Dilatometric investigations of fats II. Dilatometric behavior of some plastic fats between 0° C. and their melting points

Summary 1. Dilatometric curves between 0°C. and their melting points have been obtained for the following fats: lard, butterfat, cottonseed oil, peanut oil, a commercial margarine oil, a commercial all-hydrogenated vegetable shortening, three samples of soybean oil hydrogenated to different degrees, a hard butter fractionally crystallized from hydrogenated peanut oil, a mixture of tristearin and soybean oil, and a synthetic fat containing equal molar proportions of stearic and oleic acids. 2. The dilatometric curves, of volume change in the fat against temperature, were in every case composed of a series of straight lines, separated by sharp breaks or transition points. 3. The number of linear sections in the dilatometric curves corresponded in a general way with the known degree of complexity in the glycerides of the fats, and varied from two in the case of the relatively simple stearic-oleic glyceride mixture, to at least seven in the case of the all-hydrogenated shortening. Since each break in the curve must correspond to the disappearance of a distinct class of solid glycerides or glyceride complexes, the application of dilatometry to the qualitative and quantitative determination of glyceride composition in fats is suggested. 4. Only two of the fats examined, the mixture of tristearin and soybean oil, and the synthetic stearicoleic glyceride mixture, exhibited polymorphism, even after rapid solidification in ice water. Presented before the American Oil Chemists’ Society Meeting, New Orleans, Louisiana, May 10 to 12, 1944. This is one of four regional research laboratories operated by the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

The Effects of High Levels of Fats Rich in Erucic Acid (from Rapeseed Oil) or Cetoleic and Cetelaidic Acids (from Partially Hydrogenated Fish Oil) in a Short-Term Study in a Non-Human Primate Species I

Three experimental groups of primates (cynomolgus monkeys Macaca fascicularis) were adapted to high-fat diets and maintained on the diets for four months. One group (control) was fed a diet containing 25% of lard and corn oil in a 3 : 1 mixture and the other groups received either 25% of rapeseed oil or of partially hydrogenated herring oil. Docosenoic acids were approximately 25% of the rapeseed oil (as erucic acid) and of the partially hydrogenated herring oil (as a mixture of cetoleic acid and cetelaidic acid). Monitoring of physiological parameters did not reveal any important differences between groups. Fecal fatty acids and depot fatty acids showed differences in details of composition from the fatty acids in the diets. These are discussed in terms of intestinal microorganism activity, absorption processes, and in vivo alterations in the primates. In the two experimental groups skeletal and cardiac muscle showed lipidosis. This was especially evident in the apexes of the hearts of animals fed the rapeseed oil and partially hydrogenated herring oil. Fatty acid details from depot fat and cardiac apex triglycerides showed differences and further differences were discerned among the isomeric docosenoic and eicosenoic acids of the cardiac triglycerides. The histopathology of the primate hearts showed a few mild foci of inflammation in all groups which could not be associated with diet, whereas the same diets fed to male weanling rats induced the severe necrotic lesions widely associated with such diets. It is concluded that different species of animals show physiologically different responses to fat-based dietary factors and that further experiments with primates and with oils containing docosenoic acids are required to determine what, if any, cardiac problems exist.     

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.     

Essential fatty acid-deficient rats: I. Growth and testes development

Partially hydrogenated oils as the sole dietary fat enhances the development of essential fatty acid (EFA) deficiency in young rats. Partially hydrogenated herring oil (HHO) caused total impairment of the spermatogenic tissue after five weeks of experiment, while partially hydrogenated arachis oil (HAO) caused severe degeneration of this tissue in 15 weeks. A fat-free diet caused degeneration in 26 weeks. In the dietary fats, the total content oftrans acids, calculated as elaidic acid, was 47% and 23% in HAO and HHO, respectively. Further, varying amounts of different positional isomeric fatty acids were also present in the partially hydrogenated oils. Besides the specific tissue changes, poor growth, poor feed efficiency and skin signs characteristic of EFA deficiency were noticed. On the other hand, partially hydrogenated soybean oil (HSO) as the sole dietary fat kept the animals normal in all respects. this oil still contained 32% linoleic acid; the total content oftrans acids amounted to 11%, calculated as elaidic acid.     

The effect of various dietary factors on the size distribution of lymph fat particles in rat

By means of cellulose acetate electrophoresis and measurement of radioactivity, lipoproteins (d≤1,006) of lymph collected from rats fed a diet containing fats added to labeled fatty acids for 20–24 hr, have been separated into two kinds differing in their size. Fats with different saturated and unsaturated fatty acid content were tested: corn oil, lard, mutton tallow, tripalmitin, corn oil-lard mixture, and randomized palmitic-linoleic triglycerides. Factors studied were: (a) increased amounts of these fats given alone or included in a test meal; (b) added amounts of nutrients (other than fats) in the test meal; (c) adaptation to a diet containing 20% fat for 10 days. The major part of the labeled lymph lipid was always transported by the smaller particles. Size distribution of lymph fat particles was influenced by some of the factors studied. Generally, unsaturated fats produced higher amounts of larger particles.     

Essential fatty acid contents of various fats: Interpretations of values by physico-chemical tests

Biological assays of oil and fat products, free from isomers of the naturally-occurringcis-9,cis-12 linoleic acid, have been shown to provide estimates of essential fatty acid content which agree well with values obtained by spectrophoto-metric analysis. However, when partially hydrogenated fats, such as those used in margarines, are bio-assayed the estimates obtained are only about 60% of those derived by spectro-photometric tests. In a blended corn oil margarine, good agreement was obtained for linoleic acid content by using biological assay or spectrophotometry, thio-cyanometric procedure, column chromatography for saturates plus iodine value, and gas liquid partition (GLP) chromatography. This margarine fat contained about 29% of the essential form of linoleic acid, and had a ratio to saturated fatty acids of 1.6:1. The hydrogenated corn oil margarine is unlike conventional margarines in providing high amounts of the isomeric forms of linoleic acid which lack essential fatty acid activity. For this reason, poor agreement was obtained between biological assay results and those by physico-chemical measurements of linoleic acid content. Such fat contains only about 6% of the essential form of linoleic acid, with a ratio to saturated fatty acids of ca. 0.3.1. From this study it is now possible to characterize, even without bio-assay data, the fatty acid composition of a highly isomerized fat, such as is found in hydrogenated corn oil margarine. The characterization groups the fatty acids into saturates and total linoleic acids, with the latter including estimates of the positional isomers of linoleic acid with widely spaced double bonds,trans forms of linoleic acid with methylene-in-terrupted double bonds, linoleic acids with the double bonds in conjugated position, andcis-9,cis-12 linoleic acid. The combined use of the spectrophotometric and thiocyanometric procedures makes it possible to estimate the essential fatty acid content of hydrogenated fats containing residual dienes.     

Influence of elaidate and erucate on heart mitochondria

Male, weanling rats were fed, for up to six weeks, corn oil (CO), rapeseed oil (RSO), partially hydrogenated fat (HF), or a mixture of partially hydrogenated fat and corn oil (HF+CO). The respiratory activity of their isolated heart mitochondria, their hormone-sensitive lipase activity, and the fatty acid compositions of the phospholipids of the mitochondria were determined. The results indicated that heart mitochondria isolated from rats which had been fed corn oil (CO) had a higher rate of oxygen uptake, showed higher respiratory control ratios, higher ADP/0 ratios and a higher rate of ATP synthesis than the heart mitochondria isolated from those fed rapeseed oil or hydrogenated fats. The oxygen uptake rates of the rat heart mitochondria isolated from each dietary group of rats was in order: oleyl carnitine ≫ erucyl carnitine > elaidyl carnitine. The decreased capacity to oxidize substrate by heart mitochondria which had been isolated from the hearts of rats fed rapeseed or hydrogenated soybean oil as compared with those fed corn oil as a sole source of dietary fat seemed related to the mitochondria lipid composition. The type of dietary fat fed had a pronounced influence on the mitochondrial fatty acid compositions of phosphatidylcholine, phosphatidylethanolamine, and cardiolipin. The lipase activity of the RSO-fed group did not show any increment with either epinephrine or supplemental ATP treatment. The substrate preference for lipase activity in myocardium was corn oil-triglycerides > trierucin > trielaidin > tripalmitin. However, cardiac lipid accumulation did not seem related to lipase activity in the myocardium. Taken from a thesis submitted by Chi Ming Lee Hsu in partial fulfillment of the Ph.D. degree in Food Science, University of Illinois at Urbana-Champaign.     

Effect of Interesterified Fats and Isolated trans Fatty Acids on Serum Lipid Classes in Cholesterol-Bile Salt Stressed Rats

Interesterified plastic fat products based on a) sal fat and groundnut oil (30: 70, w/w;P/S,0.8) (sal-GNO);b) vanaspati, partially hydrogenated vegetable oil and groundnut oil (40:60; P/S, 1.0; isolated trans fatty acid content 17%) (vanaspati-GNO);c) cottonseed oil (P/S, 1.5) (CSO) and d) sal fat and safflower oil (50:50, P/S, 1.3) (sal-saff) were prepared using dry sodium methoxide as the catalyst. The products had slip points of 33?34°C. These products, their original blends, safflower oil (P/S, 8.5) and a blend of vanaspati and safflower oil (50 : 50, P/S, 2.8 and isolated trans fatty acid content 22%) (vanaspati-saff) were tested for hypolipidaemic effect (serum total cholesterol, total lipids, triglycerides and phospholipids) in cholesterol-bile salt stressed rats. All the test fats having linoleic acid content varying from 21.9-76.6% and P/S ratio from 0.8 to 8.5 and fed at 10% level providing 23% calorie were found to be superior to vanaspati (P/S, 0.16, 3% linoleic, 43% isolated trans fatty acids). P/S ratio of 1.5 and linoleic content of 30% in fat were found to be optimum for maximum hypolipidaemic effect at above dietary regimen. Fat and cholesterol contents of liver of animals, fed test lipids were significantly lower than that of animals fed vanaspati. when linoleic acid content of the product was comparatively low (e.g. sal-GNO, 25%), the process of rearrangement reduced the cholesterol content of liver. With high linoleic acid content (CSO, 48.2% or sal-saff, 40.4%) interesterification was without any effect. Hypolipidaemic effect of interesterified products was similar to that observed with original materials. Thus, the above quality of a fat having characteristics within the above ranges does not depend upon the distribution of acyl groups in glyceride molecules. Isolated trans fatty acids behaved more or less like a saturated fatty acid in elevating serum lipids. Vanaspati was found to be highly hyperlipidaemic.     

The deposition of polyunsaturated fatty acids in the rat fed partially hydrogenated vegetable oil

The composition of deposited polyenoic fatty acids in rats fed liquid or partially hydrogenated corn oil was determined by gas chromatography, which did not distinguish isomeric forms, and by lipoxidase which reacted with thecis, cis-methylene-interrupted acids. The two methods gave similar results for the liver fatty acids of rats fed either the unhydrogenated or partially hydrogenated oil. Of the fatty acids from the epididymal fat pads of rats fed the hydrogenated product, an appreciable quantity of linoleate isomers did not react with lipoxidase. The total amount of linoleic acid deposited was related to the total fatty acid pattern of the dietary oil. It appeared that thetrans-acids were mostly metab-olized and that the originalcis,cis-linoleic acid remaining in the partially hydrogenated product was preferentially incorporated into tissues. One of 10 papers to be published from the Symposium “Hydrogenation” presented at the AOCS Meeting, New Orleans, April 1970.     

Dietary polyunsaturated fat in relation to mammary carcinogenesis in rats

High fat diets promote the development of mammary tumors induced in rats by 7,12-dimethylbenz(a)anthracene (DMBA), and polyunsaturated fats are more effective than saturated fats. This difference is related to the linoleic acid content of polyunsaturated vegetable oils, but the amount of linolealte required for maximum tumor promotion appears to be higher than indicated by earlier experiments. Comparison of the effects of a polyunsaturated vegetable oil (corn oil) containing linoleate with a fish oilo (menhaden oil) containing polyunsaturated fatty acids derived from linolenic acid showed that higher dietary mammary tumors, while corresponding levels of menhaden oil had an inhibitory effect. This is further evidence that promotion of mammary tumorigenesis by polyunsaturated vegetable oils may be mediated by prostaglandins or other biologically active eicosanoids derived from n−6 fatty acids.     

Dietary fat composition influences fatty acid composition of milk fat globule membrane in lactating cows

Milk fat globule membranes are derived directly from the apical plasma membrane of mammary epithelial cells. To evaluate the effect of dietary fat on mammary membranes, we determined the fatty acid composition of the milk fat globule membrane in lactating dairy cows fed diets supplemented with fats of different fatty acid composition, or infused intravenously with soy oil emulsion. A preliminary survey, using an abbreviated preparation procedure (membranes isolated at 48,000 x g-max for 15 min), yielded about 45% of the total membrane fatty acids that could be recovered by centrifuging at the same speed for 120 min, and showed that changes in fatty acid composition of membranes reflected dietary fatty acids to some extent. Dietary palmitic acid increased the content of 16:0 in the membranes. A high corn diet increased ruminal formation of t18:1, and its level increased to 12% of membrane fatty acids. Infusion of soy oil emulsion increased 18:2 membrane content, and decreased the levels of 18:1 and 20:4. All treatments decreased the ratio of unsaturated/saturated fatty acids as compared to controls, whereas the ratio of polyunsaturated/saturated fatty acids was increased by feeding a high corn diet or by infusing soy oil. The ratio of 18:2/c18:1 increased from 0.31 to 1.0 after infusing soy oil for 4 days. The fatty acids of membranes isolated upon 120-min centrifugation were slightly more saturated. The differences were not sufficiently large, however, to affect overall results significantly.     

Die Verdauung von Speisefetten mit Pankreaslipasen und ihre Beeinflussung durch das Fettsäuremuster

The Influence of Fatty Acids in Triglycerides on the Digestion of Dietary Fats by Pancreatic Lipase The digestion of dietary fats by pancreatic lipase was studied in in-vitro-experiments. We tested the following fats: coconut, butterfat, cocoabutter, lard and oil of corn germ. The breakdown of triglycerides was followed up by monitoring the free fatty acids and glycerol. Additionally we analyzed the fatty acid distribution by gas-liquid chromatography of triglycerides, 1,2-diglycerides and 2-monoglycerides. Fatty acids with a chain length from C₁₀C₂₀ were determined by gas chromatography. Short chain fatty acids were not regarded separately. As pancreatic lipase has a positional specificity for the 1- and 3-position of a triglyceride there is information on the distribution of fatty acids in fats and of their digestion by such experiments. For the resorption of the fatty acids it may be of a certain importance in which position it is esterified in the fat when it is hydrolysed in gut. The hydrolysis of fats used in these experiments was quite different. This can be explained by the fatty acid distribution, the chain length and by a varying rate of emulsification of fats in an aqueous phase.     

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.     

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.     

Dietary fat and colon cancer: Animal model studies

Since it was first suggested that high dietary fat is a risk factor in colon cancer, there have been several studies to test this hypothesis. Epidemiologic studies suggested a positive association between dietary fat and colon cancer. Laboratory animal model studies demonstrated that not only the amount of rat, but also types of fat differing in fatty acid composition are important determining factors in colon tumor development. Chemically-induced colon tumor incidence was increased in rats fed the semipurified diets containing 23% corn oil, safflower oil, lard or beef tallow (high-fat) as compared to those fed 5% corn oil, safflower oil, lard or beef tallow diets (low-fat). Diets containing 23% conconut oil, olive oil or fish oil, or high-fat diets containing varying levels oftrans fat, had no colon tumor-enhancing effect compared to their respective low fat diets. The stage at which the effect of dietary fat is exerted appears to be mostly during the post-initiation phase of colon carcinogenesis. Lack of a colon tumor enhancing effect of dietary fish oil is observed both during the initiation and postinitiation phases. The mechanisms by which various dietary fats increase colon carcinogenesis are not fully understood. In most instances, however, the high-fat diet appears to enhance tumorigenesis through elevation of agents, such as secondary bile acids, that act as promoters of tumor development. Lack of colon tumor promotion by dietary fish oil andtrans fat appears to be mediated through their effect on mucosal ornithine decarboxylase activity, colonic secondary bile acids and/or prostaglandin synthesis. Based on a paper presented at the Symposium on Lipids in Cancer held at the AOCS Annual Meeting, Baltimore, MD, April 1990.     

Biliary and fecal steroid excretion in rats fed partially hydrogenated soybean oil

Male Wistar rats were fed cholesterol-free or cholesterol-enriched diets containing partially hydrogenated soybean oil with different levels of trans-fatty acids or unhydrogenated soybean oil at the 10% level. The linoleic acid content of hydrogenated fat diets was adjusted to 3.6% of the total energy. Hydrogenated fat diets contained 29% and 41% trans-acids, mainly as t-18:1. Trans-fats exerted no untoward effects on growth parameters, but increased liver weight. Dietary hydrogenated fats influenced neither the concentration nor composition of biliary steroids, irrespective of the presence or absence of cholesterol in the diet. In rats fed a cholesterol-free diet, daily fecal output of neutral and acidic steroids was enhanced by hydrogenated fats and the magnitude of augmentation was proportional to the dietary level of trans-fatty acids. The increased fecal steroid excretion corresponded to an increase in total excreta. Hydrogenated fats also tended to enhance bile acid excretion when feeding a cholesterol-enriched diet. The results suggest that dietary trans-fatty acids, in relation to cis-polyunsaturated fatty acids, provoke demonstrable change in steroid homeodynamics.     

Influence of medium-chain triglycerides on lipid metabolism in the rat

Lipid metabolism was studied in rats fed diets containing corn oil, coconut oil, or medium-chain triglyceride (MCT), a glyceride mixture containing fatty acids of 8 and 10 carbons in length. The ingestion of MCT-supplemented, cholesterolfree diets depressed plasma and liver total lipids and cholesterol as compared with corn oil-supplemented diets. In rats fed cholesterol-containing diets, plasma cholesterol levels were not influenced by dietary MCT, but liver cholesterol levels were significantly lower than in animals fed corn oil. In vitro cholesterol synthesis from acetate-1-¹⁴C was lower in liver slices of rats that consumed MCT than in similar preparations from corn oil-fed rats. Studies of fatty acid carboxyl labeling from acetate-1-¹⁴C and the conversion of palmitate-1-¹⁴C to C₁₈ acids by liver slices showed that chain-lengthening activity is greater in the liver tissue of rats fed MCT than in the liver of animals fed corn oil. The hepatic fatty acid desaturation mechanisms, evaluated by measuring the conversion of stearate-2-¹⁴C to oleate, was also enhanced by feeding MCT. Adipose tissue of rats fed MCT converts acetate-1-¹⁴C to fatty acids at a much faster rate than does tissue from animals fed corn oil. Evidence is presented to show that the enhanced incorporation of acetate into fatty acids by the adipose tissue of rats fed MCT represents de novo synthesis of fatty acids and not chain-lengthening activity. Data are also presented on the fatty acid composition of plasma, liver, and adipose tissue lipids of rats fed the different fats under study.     

Species variation in the atherogenic profile of monkeys: Relationship between dietary fats,lipoproteins, and platelet aggregation

Because lipoproteins and platelet aggregation have been implicated in atherogenesis, relative differences in the response of these variables to dietary fat saturation were compared in three species of monkeys differing in their susceptibility to atherosclerosis (cebus, rhesus, and squirrel monkeys). Both long-term (8–12 years) and short-term (8 weeks) responses to diets containing 31% fat calories were examined in the same monkeys. As expected, long-term feeding of coconut oil by comparison to corn oil produced significantly higher plasma concentrations of total cholesterol, LDL cholesterol, apoB, and triglycerides, as well as higher ratios of LDL/HDL cholesterol and apo B/apo A-I. These responses were characteristic of all species with cebus being most responsive and rhesus the least. The shortterm plasma cholesterol response to animal fats (butter, lard, beef tallow) was significantly less than that to coconut oil. When fish oil was substituted for two-thirds of either corn oil or coconut oil, exceptional decreases occurred in plasma cholesterol and triglycerides, as well as in HDL cholesterol and apo A-I concentrations despite the fact that the fish oil diets contained more saturated fat and less polyenes than the corn oil diet. Platelet aggregation tended to increase with saturated fat consumption and greatly decreased with fish oil intake in all monkeys, although cebus monkeys were ten-fold more resistant to platelet aggregation than the other two species. The molecular species of platelet phosphatidylcholine (PC) varied with both the dietary fat fed and species of monkey. An inverse correlation (r=−0.60; p<0.001) was found between changes in one such PC molecular species (18∶0−20∶4) induced by diet and the platelet aggregation threshold. These results demonstrate that the lipemic and platelet responses to dietary saturated fat depend upon both the type of fat (i.e., the specific combination of dietary fatty acids, including the chain length of saturated fatty acids and the degree of polyunsaturation) and the species of monkey (genetic component) in which the response is elicited.     

The preparation of polyglycerol esters suitable as low-caloric fat substitutes

Medicinal research has linked dietary fats with such maladies as cancer, heart disease and stroke. The overconsumption of fats has been declared one of the major dietary health concerns in the United States by the Surgeon General. As a result, there is an increased awareness by consumers of their need to reduce the intake of calories derived from fat. The food industry has shown much interest in the development of substitutes for dietary fats and oils. To date, no substitute that can be used as a full fat replacement has entered the marketplace. Linear polyglycerols (LPGs) have been prepared by a proprietary polymerization process. Fatty acid esters prepared from LPGs were found to resist hydrolysis by digestive enzymes and were poorly absorbed in animal feeding tests. When esterified with fatty acids, LPG esters are similar to natural triglycerides in color, odor, taste and other physical characteristics. These properties make LPG oils good candidates for use in nonnutritive edible oil applications, particularly in uses that require stability at high temperatures.     

Studies in the Glyceride Composition of Partially Hydrogenated Rearranged Glycerides of Cottonseed Oil

The directed rearrangement reaction in solvents of partially hydrogenated cottonseed oil was investigated with special reference to the influence of polarity of solvents and amount of trisaturated glycerides formed. The results as obtained by selective enzymatic hydrolysis, gas liquid chromatography and infrared spectrophotometry of the whole fat triglycerides and of the corresponding monoglycerides of cottonseed oil and partially hydrogenated cottonseed oil, before and after directed interesterification, indicate a general trend of the increase of the saturated fatty acyl radicals in the 2-position of the glyceride moiety with the corresponding decrease of the unsaturated acids. The considerable decrease in the concentration of cis unsaturated acid in the 2-position of the triglycerides of partially hydrogenated cottonseed oil has been observed after the directed rearrangement reaction with the simultaneous enrichment of trans unsaturated acid. It was also observed that cottonseed oil does not show any plasticity, whereas after directed interesterification it shows remarkable plasticity. The plasticity of partially hydrogenated cottonseed oil is further diminished after directed rearrangement reaction.