Effects of ionizing radiation on some vegetable fats

The volatile compounds produced by irradiation, under vacuum at 6 megarads, in five vegetable fats were analyzed qualitatively and quantitatively by gas chromatography and mass spectrometry. A series of compounds,n-alkanes, 1-alkenes, internally unsaturated alkenes, alkadienes, alkatrienes, alkanals and methyl and ethyl esters of fatty acids, were identified in each of the fats studied. A wide variation occurs in the amounts of the volatiles produced from each fat. The major radiolytic products were few in number and were found to depend largely on the fatty acid composition of the fat. These compounds were essentially the hydrocarbons containing one or two carbon atoms less than the component fatty acids. This relationship was found consistent if radiolytic products of fats with different fatty acid compositions are compared or if the fatty acid composition of the same fat is altered by hydrogenation. The results correlate well with those of earlier studies on simple triglycerides.     

Alteration of Endogenous Fatty Acids Profile and Lipid Metabolism in Rats Caused by a High-Colleseed Oil and a High-Sunflower Oil Diet

Dietary fat has an important influence on mammalian lipid homeostasis. However, the relationship between dietary fat types and endogenous fatty acids (FAs) in organs as well as lipid homeostasis remains unclear enough. In this study, rats are randomly divided into a control group (CN), a high-colleseed oil group (COG), and a high-sunflower oil group (SOG). FAs profile in liver and visceral fats of rats in two high-fat (HF) diet groups is compared with that in CN. Oleic, γ-linolenic, eicosadienoic, and arachidonic acid accumulate in COG liver or visceral fats, but the levels of linoleic, eicosadienoic, docosanoic, and dihomo-γ-linolenic acid decrease in COG visceral fats. However, these FAs levels increased in SOG liver or visceral fats except dihomo-γ-linolenic and arachidonic acid which changed insignificantly. The trend of initial upregulation and then downregulation of lipid metabolism-related genes expression is noted in COG liver, including stearoyl-CoA desaturase. Upregulation of adiponectin (ADPN) expression in visceral fats and downregulation of ADPN receptor 2 (Adipo-R2) expression in livers of both HF groups are observed. Correlation analysis revealed positive correlations between specific FAs content and ADPN expression level. Negative correlations are observed between Adipo-R2 expression and the content of oleic, linoleic, and γ-linolenic acid in the SOG liver. Practical applications: Dietary fat not only provides energy but is also associated with lipid homeostasis. In this work, the authors investigate the distribution of fatty acids (FAs) in vivo and their influence on genes related to lipid metabolism induced by diets enriched in oleic acid or linoleic acid. The study suggests that dietary fats modulate lipid homeostasis not only by regulating endogenous FAs levels but also by affecting the expression of genes related to lipid metabolism. This study may support the research in lipid nutrition and rational intake of dietary fat.     

Muffins made with monoglyceride oleogels: Impact of fat replacement on sensory properties and fatty acid profile

Most shortenings used in baked products are solid fats high in saturated fatty acids that may also contain trans fatty acids, which are nutritionally unhealthy. Successful solid fat replacement requires maintaining not only the physicochemical properties, but also the sensory quality of the products. In this study, the sensory properties and lipid profile of muffins formulated with a previously optimized monoglyceride oleogel were compared with those of muffins made with a commercial margarine (Control). Untrained consumers (n = 130) evaluated the effect of the fat replacement on several sensory attributes using a 5-point hedonic scale. In comparison with the Control, the oleogel-based muffin (M_o) scored similarly for flavor and sponginess, but rated significantly higher for appearance and color. Based on overall quality score, consumers liked M_o more than the Control. The reformulated muffins had a significantly improved lipid profile, with a 68% reduction in saturated fats and an almost 4-fold increase in monounsaturated fats. This study supports the use of monoglyceride oleogels as full-fat substitutes to develop healthier bakery products, maintaining or improving consumer acceptance. It is expected that the promising results presented here will help the food industry to accelerate the transition from conventional solid fats to oleogels.     

Content and distribution oftrans-18:1 acids in ruminant milk and meat fats. Their importance in european diets and their effect on human milk

Thetrans-18:1 acid content and distribution in fats from ewe and goat milk, beef meat and tallow were determined by a combination of capillary gas-liquid chromatography and argentation thin-layer chromatography of fatty acid isopropyl esters. Thetrans isomers account for 4.5 ± 1.1% of total fatty acids in ewe milk fat (seven samples) and 2.7±0.9% in goat milk fat (eight samples). In both species, as in cow, the main isomer is vaccenic (trans-11 18:1) acid. The distribution profile oftrans-18:1 acids is similar among the three species. The contribution of ewe and goat milk fat to the daily intake oftrans-18:1 acids was estimated for people from southern countries of the European Economic Community (EEC): France, Italy, Greece, Spain, and Portugal. It is practically negligible for most of these countries, but in Greece, ewe and goat milk fat contributeca. 45% of the daily consumption oftrans-18:1 acids from all dairy products (0.63 g/person/day for a total of 1.34 g/person/day). Thetrans-18:1 acid contents of beef meat fat (ten retail cuts, lean part) and tallow (two samples) are 2.0 ± 0.9% and 4.6%, respectively, of total fatty acids (animals slaughtered in winter). Here too, the main isomer is vaccenic acid. Othertrans isomers have a distribution pattern similar to that of milk fat. Beef meat fat contributes less than one-tenth of milk fat to thetrans-18:1 acid consumed. The daily per capita intake oftrans-18:1 acids from ruminant fats is 1.3–1.8 g for people from most countries of the EEC, Spain and Portugal being exceptions (ca. 0.8 g/person/day). In France, the respective contributions of ruminant fats and margarines to the daily consumption oftrans-18:1 acids are 1.7 and 1.1 g/person/day (60 and 40% of total, respectively). These proportions, based on consumption data, were confirmed by the analysis of fat from milk of French women (ten subjects). The mean content oftrans-18:1 acids in human milk is 2.0 ± 0.6%, with vaccenic acid being the major isomer. Based on the relative levels of thetrans-16 18:1 isomer, we could confirm that milk fat is responsible for the major part of the daily intake oftrans-18:1 acids by French people. The daily individual intake oftrans-18:1 isomers from both ruminant fats and margarines for the twelve EEC countries varies from 1.5 g in Spain to 5.8 g in Denmark, showing a well-marked gradient from the southwest to the northeast of the EEC.     

Effect of PUFA at sn‐2 position in dietary triacylglycerols on the fatty acid composition of adipose tissues in non‐ruminant farm animals

The influence of the distribution of polyunsaturated fatty acids on the glycerol backbone of dietary triacylglycerols on the fatty acid profile of adipose tissue and muscle phospholipids was investigated in growing‐finishing pigs (48) and broiler chicken (84). The animals were fattened on barley/soybean meal diets supplemented with a blend of soybean oil and beef tallow, either in the ratio 3:1 w/w (high‐PUFA) or 1:3 w/w (low‐ PUFA). Part of the high‐ and low‐PUFA blends was chemically interesterified to randomly distribute all fatty acids over the three positions of the glycerol. Thus, two sets of diets of identical overall fatty acid composition, but differing in the distribution of fatty acids in the triacylglycerols, were fed. Growth performance and carcass composition were neither affected by fatty acid composition nor by randomisation of dietary fats in either animal species. Apparent digestibility of energy was slightly lower in pigs fed the low‐PUFA blends. Fatty acid profile of subcutaneous fat of pigs and broilers as well as of internal body fat (lamina subserosa) and muscle phospholipids of pigs varied according to the dietary fatty acid composition but was not affected by randomisation of dietary fats. These findings are explained in terms of the hydrolysis of TAG during transport of lipids from enterocytes to adipose tissue cells and the continuous lipolysis and re‐esterification of fatty acids that take place in adipose tissue cells.     

Composition of liver fats of mature and embryo sharks (galeocerdo tigrinus)

1. Two liver fats, one from the “mother” and the other from the “embryo” shark (Galeocerdo tigrinus), have been studied. Their component fatty acids are reported.
2. The mixed fatty acids from each of the fats were first resolved into groups of acids of varying unsaturation by the lithium salt acetone and/or lead salt alcohol methods. The methyl esters of each of these groups of acids were fractionated through the Longenecker's E.H.P. column.
3. The two fats are found to belong to the fourth group of Tsujimoto's classification of the Elasmobranch fish liver fats. The “mother” shark liver fat contains 43.3% saturated and 56.7% unsaturated acids. The “embryo” shark liver fat contains 39.1% saturated and 60.9% unsaturated acids. Palmitic acid was about 25% in both of the fats.
4. A possible explanation for the less unsaturation and the absence of higher polyethenoids in the “embryo” liver fat is given.

     

Die prozentuale Zusammensetzung der freien Fettsäuren im Vergleich zum Fettsäuremuster nach Verseifung (Gesamtfettsäuren) bei einigen frischen und gelagerten tierischen Lebensmitteln

Percent Composition of Free Fatty Acids of a Few Fresh and Stored Animal Food Products in Comparison to Their Fatty Acid Pattern after Saponification Depot fat and muscle fat of fresh and stored chickens as well as beef tallow and milk fat were analysed after saponification by gas-liquid chromatography as their methyl esters. The free fatty acids of the same fats were absorbed on alumina and examined for their composition after desorption in the same way. The amount of free fatty acids after lipolysis was not identical with the percentage of fatty acids of the fats. Palmitoleic-, oleic-, and linoleic acid showed an increase, but palmitic and stearic acid a decrease of their amounts in the liberated acids in comparison to the composition of the fatty acids of neutral fats. A remarkable amount of volatile acids could be detected in the free fatty acids only.     

Detection of interesterified fat in hydrogenated fat by lipase hydrolysis and by cooling curve analysis

Porcine pancreatic lipase hydrolysis and Jensen’s cooling curve methods can be adopted for detecting interesterified fat products in a mixture with hydrogenated fats. Lipolysis of interesterified fats shows a relatively greater amount of saturated fatty acids in the 2-monoglycerides in comparison with hydrogenated fats. A similar trend of the distribution pattern of fatty acids also can be noted in a mixture. Interesterified fats do not show any rise in temperature in Jensen’s cooling curve experiment, whereas hydrogenated fats show a distinct rise in temperature. A gradual increase in temperature is obtained for an interesterified fat when it is mixed with increasing content of a hydrogenated fat. On the other hand, hydrogenated fat shows a lowering in the rise of temperature when it is mixed with an interesterified fat. Simultaneous determination of the fatty acid profiles of the 2-monoglycerides and Jensen’s cooling curve characteritics can be utilized in detecting the occurrence of one modified fat in another.     

Effects of Lipid Structure Changed by Interesterification on Melting Property and Lipemia

Interesterification or the randomization reaction changes fatty acid positional distribution and solid fat content of fats, which may consequently affect fat absorption and metabolism. It is well established that saturated fatty acids in the sn‐2 position of triacylglycerols (TAG) have better digestibility and lower postprandial chylomicron clearance compared to those in the sn‐1,3 positions in animal experiments. TAG structure is also shown to affect fasting lipid level and atherosclerosis in animals, but fat interesterification it has been shown to not affect fasting lipid level in human adults. However, its effect on postprandial responses is controversial. In this review, the complex results of studies of interesterification and lipemia were briefly discussed. More importantly, the confounding of two factors that are both changed by interesterification, TAG structure and solid fat content as the main limitation on understanding how interesterification affects lipemia is emphasized. Separation of the two factors is possible using paired fats as demonstrated. This paper also discusses some intriguing effects of fats having saturated fatty acids in the sn‐2 position and the need for future research.     

Dietary fatty acid profile affects endurance in rats

Typically, athletes are advised to increase their consumption of carbohydrates for energy and, along with the general population, to reduce consumption of saturated fats. It is now recognized that fats are not identical in their influence on metabolism, and we argue that the composition of the polyunsaturated fat component should not be ignored. The aim of this study was to manipulate the dietary fatty acid profile in a high-carbohydrate diet in order to investigate the effect of dietary polyunsaturates on submaximal endurance performance in rats. Rats were fed one of three isoenergetic diets containing 22 energy percentage (E%) fat for 9 wk. The diets comprised an essential fatty acid-deficient diet (containing mainly saturated fatty acids); a diet high in n-6 fatty acids, High n-6; and a diet enriched with n-3 fatty acids, High n-3. Submaximal endurance in rats fed the High n-3 diet was 44% less than in rats fed the High n-6 diet (P<0.02). All rats were then fed a standard commercial laboratory diet for a 6-wk recovery period, and their performances were reevaluated. Although endurance in all groups was lower than at 9 wk, it was again significantly 50% lower in the High n-3 group than the High n-6 group (P<0.005). Although n-3 fats are considered beneficial for cardiovascular health, they appear to reduce endurance times, and their side effects need to be further investigated.     

Electrochemical hydrogenation of edible oils in a solid polymer electrolyte reactor. Sensory and compositional characteristics of low Trans soybean oils

Soybean oils were hydrogenated either electrochemically with Pd at 50 or 60°C to iodine values (IV) of 104 and 90 or commercially with Ni to iodine values of 94 and 68. To determine the composition and sensory characteristics, oils were evaluated for triacylglycerol (TAG) structure, stereospecific analysis, fatty acids, solid fat index, and odor attributes in room odor tests. Trans fatty acid contents were 17 and 43.5% for the commercially hydrogenated oils and 9.8% for both electrochemically hydrogenated products. Compositional analysis of the oils showed higher levels of stearic and linoleic acids in the electrochemically hydrogenated oils and higher oleic acid levels in the chemically hydrogenated products. TAG analysis confirmed these findings. Monoenes were the predominant species in the commercial oils, whereas dienes and saturates were predominant components of the electrochemically processed samples. Free fatty acid values and peroxide values were low in electrochemically hydrogenated oils, indicating no problems from hydrolysis or oxidation during hydrogenation. The solid fat index profile of a 15∶85 blend of electrochemically hydrogenated soybean oil (IV=90) with a liquid soybean oil was equivalent to that of a commercial stick margarine. In room odor evaluations of oils heated at frying temperature (190°C), chemically hydrogenated soybean oils showed strong intensities of an undesirable characteristic hydrogenation aroma (waxy, sweet, flowery, fruity, and/or crayon-like odors). However, the electrochemically hydrogenated samples showed only weak intensities of this odor, indicating that the hydrogenation aroma/flavor would be much less detectable in foods fried in the electrochemically hydrogenated soybean oils than in chemically hydrogenated soybean oils. Electrochemical hydrogenation produced deodorized oils with lower levels of trans fatty acids, compositions suitable for margarines, and lower intensity levels of off-odors, including hydrogenation aroma, when heated to 190°C than did commercially hydrogenated oil.     

Analysis oftrans-18:1 isomer content and profile in edible refined beef tallow

Thetrans 18:1 acid content and profile for several samples of edible refined beef tallow were determined monthly over a period of one year. For this purpose, gas-liquid chromatography was combined with silver-ion thin-layer chromatography. The mean content oftrans-18:1 isomers was 4.9±0.9% (n=10) of total fatty acids with a minimum of 3.4% and a maximum of 6.2%. The distribution profile of individual isomers was also established. As in other ruminant fats (milk fat, meat fat), the main isomer is vaccenic (trans-11 18:1) acid. Other isomers, with their ethylenic bonds between positions 6 and 16, were found in lesser amounts. However, some slight but definite differences exist between beef tallow and cow milk fat. The relative proportion of vaccenic acid is higher in the former than in the latter. However, the distribution pattern oftrans-18:1 isomers in beef tallow closely resembles that in beef meat fat (lean part).     

Qualitative und quantitative Untersuchung der freien Fettsäuren in Depotfetten und fetthaltigen Erzeugnissen

Qualitative and Quantitative Investigation of Free Fatty Acids in Depot Fats and Fat-Containing Products The free fatty acids (FFA) in the fat of dry sausages were adsorbed on aluminia. After elution the methylesters of the fatty acids were separated on Reoplex (400). The composition of fatty acids released from fats showed distinct differences to the composition of a fat after saponification. Myristic, palmitoleic and linoleic acid had increased in the amount expressed as percentage of fatty acids while the percentage of stearic and possibly palmitic acid had decreased in concentration. The volatile fatty acids (<14 C) increased in the fat of dry sausages, too.     

Characterization of Aroma-Active Compounds in Iranian cv. Mari Olive Oil by Aroma Extract Dilution Analysis and GC–MS-Olfactometry

Aroma, aroma‐active compounds and fatty acid profiles of Iranian olive oil obtained from the cv. Mari were investigated for the first time in the current study. Aroma extracts were isolated from the oil by using a purge and trap extraction system and their compositions were analyzed by gas chromatography‐mass spectrometry‐olfactometry (GC–MS‐O). A total of 35 aroma compounds comprising alcohols, aldehydes, acids, esters, ketones, terpenes and volatile phenols were identified and quantified in the assayed samples. Aldehydes were present at the highest levels, followed by ketones and alcohols. (E)‐2‐Hexenal was quantitatively (1589 µg kg^?1) the main aroma compound in the analyzed oils, followed by hexanal and (E)‐2‐heptenal. The aroma‐active volatiles were elucidated in the aromatic extract by applying aroma extract dilution analysis (AEDA). The results of AEDA revealed 17 aroma‐active compounds. Under these condition it was possible to completely identify 16 of these compounds. Regarding to the flavor dilution (FD) factor, the most potent odorants with the highest FD factor were (E)‐2‐hexenal (512), followed by hexanal, 6‐methyl‐5‐hepten‐2‐one, (E)‐2‐decenal and one unknown compound (LRI = 1871). The fatty acid profile of the tested oils was composed of thirteen compounds. Oleic acid was the main fatty acid (76.01 %) followed by palmitic acid.     

Studies on effects of dietary fatty acids as related to their position on triglycerides

This article reviews published literature on how the stereospecific structure of dietary triglycerides may affect lipid metabolism in humans. Animal studies have shown enhanced absorption of fatty acids in the sn-2 position of dietary triglycerides. Increasing the level of the saturated fatty acid palmitic acid in the sn-2 position (e.g., by interesterification of the fat to randomize the positions of the fatty acids along the glycerol backbone) has been shown in rabbits to increase the atherogenic potential of the fat without impacting levels of blood lipids and lipoproteins. In contrast, enhancing the level of stearic acid in the sn-2 position has not been found to affect either atherogenic potential or levels of blood lipids and lipoproteins in rabbit. Fatty acids other than palmitic and stearic have not been studied systematically with respect to possible positional effects. A limited number of human studies have shown no significant effects of interesterified fats on blood lipid parameters. However, it is unknown whether modifying the stereospecific structure of dietary triglycerides would affect atherogenicity or other long-term health conditions in humans. It is possible that incorporation of palmitic acid into the sn-2 position of milk fat is beneficial to the human infant (as a source of energy for growth and development) but not to human adults. Additional research is needed to determine whether processes like interesterification, which can be used to alter physical parameters of dietary fats (e.g., melting characteristics), may result in favorable or unfavorable long-term effects in humans.     

Effects of milk fat replacement by PUFA enriched fats on n‐3 fatty acids,conjugated dienes and volatile compounds of fermented milks

A study was carried out to determine the profiles of fatty acids in fermented milks and dairy derivatives made with milk fat substituted by polyunsaturated fatty acid (PUFA)‐enriched fat. In order to improve the organoleptic properties of those products, whey protein concentrates (WPC) were added during the manufacturing process. Interest was focused during manufacturing and storage period on the contents of “healthy” fatty acids, mainly conjugated linoleic acid and n‐3 PUFA. Contents of these fatty acids were not affected by the manufacture practices and neither did addition of WPC during manufacturing nor cold storage cause their decrease. Percentages of total n‐3 fatty acids in fat from dairy derivatives enriched in PUFA after 21 d of storage (1.45%) were very close to those obtained before processing (1.39%). Contents did not differ either substantially when WPC were added during manufacturing (1.46%). The increase of volatile compounds was also examined. Although a slight decrease in the total volatile content was observed, percentages of different compounds were not modified when milk fat was substituted by PUFA enriched fat.     

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.     

Einfluß von Futterfetten auf die Qualität tierischer Veredlungsprodukte

Effects of Feed Fats on Quality of Animal Product At the same level of energy supply intake of fats/oils do not lead to a higher fat deposition in the carcass. Additionally, fats are carrier of fat soluble vitamins A, D, E, K and improve their absorption from the intestinal tract. The fatty acid profile of fat deposited in the organism, as for example in egg yolk is influenced by the intake of fatty acids provided by feed. This especially concerns linoleic- and linolenic acid as well as lauric- and myristic acid, High contents of polyunsaturated fatty acids negatively influence oxidative stability as well as consistency of body fat and therefore quality of animal products. An improved oxidation protection can be carried out by supplementation of antioxidants. Medium-chain, saturated fatty acids reveal positive effects on both criteria.     

Detection of interesterified fats in hydrogenated fats

Interesterification of fats is being used increasingly as an alternative to hydrogenation in preparing shortening and margarine bases. The detection of interesterified fats in vanaspati (a hydrogenated fat) is relevant because of possible adulteration problems. Either palmitic acid-rich or stearic acid-rich interesterified fats were blended with 13 market samples of hydrogenated fat (vanaspati) and examined by on-plate lipase hydrolysis of glycerides, gas chromatographic determination of fatty acids of the isolated 2-monoglycerides and calculation of two emperical indices. These were R₁, the ratio of the amounts of palmitic acid present in the 2-position to that in the total glyceride, and R₂, the ratio of saturated acid present in the 2-position to total saturated fatty acid in the fat. The vanaspati, R₁ was always below 10 and R₂ was always below 20. The presence of 5–10% interesterified fat raised both figures and offered a suitable basis for the detection of interesterified fats in hydrogenated fats.     

Gaschromatographische Analyse des Samenfettes der mittelamerikanischen Fevillea cordifolia (Cucurbitaceae)

Gaschromatographic Analysis of the Seed Fat of the Middle American Fevillea cordifolia (Cucurbitaceae) The fat of the seeds of Fevillea cordifolia was extracted under exclusion of oxygen and light and then characterized by ¹³C-NMR in regard to the contained unsaturated acid moieties. The total fat was separated by HPLC to yield one major fraction (? 45%), one medium fraction (? 18%) and some minor fractions. All substantial fractions showed the chromophore of a conjugated triene. According to MS-analysis the major fraction consists of distearyleleostearylglycerol. The total fat was converted by transesterification to a mixture of fatty acids methyl esters, which was analyzed by subsequent HPLC and GC: Main fatty acids were found to be stearic acid (53%) and the triple conjugated α-eleostearic acid (31%). Interestingly, punicic acid, which is isomeric to α-eleostearic acid and contained in various seed fats of Cucurbitaceae plants, could not be detected.