease in plasma total, LDL- and HDL-cholesterol, higher tissue storage of ALA and LNA, and a higher level of (n-3) highly unsaturated fatty acids in some tissues. This study supports the hypothesis that in diets with identical well-balanced LNA/ALA ratios, short chain SFA may decrease circulating cholesterol and increase tissue polyunsaturated fatty acid content in the rat.     

An increase in dietary n-3 fatty acids decreases a marker of bone resorption in humans

Human, animal, and in vitro research indicates a beneficial effect of appropriate amounts of omega-3 (n-3) polyunsaturated fatty acids (PUFA) on bone health. This is the first controlled feeding study in humans to evaluate the effect of dietary plant-derived n-3 PUFA on bone turnover, assessed by serum concentrations of N-telopeptides (NTx) and bone-specific alkaline phosphatase (BSAP). Subjects (n = 23) consumed each diet for 6 weeks in a randomized, 3-period crossover design: 1) Average American Diet (AAD; [34% total fat, 13% saturated fatty acids (SFA), 13% monounsaturated fatty acids (MUFA), 9% PUFA (7.7% LA, 0.8% ALA)]), 2) Linoleic Acid Diet (LA; [37% total fat, 9% SFA, 12% MUFA, 16% PUFA (12.6% LA, 3.6% ALA)]), and 3) α-Linolenic Acid Diet (ALA; [38% total fat, 8% SFA, 12% MUFA, 17% PUFA (10.5% LA, 6.5% ALA)]). Walnuts and flaxseed oil were the predominant sources of ALA. NTx levels were significantly lower following the ALA diet (13.20 ± 1.21 nM BCE), relative to the AAD (15.59 ± 1.21 nM BCE) (p < 0.05). Mean NTx level following the LA diet was 13.80 ± 1.21 nM BCE. There was no change in levels of BSAP across the three diets. Concentrations of NTx were positively correlated with the pro-inflammatory cytokine TNFα for all three diets. The results indicate that plant sources of dietary n-3 PUFA may have a protective effect on bone metabolism via a decrease in bone resorption in the presence of consistent levels of bone formation.     

Stability of Cold-Pressed Oil from Commercial Indian Niger (Guizotia abyssinica (L.f.) Cass.) Seed as affected by Blending and Interesterification

Blending and interesterification of cold‐pressed oil from commercially available niger (Guizotia abyssinica (L.f.) Cass.) seeds was performed to improve its stability. The fatty acid composition of cold‐pressed niger seed oil (NSO) revealed that it contained a huge amount of polyunsaturated linoleic acid (69.2 %). NSO being rich in polyunsaturated fatty acids (PUFA) was susceptible to oxidation and hence was blended with saturated fatty acid (SFA) rich coconut oil (CNO) and monounsaturated fatty acid (MUFA) rich olive–pomace oil (OO) to enhance its stability. CNO contained a total of 91.3 % of SFA, while OO had oleic acid, C18:1 (74.3 %) as MUFA. Two blends of NSO with CNO and OO, i.e. NSO + CNO(B) and NSO + OO(B), were prepared in the ratio of 1:1. The blends were further interesterified using the lipase enzyme from Rhizomucor meihei and interesterified oils, i.e. NSO + CNO(I) and NSO + OO(I), were obtained. The oxidative stability of the oils was evaluated by incubating them at 37 °C and 55 % relative humidity (RH) for a period of 45 days. The peroxide values of NSO + CNO(B), NSO + OO(B), NSO + CNO(I) and NSO + OO(I) showed a reduction by 53.3, 42.6, 65.3 and 55.4 %, respectively, while the conjugated diene values showed a reduction by 75.0, 66.9, 76.7 and 75.3 %, respectively, as compared to NSO during the incubation period. This is probably the first report on the stability improvement of niger seed oil through blending and interesterification.     

Healthier lipid combination oil‐in‐water emulsions prepared with various protein systems: an approach for development of functional meat products

Five protein‐stabilized oil‐in‐water emulsions were prepared using sodium caseinate (O/SC), soy protein isolate (O/SPI), sodium caseinate and microbial transglutaminase (O/SC + MTG), sodium caseinate, microbial transglutaminase and meat slurry (O/SC + MTG + MS) and SPI, sodium caseinate and microbial transglutaminase (O/IPS + SC + MTG); their composition (proximate analysis and fatty acid profile) and physicochemical characteristics were examined. The lipid phase was a combination of healthy fatty acids from olive, linseed and fish oils, containing low proportions (15%) of saturated fatty acids (SFA) and high proportions of monounsaturated fatty acids (MUFA, 47%) and polyunsaturated fatty acids (PUFA, 36%), with a PUFA/SFA ratio >2, and a n‐6/n‐3 PUFA ratio of 0.4. All the oil‐in‐water emulsions showed high thermal and creamy stability. Results of penetration test and dynamic rheological properties showed la existencia de different types of oil‐in‐water emulsion structures according to stabilizing system of emulsion. Those structures ranged from concentrate solution‐like (stabilized only with SC) (gel strength 0.06 mJ) to gel‐like (samples containing MTG) behaviours (gel strength ranged between 3.4 and 6.2 mJ). Morphological differences in the organization of the network structure were observed (by scanning electron microscopy) as functions of the protein system used to stabilize the oil‐in‐water emulsions.     

Postprandial Lipid Responses do not Differ Following Consumption of Butter or Vegetable Oil when Consumed with Omega-3 Polyunsaturated Fatty Acids

Dietary saturated fat (SFA) intake has been associated with elevated blood lipid levels and increased risk for the development of chronic diseases. However, some animal studies have demonstrated that dietary SFA may not raise blood lipid levels when the diet is sufficient in omega‐3 polyunsaturated fatty acids (n‐3PUFA). Therefore, in a randomised cross‐over design, we investigated the postprandial effects of feeding meals rich in either SFA (butter) or vegetable oil rich in omega‐6 polyunsaturated fatty acids (n‐6PUFA), in conjunction with n‐3PUFA, on blood lipid profiles [total cholesterol, low density lipoprotein cholesterol (LDL‐C), high density lipoprotein cholesterol (HDL‐C) and triacylglycerol (TAG)] and n‐3PUFA incorporation into plasma lipids over a 6‐h period. The incremental area under the curve for plasma cholesterol, LDL‐C, HDL‐C, TAG and n‐3PUFA levels over 6 h was similar in the n‐6PUFA compared to SFA group. The postprandial lipemic response to saturated fat is comparable to that of n‐6PUFA when consumed with n‐3PUFA; however, sex‐differences in response to dietary fat type are worthy of further attention.     

Healthier lipid combination as functional ingredient influencing sensory and technological properties of low‐fat frankfurters

Oil (healthier lipid combination of olive, linseed and fish oils)‐in‐water emulsions stabilized with different protein systems (prepared with sodium caseinate (SC), soy protein isolate (SPI) and microbial transglutaminase (MTG)) were used as pork backfat replacers in low‐fat frankfurters. Composition (proximate analysis and fatty acid profile), sensory analysis and technological (processing and purge losses, texture and colour) properties of frankfurters were analysed as affected by the type of oil‐in‐water emulsion and by chilling storage (2°C, 41 days). Frankfurters produced with oil combinations had lower levels of saturated fatty acids (SFA, 19.3%), similar levels of MUFA (46.9%) and higher levels of PUFA (33.6%) than control frankfurters (all pork fat) (39.3, 49.5 and 10.6%, respectively). PUFA/SFA and n‐6/n‐3 PUFA ratios in control sample were 0.27 and 9.27; in reformulated frankfurters the PUFA/SFA ratio was higher (1.7) and the n‐6/n‐3 PUFA ratio was lower (0.47). In general, frankfurters had good fat and water binding properties. Colour parameters were affected by formulation and storage time. Compared to control sample, frankfurters made with oil‐in‐water emulsions had higher (p<0.05) hardness, springiness and chewiness values. Emulsified oil stabilizing systems did not affect sensory characteristics of frankfurters, and all products were judged as acceptable.     

Dietary fatty acids regulate cholesterol induction of liver CYP7α1 expression and bile acid production

In the present study we investigated the effects of dietary fats containing predominantly PUFA, monounsaturated FA (MUFA), or saturated FA (SFA) on lipid profile and liver cholesterol 7α-hydroxylase (CYP7α1) mRNA expression and bile acid production in C57BL/6J mice. The animals (n=75) were randomly divided into five groups and fed a basic chow diet (AIN-93G) (BC diet), a chow diet with 1g/100g of cholesterol (Chol diet), a chow diet with 1g/100g of cholesterol and 14g/100g of safflower oil (Chol+PUFA diet), a chow diet with 1g/100g of cholesterol and olive oil (Chol+MUFA diet), or a chow diet with 1g/100g of cholesterol and myristic acid (Chol+SFA diet) for 6 wk. The results showed that the Chol+SFA diet decreased CYP7α1 gene expression and bile acid pool size, resulting in increased blood and liver cholesterol levels. Addition of PUFA and MUFA to a 1% cholesterol diet increased the bile acid pool production or bile acid excretion and simultaneously decreased liver cholesterol accumulation despite decreased CYP7α1 mRNA expression. The results indicate that the decreased bile acid pool size induced by the SFA diet is related to inhibition of the liver CYP7α1 gene expression, but an increased bile acid pool size and improved cholesterol homeostasis are disassociated from the liver CYP7α1 gene expression.     

Effects of the ratio of polyunsaturated and monounsaturated fatty acid to saturated fatty acid on rat plasma and liver lipid concentrations

The effects of dietary monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid+MUFA/saturated fatty acid (PUFA+MUFA/SFA) ratio on plasma and liver lipid concentrations were studied. In experiment I, when rats were fed with 40% fat (energy%, PUFA/SFA ratio 1.0) and 1% (w/w) cholesterol (C) diets for 21 d, a large amount of MUFA (28.1 energy%, PUFA+MUFA/SFA=5.7) in the diet was found to increase the plasma total C, triacylglycerol (TAG), and phospholipid (PL) as compared with the low-MUFA diet (7.0 energy%, PUFA+MUFA/SFA=1.4). The plasma very low density lipoprotein (VLDL)-C, VLDL-TAG, VLDL-PL, and low density lipoprotein (LDL)-C increased significantly in the high-MUFA diet group, but high density lipoprotein (HDL)-C did not change significantly. The high-MUFA diet resulted in greater accumulation of liver C but lesser accumulation of TAG. In experiment II, when dietary SFA was fixed at a certain level (13.2 energy%; PUFA+MUFA/SFA=2.0), rats given a larger amount of MUFA (23.1 energy%; PUFA/MUFA=0.2; MUFA/SFA=1.8) showed higher plasma and liver C levels than did the low-MUFA diet (7.7 energy%; PUFA/MUFA=2.5; MUFA/SFA=0.6). When PUFA was fixed at a certain level (24.4 energy%), there was not a significant difference in the plasma C level between the high-and low-MUFA dietary groups (PUFA+MUFA/SFA=4.8 and 8.4), but the higher PUFA+MUFA/SFA diet, which was high in MUFA/SFA ratio, significantly decreased the plasma HDL-C and TAG levels. However, when MUFA content was fixed at a certain level (16.4 energy%), no significant difference was observed between the two groups with different PUFA/SFA ratios of 0.2 and 4.1, but liver C level was raised in the higher PUFA/SFA diet. It appears that the PUFA/SFA ratio alone is unsuitable to predict the change of plasma C level, because a large amount of dietary MUFA may lead to an increase of plasma and liver lipids in rats. It seems that the prerequisites for keeping low plasma and liver C are (i) low MUFA/SFA ratio, (ii) high PUFA/MUFA ratio, and (iii) PUFA+MUFA/SFA ratio not to exceed 2.     

Effects of Rice Bran Oil Enriched with n-3 PUFA on Liver and Serum Lipids in Rats

Lipase-catalyzed interesterification was used to prepare different structured lipids (SL) from rice bran oil (RBO) by replacing some of the fatty acids with α-linolenic acid (ALA) from linseed oil (LSO) and n-3 long chain polyunsaturated fatty acids (PUFA) from cod liver oil (CLO). In one SL, the ALA content was 20% whereas in another the long chain n-3 PUFA content was 10%. Most of the n-3 PUFA were incorporated into the sn-1 and sn-3 positions of triacylglycerol. The influence of SL with RBO rich in ALA and EPA + DHA was studied on various lipid parameters in experimental animals. Rats fed RBO showed a decrease in total serum cholesterol by 10% when compared to groundnut oil (GNO). Similarly structured lipids with CLO and LSO significantly decreased total serum cholesterol by 19 and 22% respectively compared to rice bran oil. The serum TAGs level of rats fed SLs and blended oils were also significantly decreased by 14 and 17% respectively compared to RBO. Feeding of an n-3 PUFA rich diet resulted in the accumulation of long chain n-3 PUFA in various tissues and a reduction in the long chain n-6 PUFA. These studies indicate that the incorporation of ALA and EPA + DHA into RBO can offer health benefits.     

The effect of dietary fatty acid balance on myocardial lesions in male rats

Three hundred (experiment I) and 350 (experiment II) weanling, 3-week-old male Sprague-Dawley rats weighing between 40–50 g were randomly assigned two per cage and 50 per dietary treatment to study the effect of dietary fatty acid balance on myocardial lesions. The following oils were tested: Experiment I.Brassica napus var. Tower rapeseed oil [Tower RSO, 1974 cultivar and 1975 cultivar, each containing 0.3% erucic (22∶1) acid];B. napus var. Zephyr RSO containing 0.9% 22∶1; corn oil; olive oil; and soybean oil. Experiment II.B. napus var. Tower RSO (1974 cultivar), olive oil, soybean oil, and the following oils to which was added the indicated level of free 22∶1; Tower +0.5% 22∶1; Tower +5.6% 22∶1; olive oil +4.4% 22∶1; soybean oil +5.7% 22∶1. In each case the oils were incorporated in a semisynthetic diet at a level of 20% by weight. Heart and heart lipid weights of rats fed the different oils did not differ statistically from each other. Fatty acid analyses of heart lipids revealed that the fatty acid composition of the cardiac lipids reflected that of the diet fed. In experiment I, there was a definite but significantly lower incidence (P<0.01) and severity (P<0.01) of heart lesions in rats fed control oils (corn, olive, soybean) than in rats fed rapeseed oils. Also, in experiment II, a definite but lower incidence and severity of heart lesions occurred in rats fed control oils (soybean, olive) compared to rats fed Tower RSO or this oil with added free 22∶1. Adding 22∶1 to an oil naturally high in 18∶3 (soybean) did not alter the incidence of heart lesions, whereas adding 22∶1 to an oil naturally high in 18∶1 (olive) increased significantly (P<0.01) both the incidence and severity of heart lesions. Thus, it appears that the background incidence of heart lesions that are found in the rat in any case, and which are increased by rapeseed oil feeding, is caused by the imbalanced fatty acid composition of the oil for the growing rat, i.e. high monoenes (18∶1, 20∶1, and 22∶1) and high 18∶3 and is not only due to the presence of excess 18∶3. Contribution No. 706, Animal Research Institute.     

Characterization and chemometric study of crude and refined oils from table olive by‐products

Table olive processing produces defective fruits and the conditioning operations give rise to solid by‐products which are processed to obtain oil. In this study, the most relevant characteristics of crude oils extracted from table olive by‐products were high average acidity values (4.5%, green olives; 8.1%, ripe olives), ECN42 values of 0.34 (green olives) and 0.10 (ripe olives), while 2‐mono‐palmitin averaged 0.92%. The overall content of sterols was 2257 mg/kg (green olives) and 1746 mg/kg (ripe olives), while the concentration of cholesterol was 36 mg/kg (green olives) and 19 mg/kg (ripe olives). The effect of refining was mainly reflected by a decrease in acidity and sterols. Although most characteristics were in agreement with the established regulation for olive oil, the overall trans fatty acid content, the low apparent β‐sitosterol content, and the relatively high cholesterol content prevented their inclusion into classes of crude or refined lampante or pomace olive oils, not even into the vegetable oil category. Therefore, the oils analyzed should be considered for non‐edible purposes. The physicochemical characteristics used for chemometric discrimination permitted discrimination among types of oils (crude, 100%; physically refined, 90%; chemically refined, 100%), elaboration styles (green and ripe olives, 100%) and cultivars (Gordal, Manzanilla, Hojiblanca and Cacereña, 100%), with the sterol composition being the most useful parameter for discrimination.     

Einfluß der Hydrierung auf Haltbarkeit und ernährungsphysiologische Eigenschaften von Qualitätsrapsölen

Effect of Hydrogenation on Stability and Nutritional Properties of Low-Erucic Rapeseed Oils Low-erucic rapeseed oils, Lesira and Erglu, were converted to more stable edible oils by selective hydrogenation of the linolenic acid moieties while retaining most of the linoleic acid groups. Feeding Lesira oil, hydrogenated Lesira oil, soybean oil and hydrogenated soybean oil to rats did not result in any appreciable differences in growth rates, whereas feeding conventional rapeseed oil caused extensive depression of growth. Among all the groups of animals the group fed conventional rapeseed oil showed the highest weights of heart and liver. The fatty acid patterns of depot and organ lipids did not show any major difference between the groups fed hydrogenated fats and those fed the corresponding unhydrogenated oils. The fatty acid composition of the organ lipids did not reveal deficiency in essential fatty acids. In the groups fed Lesira oil and hydrogenated Lesira oil half of the animals investigated exhibited myocardial lesions of light degree, probably due to the relatively high residual level of long-chain monoenoic fatty acids, whereas in the groups fed soybean oil and hydrogenated soybean oil only one-eighth of the rats examined exhibited such effects. The occurrence and severity of these myocardial lesions are known to be much higher in rats fed conventional rapeseed oils.     

Cholesterol‐lowering effect of plant sterols

Intake of plant sterols (4‐desmethyl sterols, phytosterols) reduces cholesterol absorption and lowers serum total and LDL cholesterol levels in humans. The use of dietary plant sterol regimens for lowering elevated serum cholesterol values has recently gained much interest, especially after the commercial introduction of margarines containing plant stanols esterified with fatty acids. The solubility of free, crystalline plant sterols and stanols in edible oils and fats is low, limiting their use especially in fat‐containing food. By esterifying of, e.g., plant stanols with fatty acids derived from a vegetable oil fatty acid ester of plant stanols with fat‐like properties are obtained. These fat‐soluble forms of plant stanols provide a technically feasible way of introducing the adequate daily amount of plant sterol into foods for optimal reduction of the cholesterol absorption, without changing the taste of the finished product. The cholesterol‐lowering effect of plant stanol esters has been extensively studied. Plant stanol esters effectively restrict the absorption of both dietary and biliary cholesterol causing plant stanol specific reductions in serum total and LDL cholesterol levels of up to 10% and 14%, respectively. Serum HDL cholesterol and triglyceride levels are not affected. The cholesterol‐lowering effect of plant stanol esters complements the beneficial effects of a healthy diet and cholesterol medication.     

Formation of 4‐Hydroxy‐2‐Trans‐Nonenal,a Toxic Aldehyde,in Thermally Treated Olive and Sunflower Oils

4‐Hydroxy‐2‐trans‐nonenal (HNE) is a toxic aldehyde produced mostly in oils containing polyunsaturated fatty acid due to heat‐induced lipid peroxidation. The present study examined the effects of the heating time, the degree of unsaturation, and the antioxidant potential on the formation of HNE in two light olive oils (LOO) and two sunflower oils (one high oleic and one regular) at frying temperature. HNE concentrations in these oil samples heated for 0, 1, 3, and 5 hours at 185 °C were measured using high‐performance liquid chromatography. The fatty‐acid distribution and the antioxidant capacity of these four oils were also analyzed. The results showed that all oils had very low HNE concentrations (<0.5 μg g^?1 oil) before heating. After 5 hours of heating at 185 °C, HNE concentrations were increased to 17.98, 25.00, 12.51, and 40.00 μg g^?1 in the two LOO, high‐oleic sunflower oil (HOSO), and regular sunflower oil (RSO), respectively. Extending the heating time increased HNE formation in all oils tested. It is related to their fatty‐acid distributions and antioxidant capacities. RSO, which contained high levels of linoleic acid (59.60%), a precursor for HNE, was more susceptible to degradation and HNE formation than HOSO and LOO, which contained only 6–8% linoleic acid.     

Detection of Furanoid Fatty Acids in Soya-Bean Oil – Cause for the Light-Induced Off-Flavour

The following furanoid fatty acids were detected in soya-bean oil (SBO), wheat germ oil, rapeseed oil and corn oil: 10,13-epoxy-11-methyloctadeca-10,12-dienoic acid(I),10,13-epoxy-11,12-dimethyloctadeca-10,12-dienoid acid (II), 12,15-epoxy-13,14-dimethyleicosa-12,14-dienoic acid (III). A model experiment indicated that II and III were quickly photooxidized with formation of the intense flavour compound 3-methyl-2-4-nonanedione (MND) as secondary product. MND causes the light-induced off-flavour of SBO. A method for the quantification of the three furanoid fatty acids in vegetable oils was developed. The amounts of II and III were relatively high (0.02-0.04%) in unprocessed and refined SBO and in one sample of wheat germ oil and quite low (0.0015–0.0035%) in corn oil and rapeseed oil. The furanoid fatty acids I, II and III were absent on olive and sunflower oils.     

Multivariate Data Analysis of Fatty Acid Content in the Classification of Olive Oils Developed Through Controlled Crossbreeding

The fatty acid (FA) composition of 540 Tunisian virgin olive oil hybrids (VOO) were classified by principal component analysis (PCA). Pearson correlation between FA variables revealed an inverse association between C18:1 and C18:2; C18:1 and C16:0, while C16:0 and C16:1 were positively correlated. PCA yielded five significant PCs, which together account for 79.95% of the total variance; with PC1 contributing 36.84% of the total. Eigenvalue analysis revealed that PC1 was mainly attributed to C18:1, monounsaturated fatty acids (MUFA) and the ratios oleic/linoleic (O/L) and monounsaturated fatty acids/polyunsaturated fatty acids (MUFA/PUFA); PC2, by C16:0, saturated fatty acids (SFA) and the palmitic/linoleic ratio (P/L); PC3 by C18:2 and C22:0, PC4 by C18:0 and PC5, by C17:1. Then, PCA analysis indicated that in addition to C16:0, C18:0, C18:1, C17:1, and C22:0, MUFA, SFA and the ratios O/L, P/L and MUFA/PUFA were determined to be the main factors responsible for the olive oil hybrids discrimination.     

Unusual effects of some vegetable oils on the survival time of stroke-prone spontaneously hypertensive rats

Preliminary experiments have shown that a diet containing 10% rapeseed oil (low-erucic acid) markedly shortens the survival time of stroke-prone spontaneously hypertensive (SHRSP) rats under 1% NaCl loading as compared with diets containing perilla oil or soybean oil. High-oleate safflower oil and high-oleate sunflower oil were found to have survival time-shortening activities comparable to that of rapeseed oil; olive oil had slightly less activity. A mixture was made of soybean oil, perilla oil, and triolein partially purified from high-oleate sunflower oil to adjust the fatty acid composition to that of rapeseed oil. The survival time of this triolein/mixed oil group was between those of the rapessed oil and soybean oil groups. When 1% NaCl was replaced with tap water, the survival time was prolonged by ∼80%. Under these conditions, the rapeseed oil and evening primrose oil shortened the survival time by ∼40% as compared with n-3 fatty acid-rich perilla and fish oil; lard, soybean oil, and safflower oil with relatively high n-6/n-3 ratios shortened the survival time by roughly 10%. The observed unusual survival time-shortening activities of some vegetable oils (rapeseed, high-oleate safflower, high-oleate sunflower, olive, and evening primrose oil) may not be due to their unique fatty acid compositions, but these results suggest that these vegetable oils contain factor(s) which are detrimental to SHRSP rats.     

Effects of dietary marine oils and olive oil on fatty acid composition, platelet membrane fluidity, platelet responses, and serum lipids in healthy humans

The influence of various dietary marine oils and olive oil on fatty acid composition of serum and platelets and effects on platelets and serum lipids were investigated as part of an extensive study of the effects of these oils on parameters associated with cardiovascular/thrombotic diseases. Healthy volunteers (266) consumed 15 mL/d of cod liver oil (CLO); whale blubber oil (refined or unrefined); mixtures of seal blubber oil and CLO; or olive oil/CLO for 12 wk. In the CLO, seal oil/CLO, and whale oil groups, serum levels of eicosapentaenoic acid (EPA) were increased. In platelets, EPA was increased in the CLO, seal/CLO, and olive oil/CLO groups. The localization of n-3 polyunsaturated fatty acids in the triacylglycerols did not seem to influence their absorption. Intake of oleic acid is poorly reflected in serum and platelets. No significant differences in triacylglycerols (IG), total cholesterol, or high density lipoprotein cholesterol were observed, even though TG were reduced in the CLO, CLO/seal oil, and whale oil groups. Mean platelet volume increased significantly in both whale oil groups and the CLO/olive oil group. Platelet count was significantly reduced in the refined whale oil group only. Lipopolysaccharide-stimulated blood tended to generate less thromboxane B₂ in CLO, CLO/seal, and CLO/olive groups. The whale oils tended to reduce in vivo release of β-thromboglobulin. In conclusion, intake of various marine oils causes changes in platelet membranes that are favorably antithrombotic. The combination of CLO and olive oil may produce better effects than these oils given separately. The changes in platelet function are directly associated with alterations of fatty acid composition in platelet membranes.     

Deterioration of diacylglycerol‐ and triacylglycerol‐rich oils during frying of potatoes

The stabilities of a commercial diacylglycerol‐rich oil (DAG) and a salad oil (TAG) that had been prepared from a mixture of rapeseed and soybean oils were compared while frying potatoes at 180 °C for 3 h. The representative chemical and physical characteristics of the oils were assessed before and after frying, together with the amount of volatile aldehydes in the exhaust of frying. Among the deterioration indications, the carbonyl value, polymer content, and residual polyunsaturated fatty acid content were similar and not significantly different between the TAG and DAG. On the other hand, the characteristics relating to free fatty acids, i.e. the acid value and emission of chemiluminescence at 100 °C, were greater and the smoke and flash points were lower in the DAG than in the TAG. An irritating odor was generated from the DAG after 1 h of frying and got stronger as frying continued. These results suggested that DAG more easily forms free fatty acids under frying conditions than TAG.