[Show abstract][Hide abstract] ABSTRACT: Appropriate activation of CD4(+) T cells is fundamental for efficient initiation and progression of acquired immune responses. Here, we showed that CD4(+) T-cell activation is dependent on changes in membrane n-3 polyunsaturated fatty acids (PUFAs) and is dynamically regulated by the type of signals provided by dendritic cells (DCs). Upon interaction with DCs primed by different concentrations and species of gut bacteria, CD4(+) T cells were activated according to the type of DC stimulus. The levels of CD80 were found to correlate to the levels of expression of CD28 and to the proliferation of CD4(+) T cells, while the presence of CD40 and CD86 on DCs inversely affected inducible costimulator (ICOS) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) levels in CD4(+) T cells. For all DC stimuli, cells high in n-3 PUFAs showed reduced ability to respond to CD28 stimulation, to proliferate, and to express ICOS and CTLA-4. Diminished T-cell receptor (TCR) and CD28 signalling was found to be responsible for n-3 PUFA effects. Thus, the dietary fatty acid composition influences the overall level of CD4(+) T-cell activation induced by DCs, while the priming effect of the DC stimuli modulates CD80, CD86 and CD40 levels, thereby affecting and shaping activation of acquired immunity by differential regulation of proliferation and costimulatory molecule expression in CD4(+) T cells.
[Show abstract][Hide abstract] ABSTRACT: Isomers of conjugated linoleic acids (CLA) reduce fat mass (FM) and increase insulin sensitivity in some, but not all, murine studies. In humans, this effect is still debatable. In this study, we compared the effect of 2 CLA supplements on total and regional FM assessed by dual energy X-ray absorptiometry, changes in serum insulin and glucose concentrations, and adipose tissue (AT) gene expression in humans. In a double-blind, parallel, 16-wk intervention, we randomized 81 healthy postmenopausal women to 1) 5.5 g/d of 40/40% of cis9,trans11-CLA (c9,t11-CLA) and trans10,cis12-CLA (t10,c12-CLA) (CLA-mix); 2) cis9, trans11-CLA (c9,t11-CLA); or 3) control (olive oil). We assessed all variables before and after the intervention. The CLA-mix group had less total FM (4%) and lower-body FM (7%) than the control (P = 0.02 and < 0.001, respectively). Post hoc analyses showed that serum insulin concentrations were greater in the CLA-mix group (34%) than the control group (P = 0.02) in the highest waist circumference tertile only. AT mRNA expression of glucose transporter 4, leptin, and lipoprotein lipase was lower, whereas expression of tumor necrosis factor-alpha was higher in the CLA-mix group than in the control group (P < 0.04). In conclusion, a 50:50 mixture of c9,t11- and t10,c12-CLA isomers resulted in less total and lower-body FM in postmenopausal women and greater serum insulin concentrations in the highest waist circumference tertile. Future research is needed to confirm the insulin desensitizing effect of the CLA mixture and the effect on the mRNA expression of adipocyte-specific genes in humans.
Full-text · Article · Jul 2009 · Journal of Nutrition
[Show abstract][Hide abstract] ABSTRACT: A mixture of trans-10, cis-12 (t10,c12) and cis-9, trans-11 (c9,t11) conjugated linoleic acid (CLA mixture) reduced atherosclerosis in animals, thus the effect of these isomers on endothelial dysfunctions leading to inflammation and atherosclerosis is of interest. We gave 75 healthy postmenopausal women a daily supplement of 5.5 g of oil rich in either CLA mixture, an oil rich in the naturally occurring c9,t11 CLA (CLA milk), respectively, or olive oil for 16 wk in a double-blind, randomized, parallel intervention study. We sampled blood and urine before and after the intervention. The ratios of total cholesterol:HDL cholesterol and concentrations of C-reactive protein, fibrinogen, and plasminogen activator inhibitor-1 were significantly higher in women supplemented with the CLA mixture than in those supplemented with CLA milk. Plasma triacylglycerol was significantly higher and HDL cholesterol was lower in women supplemented with the CLA mixture than with olive oil. Both CLA supplements increased lipid peroxidation, a marker of in vivo oxidative stress measured as urinary free 8-iso-prostaglandin F(2alpha). However, the CLA mixture increased lipid peroxidation more than the CLA milk did. The plasma cytokines interleukin-6 and tumor necrosis factor-alpha were not affected by the treatments, nor were any of the other variables measured. In conclusion, oil containing trans-10,cis-12 CLA has several adverse effects on classical and novel markers of coronary vascular disease, whereas the c9,t11 CLA isomer is more neutral, except for a small but significant increase in lipid peroxidation compared with olive oil.
No preview · Article · Aug 2008 · Journal of Nutrition
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to determine the incorporation of conjugated linoleic acid (CLA) into triacylglycerols (TAG) and phospholipids (PL) of tissues and plasma, and to interpret the role of dietary-derived vaccenic acid (VA) in increasing the tissue content of CLA (c9,t11) and the influence on the fatty acid profile. We fed five groups of rats semi-purified diets with varying levels of CLA and VA: control butter with low CLA (c9,t11) and VA; control butter added 5% CLA (c9,t11); control butter added 5% Tonalin [equal amount of CLA (c9,t11) and CLA (t10,c12)]; control butter added 5% VA; butter with high CLA (c9,t11) and VA (H-CLA), for 3 weeks. The highest incorporation of CLA (c9,t11) was found in adipose tissue, and the lowest was observed in liver. Low intake of CLA (c9,t11) combined with high intake of VA resulted in a higher incorporation of CLA (c9,t11) in tissues due to the conversion of VA to CLA (c9,t11), compared to feeding CLA (c9,t11) without VA. However, in enterocytes, the proportion of CLA (c9,t11) was low after feeding VA, indicating no or only a minor conversion of VA to CLA (c9,t11) in the intestine. The incorporation of CLA (t10,c12) into TAG from plasma and tissues was generally much lower than that of the CLA (c9,t11) isomer, except in the enterocyte TAG, which had similar proportions of the two isomers.
No preview · Article · Dec 2006 · European Journal of Lipid Science and Technology
[Show abstract][Hide abstract] ABSTRACT: Long-chain polyunsaturated fatty acids (LCPUFA) in breastmilk, specifically docosahexaenoic acid (DHA), are important for infant brain development. Accretion of DHA in the infant brain is dependent on DHA-status, intake and metabolism. The aim of this study was to describe changes in maternal and infant erythrocyte (RBC) DHA-status during the first four months of lactation. We examined 17 mothers and their term infants at 1, 2 and 4 months of age. Milk samples and RBC from the mothers and infants were obtained and analysed for fatty acid composition. Comparative analysis of the results showed that the content of DHA in maternal RBC-phosphatidylcholine (PE) decreased over the four month period and this was not accompanied by a decrease in DHA in infant RBC-PE (P = 0.005). The ratio of n-6 PUFA to n-3 PUFA increased over time in maternal RBC-PE, but not in infant RBC-PE (P < 0.001). The level of 22:5n-6 and the ratio of LCPUFA to precursor PUFAs in infant RBC was higher than in maternal RBC phospholipids. (P = and P < 0.001 respectively). We found a decrease in the level of LCPUFA in milk, specifically AA. However, we did not observe a significant decrease in milk DHA, which may have been due to two outliers. These results indicate better DHA-status and a higher n-3/n-6 PUFA in RBC of infants than in mothers. Whether these differences reflect preferential n-3 PUFA transfer via breastmilk or differences in PUFA-metabolism and utilization remains to be shown.
No preview · Article · Jan 2006 · Maternal and Child Nutrition
[Show abstract][Hide abstract] ABSTRACT: The aim of the present study was to investigate the effect of trans-18:1 isomers compared to other fatty acids, especially saturates, on the postprandial fatty acid composition of triacylglycerols (TAG) in chylomicrons and VLDL.
A randomised crossover experiment where five interesterified test fats with equal amounts of palmitic acid (P fat), stearic acid (S fat), trans-18:1 isomers (T fat), oleic acid (O fat), or linoleic acid (L fat) were tested.
A total of 16 healthy, normolipidaemic males (age 23+/-2 y) were recruited.
The participants ingested fat-rich test meals (1 g fat per kg body weight) and the fatty acid profiles of chylomicron and VLDL TAG were followed for 8 h.
The postprandial fatty acid composition of chylomicron TAG resembled that of the ingested fats. The fatty acids in chylomicron TAG were randomly distributed among the three positions in accordance with the distributions in test fats. Calculations of postprandial TAG concentrations from fatty acid data revealed increasing amounts up to 4 h but lower response curves (IAUC) for the two saturated fats in accordance with previous published data. The T fat gave results comparable to the O and L fats. The test fatty acids were much less reflected in VLDL TAG and there was no dietary influence on the response curves.
The fatty acid composition in the test fats as well as the positional distributions of these were maintained in the chylomicrons. No specific clearing of chylomicron TAG was observed in relation to time.
Preview · Article · Feb 2005 · European Journal of Clinical Nutrition
[Show abstract][Hide abstract] ABSTRACT: Dietary medium-chain fatty acids (MCFAs) are of nutritional interest because they are more easily absorbed from dietary medium-chain triacylglycerols (MCTs) than are long-chain fatty acids from, for example, vegetable oils. It has generally been claimed that MCFAs do not increase plasma cholesterol, although this claim is poorly documented.
We compared the effects of a diet rich in either MCFAs or oleic acid on fasting blood lipids, lipoproteins, glucose, insulin, and lipid transfer protein activities in healthy men.
In a study with a double-blind, randomized, crossover design, 17 healthy young men replaced part of their habitual dietary fat intake with 70 g MCTs (66% 8:0 and 34% 10:0) or high-oleic sunflower oil (89.4% 18:1). Each intervention period lasted 21 d, and the 2 periods were separated by a washout period of 2 wk. Blood samples were taken before and after the intervention periods.
Compared with the intake of high-oleic sunflower oil, MCT intake resulted in 11% higher plasma total cholesterol (P = 0.0005), 12% higher LDL cholesterol (P = 0.0001), 32% higher VLDL cholesterol (P = 0.080), a 12% higher ratio of LDL to HDL cholesterol (P = 0.002), 22% higher plasma total triacylglycerol (P = 0.0361), and higher plasma glucose (P = 0.033). Plasma HDL-cholesterol and insulin concentrations and activities of cholesterol ester transfer protein and phospholipid transfer protein did not differ significantly between the diets.
Compared with fat high in oleic acid, MCT fat unfavorably affected lipid profiles in healthy young men by increasing plasma LDL cholesterol and triacylglycerol. No changes in the activities of phospholipid transfer protein and cholesterol ester transfer protein were evident.
Full-text · Article · May 2004 · American Journal of Clinical Nutrition
[Show abstract][Hide abstract] ABSTRACT: The purpose of this work was to study the impact of storage conditions, such as light and temperature, on the development of volatile compounds in processed cheese. Cheese in glass containers was stored at 5, 20 or 37°C in light or darkness for up to 1 yr. Dynamic headspace and gas chromatography/mass spectrometry was used for quantifying 28 volatile organic compounds at eight stages during the storage period. Through principal component analysis, three important storage parameters could be identified. Principal components 1, 2 and 3 reflected storage time, conditions of light/darkness and storage temperature, respectively, and described 81, 8 and 4% of the total variance. All compound developments were shown to correlate positively with storage time. Storage in light resulted in a sharp rise not only in the concentration of especially octane, but also hexanal, heptanal, octanal and nonanal, compared to storage in the darkness. Rising temperature especially increased the concentrations of 2-propyl-1-pentanol, 2-hexanone, 2-octanone, 2-decanone, 2-tridecanone, octanal, nonanal and decanal.
No preview · Article · Mar 2002 · Lebensmittel-Wissenschaft und-Technologie
[Show abstract][Hide abstract] ABSTRACT: Sliced Havarti cheese in retail packages with modified atmosphere were stored at 5°C for up to 21 days exposed to light or protected against light. The changes in the volatile profile of the cheese was determined by dynamic headspace GC/MS. Fifty-seven compounds (aldehydes, alcohols, ketones, esters, lactones, and hydrocarbons) were identified and their relative abundance was followed during storage. The complete data set of volatiles of all Havarti cheeses was subjected to partial least squares regression (PLSR) analyses. During storage an increase in the content of some of the volatiles was observed. For Havarti cheeses exposed to light increasing levels of octane, 1-pentanol, nonanal, and tridecane were observed.
[Show abstract][Hide abstract] ABSTRACT: The effect of storage time and storage temperature on the formation of volatile compounds in dairy spreads was investigated. Dairy spreads were stored for 10 weeks at -18, 5 and 20 C, respectively, and analyzed after 0, 38, 54 and 67 days of storage. By means of a dynamic headspace GC/MS method using Tenax traps the dairy spreads were analyzed for volatile aromatic compounds. 61 components were identified and their relative content was followed during the storage period. Among these were four alcohols, 17 aldehydes, four esters, ten alkanes, 11 ketones and six lactones. A general increase in the concentration of most of the volatile compounds during storage was found. The content of volatile compounds in dairy spreads stored at -18 C was nearly constant or showed a rather low increase in the content during the storage period. Storage at higher temperatures (5 and 20 C) resulted in an increase in the content of most of the volatiles after 40 days of storage. The profiles obtained were subjected to multivariate data analysis to determine the volatiles potentially responsible for oxidized off-flavors in dairy spread. The volatiles were divided into three groups: one correlated with storage temperature and 5 C, one with storage time and 20 C and the last with storage time alone. Most of the volatiles were found in the highest concentration after storage at 20 C, but the content of some volatiles was highest after storage at 5 C.
No preview · Article · May 2001 · European Food Research and Technology
[Show abstract][Hide abstract] ABSTRACT: The antioxidative effects of gallic acid, EDTA, and extra emulsifier Panodan DATEM TR in mayonnaise enriched with 16% fish oil were investigated. EDTA reduced the formation of free radicals, lipid hydroperoxides, volatiles, and fishy and rancid off-flavors. The antioxidative effect of EDTA was attributed to its ability to chelate free metal ions and iron from egg yolk located at the oil-water interface. Gallic acid reduced the levels of both free radicals and lipid hydroperoxides but promoted slightly the oxidative flavor deterioration in mayonnaise and influenced the profile of volatiles. Gallic acid may therefore promote the decomposition of lipid hydroperoxides to volatile oxidation products. Addition of extra emulsifier reduced the lipid hydroperoxide levels but did not influence the level of free radicals or the oxidative flavor deterioration in mayonnaisse; however, it appeared to alter the profile of volatiles. The effect of the emulsifier on the physical structure and rheological properties depended on the presence of antioxidants.
No preview · Article · Mar 2001 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: The nutritional effect of the regiospecific distribution of fatty acids in edible fats is currently discussed due to an increased use of interesterification of fats for human consumption. However, disagreeing results have been reported which may be due to the varying composition of the dietary fats compared. Data on the fate of such lipids beyond the bloodstream is rather scarce and animal model studies are needed.
To compare the metabolism of butter oil and mixtures of butter and rapeseed oil, native or randomized, in a rat model. The regiospecific fatty acid distribution present in dietary fats was followed through absorption, chylomicron formation, and deposition in adipose tissue and in different liver lipids (triacylglycerols, phosholipids, and cholesterol esters).
Rats were fed for 6 weeks from weaning either butter oil (BO), a butteroil-rapeseed oil mixture 65:35 w/w (BR) or a randomized mixture of BR (tBR). Half of the animals were used for organ analysis, the rest for a postprandial study with the same fats and isolation of chylomicrons. The regiospecific distribution of the fatty acids present in the dietary fats was followed during metabolism by analyses of chylomicrons, depot fat and liver lipids, using regiospecific cleavage followed by TLC separation and quantification by GC.
Randomization of edible fat mixtures leading to equal distribution of fatty acids between TG positions is directly reflected in the composition of chylomicrons. During clearing by lipoprotein lipase this positional distribution is abolished and the regiospecific composition of triacylglycerols in adipose tissue is completely identical for BR and tBR. Chylomicron remnants, which are taken up by the liver, are correspondingly fully degraded to free fatty acids by hepatic lipase, and distribution of fatty acids in liver triacylglycerols, phospholipids and cholesterol esters are identical for the groups fed either BR or tBR. The group fed BO with a low content of linoleic acid is on the borderline of essential fatty acid-deficiency.
Randomization (interesterification) of butter oil with rapeseed oil (65:35 w/w) for use as edible fat did not have any impact on the fatty acid composition beyond the chylomicron step when compared to the native mixture.
No preview · Article · Feb 2001 · European Journal of Nutrition
[Show abstract][Hide abstract] ABSTRACT: The effect of the water-dispersible tocopherol preparation, Grindox 1032, and the oil-soluble tocopherol preparation, Toco 70, on oxidative stability in fish oil-enriched mayonnaise was examined. The two commercial antioxidant preparations were supplemented in different levels corresponding to 20-280 ppm tocopherol in addition to the 600 ppm present in the oils used for the mayonnaise. The oxidative stability was assessed by sensory analysis, the tendency of formation of free radicals, and concentrations of lipid hydroperoxides and volatile oxidation products. The effect of tocopherol on oxidation depended on the nature and the concentration of the tocopherol preparation employed, and it also depended on the parameters evaluated. Addition of high levels of Grindox 1032 (~140-280 ppm tocopherol) thus decreased the intensity of rancid off-flavor, but increased the formation of fishy off-flavors, the tendency of free radical formation and the concentration of certain volatiles. In contrast, low levels of Grindox 1032 (<70 ppm tocopherol) reduced the concentration of some volatiles, but did not seem to influence the off-flavor profile of the mayonnaise. Toco 70, which was only supplemented in low levels (<40 ppm tocopherol) increased the tendency for free radical formation, changed the profile of volatiles, and did not have a clear effect on the fishy and rancid off-flavor formation. Thus, additional tocopherol did not appear to be an efficient antioxidant in fish oil-enriched mayonnaise, perhaps because it cannot prevent the metal-catalyzed decomposition of peroxides, which we previously suggested to play an important role in mayonnaise.
No preview · Article · Jan 2001 · European Food Research and Technology
[Show abstract][Hide abstract] ABSTRACT: A fast (12 min) high-performance size exclusion chromatography (HPSEC) method for the separation of neutral lipid class hydroperoxides in the oil phases from fish oil enriched mayonnaises was developed. Detection and quantification were performed using the postcolumn fluorometric (FL) diphenyl-1-pyrenylphosphine oxidation principle. The reproducibilities judged by intra- and inter-assay variations were 0.64 and 7.2%, respectively. The HPSEC-FL method was applied to assess the effect of supplementations with emulsifier, gallic acid, and EDTA on the oxidative processes in the mayonnaises during storage. Substantial amounts of hydroperoxy triacylglycerols (TAGOOH) and cholesterol esters (CEOOH), together with traces of TAGOOH-dimers, were detected. All supplementations significantly decreased the levels of TAGOOH and to a lesser degree CEOOH. Supplementations with EDTA and gallic acid resulted in constant and slightly increasing levels of TAGOOH, respectively, thus affecting the oxidation mechanisms seen in reference mayonnaise. The emulsifier Panodan TR DATEM reduced the levels of TAGOOH as compared to the appropriate controls.
No preview · Article · Jan 2001 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: Protection against lipid oxidation and formation of unpleasant fishy and rancid off-flavors in oil-in-water food emulsions, such as fish oil enriched mayonnaise, is difficult to achieve. Volatile profiles from stored mayonnaises with different oil phase compositions were collected using a developed dynamic headspace sampling technique, in which interfering acetic acid was removed in situ with potassium hydroxide, and subsequently 148 volatiles were characterized and monitored by gas chromatography/mass spectrometry. Multivariate statistics showed correlation between the concentration of 62 volatiles and the fish oil and storage parameters, indicating the formation of lipid oxidation products, which impose fishy off-flavors. Further verification was obtained by gas chromatography/olfactometry, by which, among 78 odors, cis-4-heptenal and trans,cis-2,4-heptadienal were detected as distinct fishy notes. In total, 27 volatiles, including 1-penten-3-one, cis-2-penten-1-ol, cis-3-hexenal, cis-4-heptenal, 1-octen-3-one, 1,cis-5-octadien-3-one, 1-octen-3-ol, trans,cis-2, 4-heptadienal, and trans,cis-2,6-nonadienal, were suggested to contribute to the developed unpleasant fishy and rancid off-flavors.
No preview · Article · Nov 2000 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: To investigate the influence of physical structure on oxidative stability, mayonnaises enriched with 16% fish oil with three different droplet distributions were prepared. During storage at 20 degrees C the concentration of free radicals (measured by electron spin resonance), the intensity of the fishy and rancid off-flavours (judged by sensory analysis) and the concentrations of several volatile oxidation compounds (measured by GC-MS) were lower in mayonnaise with large oil droplets in the initial stage of the storage period. As small droplets imply a large oil/water (o/w) interfacial area, the data support the theory that lipid oxidation in mayonnaise is initiated at the o/w interface. After 3-4 weeks' storage, the oxidative progress was almost equal in different mayonnaises. Oxidative propagation thus appears less dependent of interfacial area. The droplet size also influenced rheological properties, e.g. mayonnaises with small droplets had higher gel strength and a more rigid structure. Although small droplets enhance rheological properties and stabilise emulsions physically, the oxidative deterioration apparently starts earlier as the interfacial area increases. This ought to be considered in processing strategies for emulsified food products,notably those containing highly unsaturated lipids.
No preview · Article · Jun 2000 · European Food Research and Technology
[Show abstract][Hide abstract] ABSTRACT: Oxidative protection of mayonnaises with 16% fish oil was studied during cold storage (5 7C) after supplementation with different tocopherol systems: the ternary antioxidant system ascorbic acid, lecithin and tocopherol (A/L/T), and two commercial mixtures, an oil-soluble (Toco 70) preparation and a water-soluble (Grindox 1032) preparation. The physical structure of the fish-oil-enriched mayonnaise was manipulated by adding extra emulsifier (Panodan TR) with the purpose of investigating whether or not this affected the antiox-idative activity of the tocopherol mixtures. A number of different analytical techniques HPLC (high-perform-ance liquid chromatography, gas chromatography mass spectrometry (GC-MS), sensory analysis, confocal laser scanning microscopy and rheological measure-ments) were employed to elucidate the chemical, senso-ry, structural and rheological aspects of the oxidation process. Discriminant partial least squares regression was used to analyse the data obtained. The three toco-pherol preparations not only affected the oxidative sta-bility of the mayonnaises differently, they also in-fluenced the rheological and structural properties of the mayonnaises in different ways. The rheological and structural properties of the mayonnaise were also af-fected by the addition of extra emulsifier, but this did not influence the formation of fishy and rancid off-fla-vours. Addition of the A/L/T system caused the imme-diate formation of distinct fishy and rancid off-flavours in the fresh mayonnaises. The volatile compounds trans-2-heptenal, 4-octen-3-one, 1-octen-3-ol, trans,cis-2,4-heptadienal, trans,trans-2,4-heptadienal, trans-2-oc-tenal, nonanal and trans,cis-2,6-nonadienal were thought to contribute to the fishy and rancid flavours. Addition of Toco 70 did not affect the sensory percep-tion of mayonnaise nor the development of volatile off-flavour compounds as evaluated by GC-MS, but the peroxide values were slightly increased in mayonnaise containing Toco 70 as compared to the other mayon-naises. Mayonnaise with Grindox 1032 seemed to have fewer fishy and rancid off-flavours than mayonnaises without antioxidant. This flavour-protective effect of Grindox 1032 was correlated to an increase in the size of the droplet diameter of mayonnaises supplemented with Grindox 1032.
Full-text · Article · Jan 2000 · European Food Research and Technology
[Show abstract][Hide abstract] ABSTRACT: A number of different analytical techniques (HPLC, GC-MS, sensory analysis, laser diffraction droplet size determination, confocal laser scanning mi-croscopy and rheological measurements) were em-ployed to elucidate both chemical, sensory, structural and rheological aspects of the oxidation process in mayonnaise containing 16% fish oil. The primary focus of the study was on the antioxidative effect of two dif-ferent types of commercial propyl gallate mixtures: an oil-soluble and a water-soluble preparation. The effect of adding extra emulsifier (Panodan TR), used to ma-nipulate the physical structure of the fish-oil-enriched mayonnaise and in turn affect the antioxidative activity of the propyl gallate mixtures, was also investigated. Mayonnaise with fish oil did not oxidise faster than mayonnaise without fish oil when judged from the chemical parameters tested. However, the fish-oil-en-riched mayonnaises developed unpleasant off-odours and off-flavours much faster than the mayonnaise with-out fish oil. Addition of the two different propyl gallate mixtures not only influenced negatively the sensory qualities but also affected the structure and the rheo-logical properties of the mayonnaise. Propyl gallate thus, in particular, promoted the development of fishy and rancid off-flavours during the storage of mayon-naise with fish oil, and this effect was especially pro-nounced for the water-soluble propyl gallate mixture. Four volatile oxidation compounds, namely 3-furalde-hyde, 2,4-heptadienal, 2,4-decadienal and ethyl ben-zene, appeared to correlate to the fishy and rancid off-flavours that developed in mayonnaises with propyl gallate. Addition of propyl gallate also resulted in in-creased peroxide values, and a less viscous mayonnaise with bigger droplets. The data thus demonstrated that the propyl gallate mixtures employed did not protect mayonnaise with fish oil against flavour deterioration due to oxidation during storage. In addition, the data showed that several structural and rheological paramet-ers were affected by the addition of propyl gallate.
Full-text · Article · Nov 1999 · European Food Research and Technology
[Show abstract][Hide abstract] ABSTRACT: The aim of this present project was to evaluate a more satisfactory effect on plasma lipoprotein profile of spreads based on dairy fat.
This study was designed as a randomised cross-over experiment with a three-week treatment separated by a three-week wash-out period. Sixty five grams of the fat content of the habitual diets was replaced by either butter/grapeseed oil (90:10) (BG); butter oil and low erucic rapeseed oil (65:35) (BR) or butter blended in a 1:1 ratio with a interesterified mixture of rapeseed oil and fully hydrogenated rapeseed oil (70: 30) (BS).
Thirteen healthy free-living young men (age 21-26 y) fulfilled the study.
At the beginning and end of each diet period two venous blood samples were collected. Triacylglycerol and cholesterol concentrations in total plasma and VLDL, LDL, IDL and HDL fractions were measured, as were apo A-1 and apo B concentrations. Fatty acid composition of plasma phospholipids, plasma cholesterol ester and platelets was also determined.
Significantly (P < 0.05) lower total and LDL-cholesterol concentrations were observed after the BR and BS period, compared to BG. The effect of BR and BS did not differ. BG and BR resulted in equal concentrations of HDL-C, but significantly higher than BS. Consequently, a significantly lower LDL-C/HDL-C ratio was seen after the BR treatment compared to BG and BS. Apo A-1 concentrations were not significantly different, but Apo B was significantly increased after BG.
Partially replacing milk fat with rapeseed oil seems to yield a more healthy spread. Stearic acid had a HDL-C lowering effect compared to milk fat, but did not affect LDL-C significantly. The addition of stearic acid did not improve the plasma lipoprotein profile for young men with low cholesterol levels.
Preview · Article · Aug 1999 · European Journal of Clinical Nutrition