Dietary fat and heart disease

Summary So far as the industry is concerned, the evidence indicating a relationship of dietary fat to heart disease presents some interesting challenges. Undoubedly it portends a change in the fat cousumption pattern toward a lowerper capita use coupled with a shift from solid fats toward a higher proportion of edible oils. Most important of all, however, is the growing recognition that fats and oils are nutritionally valuable foods, intimately related to health and well-being, and should by no means be regarded merely as a source of calories. Although there are innumerable factors involved in the etiology of heart disease, dietary fat is an important one and fortunately is one that can be modified in whatever way proves desirable. Because the more saturated types of fats lead to higher serum cholesterol levels than do the polyunsaturated oils, and because cholesterol is somehow involved in the course of atherosclerotic heart disease, clinical tests are now in progress to determine whether prolonged use of a diet rich in these oils will lead to fewer heart attacks than does the usual American diet rich in saturated fats. So far, data are encouraging enough to merit recommendation of the modification in dietary fat to the coronary-prone individual and to justify development of new high-linoleate fat products by the industry.     

Fatty acid contents of certain processed foods

Summary Fatty acid constituents of two cheeses, four cured meats, and two hydrogenated oils were determined; two sets of data were obtained for each sample. Unsaturated acids were determined spectrophotometrically in the total fatty acids prepared from each fat, and saturated and unsaturated components were determined chemically and spectrophotometrically on each fraction obtained from distilling the methyl esters prepared from the fats. Close agreement was obtained between the percentages of unsaturated components found in distilled and non-distilled samples. Methyl esters of cheese fats were prepared without prior distillation of steam-volatile acids; no separation of saturated and unsaturated components was made on any sample. Fatty acid components were also converted to percent of each fatty acid in each food. This research was supported in part by the U. S. Department of Agriculture through a contract sponsored by the Bureau of Human Nutrition and Home Economics.     

Studies on Nutritional Quality of Interesterified Fat Products

The nutritional quality of the fat products with melting range 36° to 37°C having been prepared from non-traditional oils like mowrah (Madhuca latifolia), ricebran (Oryzasativa) containing sal (Shorea robusta) and cottonseed (Gossypium hirstum) mixed with sal by interesterification (randomisation) were examined with rats and compared with that of “Vanaspati”, produced by hydrogenation of mixtures of liquid oils and used exclusively as a substitute of ghee (butter fat) in India. The average food intake, body weight gain, food efficiency ratio, weight of different organs, total lipid content of serum, liver, heart and kidney were similar in all the cases. Serum triglyceride levels were quite low in case of interesterified fats fed rats though total and free cholesterol levels were not significantly different. Serum phospholipid levels were slightly higher in case of the interesterified fats fed rats. Total and free cholesterol, phospholipid and triglyceride content of liver, kidney and heart were similar for the four dietary groups of rats. Serum lipids and liver lipids contain more polyunsaturated fatty acids when rats were raised on various interesterified fats in place of hydrogenated fat product “Vanaspati”.     

食品乳化剂柠檬酸甘油单,二酸酯的合成

采用以乙酸为溶剂,柠檬酸和单甘酯进行酯化反应合成了质量指标均符合ＦＡＯ／ＷＨＯ标准的柠檬酸甘油单,二酸酯,确定了合成的最佳工艺条件,并以此为原料配制了两种在常温下呈液态的复合型搞氧剂。试验结果表明,其抗氧化效果超过了国外同类产品,在油脂及含油食品中具有广泛应用价值。     

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.     

Nutritional studies of polyglycerol esters

Palatable polyglycerol esters of various mol wt were prepared with fatty acids from cottonseed and peanut oils. The wt gains of weanling male rats fed 1 g/day polyglycerol esters in 5 g of a basic diet were compared with those of matching rats fed 1 g, 0.5 g, and no lard in 5 g basic diet. After three weeks, all rats were given free access to diets containing 8% polyglycerol esters or lard. The polyglycerol esters were utilized as well as lard for wt gain. Intestinal absorption of the fatty acids from the polyglycerol esters was the same as with lard. Autopsies and histological examination of the tissues revealed no abnormalities attributable to the consumption of these materials. Appearance of the animals was normal throughout the experiment. The epididymal fat of the animals was similar regardless of the polyglycerol structure fed. No polyglycerols were detected in the body fat. From these results, it is concluded that the polyglycerol esters of both low and high mol wt were nutritionally similar to naturally occurring fats and that they were nontoxic. Presented at the AOCS Meeting, Atlanta, 1963. Deceased.     

International

Summary The consumption of edible fats and oils in Korea is expected to reach 600,000 MT, a three-fold increase, in 10 years from 1979 to 1989. Even if the best efforts are applied to increasing the production of indigenous oil resources such as rice bran, rapeseed, sesame, perilla, peanut, and soybean, the dependence on imported fats and oils (about 80%) likely will continue. The rapid increase in consumption of edible fats and oils in future will certainly warrant intensified research efforts related to fat and oil production and consumption. The following report was prepared for JAOCS by Dong Hoon Kim, professor of food chemistry, Department of Food Technology, Korea University, Seoul. Dr. Kim has been a member of the AOCS since 1976.     

Fatty alcohols in capelin,herring and mackerel oils and muscle lipids: II. A comparison of fatty acids from wax esters with those of triglycerides

The fatty acids recovered from the triglycerides and wax esters of common northwest Atlantic copepods are compared with the fatty acids of wax esters recovered intact from certain fish skin and body lipid, and from commercial fish oils. The fish species, herring, capelin and mackerel, all feed on copepods, and many resemblances of the copepod lipid fatty acids to those of a previous analysis of similar copepods suggest that the basic dietary fat input for these fish may be quite constant. The two copepod fatty acid analyses differed quantitatively in triglyceride 20∶1 and 22∶1 and also in 20∶5ω3 and 22∶6ω3, confirming the primary role of the wax esters in copepods. Selectivity factors are discussed in comparing the copepod wax ester fatty acids with the fatty acids of the wax esters recovered intact from the fish lipids and oils. The basic role of copepods in supplying all types of fatty acids to fish depot fats is considered to be strongly supported by these findings.     

Biodiesel processing and production

Biodiesel is an alternative diesel fuel that is produced from vegetable oils and animal fats. It consists of the monoalkyl esters formed by a catalyzed reaction of the triglycerides in the oil or fat with a simple monohydric alcohol. The reaction conditions generally involve a trade-off between reaction time and temperature as reaction completeness is the most critical fuel quality parameter. Much of the process complexity originates from contaminants in the feedstock, such as water and free fatty acids, or impurities in the final product, such as methanol, free glycerol, and soap. Processes have been developed to produce biodiesel from high free fatty acid feedstocks, such as recycled restaurant grease, animal fats, and soapstock.     

Effect of dietary palm oil and its fractions on rat plasma and high density lipoprotein lipids

Male Sprague Dawley rats were fed semipurified diets containing 20% fat for 15 weeks. The dietary fats were corn oil, soybean oil, palm oil, palm olein and palm stearin. No differences in the body and organ weights of rats fed the various diets were evident. Plasma cholesterol levels of rats fed soybean oil were significantly lower than those of rats fed corn oil, palm oil, palm olein or palm stearin. Significant differences between the plasma cholesterol content of rats fed corn oil and rats fed the three palm oils were not evident. HDL cholesterol was raised in rats fed the three palm oil diets compared to the rats fed either corn oil or soybean oil. The cholesterol-phospholipid molar ratio of rat platelets was not influenced by the dietary fat type. The formation of 6-keto-PGF_1α was significantly enhanced in palm oil-fed rats compared to all other dietary treatments. Fatty acid compositional changes in the plasma cholesterol esters and plasma triglycerides were diet regulated with significant differences between rats fed the polyunsaturated corn and soybean oil compared to the three palm oils.     

Alkali isomerization—Gas chromatography with the microreactor apparatus

A simple and rapid method of simultaneously conjugating polyunsaturation and forming methyl esters from triglyceride oils, other esters and fatty acids has been developed by using the microreactor apparatus (MRA). These reactions occur while a mixture of tetramethylammonium hydroxide and sample of fat is being injected into a gas chromatograph from the MRA reaction chamber. The speed of this microanalysis is limited only by peak elution and peak integration times. Analyses of soybean oil and six partially hydrogenated fats have been compared with those previously obtained by the alkali isomerization spectrometric method. The amount of conjugation that occurs during the reaction is a measure of the linoleic acid in the oil. This procedure should prove useful for rapid microscale analysis of conjugatable dienes in a variety of samples, including edible fat products. Presented at the Fall ISF-AOCS Meeting, Chicago, September 1970. No. Market. Nutr. Res. Div., ARS, USDA.     

Applicability of the stamm reaction for rancidty

Summary The Korpaczy modification of the Stamm reaction for detecting rancidity in fats has been applied to a variety of fats and oils, including hog and beet fat, cottonseed oil, a number of other vegetable and seed oils, and a group of marine oils. This reaction has been shown to be generally inapplicable to vegetable, seed and marine oils but applicable to lard and beef fat.     

Synthese teilchlorierter epoxidierter Fettderivate und ihre Anwendung als Kunststoffadditive

Synthesis of Partially Chlorinated, Epoxidized Fat Derivatives and their Use as Plastics Additives Epoxidized oils and fatty acid esters can markedly increase the effectiveness of the primary stabilizer system in PVC. Epoxidized oils have no effect on the initial colouring, and expensive costabilizers have to be added in order to improve it. After being first partially chlorinated, unsaturated fats and fatty acid methyl esters were subsequently epoxidized. The samples were incorporated into PVC formulations and their stabilizing effect compared with that of commercially-available epoxidized fats. The long-term effect builds up as a function of the epoxy groups, and the initial colouring improves as a function of the Cl content (up to 7 wt. % Cl). The partially-chlorinated, epoxidized soybean oils with a Cl content of 4.5–6.5 wt. % impart a considerably better initial colour to the PVC samples than the commercially-available costabilizers on an epoxidized fat basis, while exhibiting a comparable long-time stability.     

Dietary lipids and arteriosclerosis

A great deal of attention has been given to the question of whether dietary fats in general and certain fats in particular play an important part in such arteriosclerotic complications as heart attacks and strokes. Milk fats have been widely accepted as desirable nutritional fats. Cow milk fat, or butter, contains a wide variety of fatty acid derivatives, including the important, medium chain acids. The structural configuration of butter triglycerides facilitates absorption of the palmitate present in butter. However, there have been objections to the use of butter and other forms of milk fat because of the preoccupation of many investigators with the unproven lipid theory of arteriosclerosis, and because serum cholesterol levels are relatively high after the intake of milk fat. Reevaluation of the lipid theory suggests that cholesterol can hardly be an atherogenic factor. Cholesterol occurs under conditions of tissue repair, and it may well be that the high serum levels in arteriosclerotic conditions are a consequence of such processes. The low serum levels occurring after the consumption of polyunsaturated vegetable oils are often associated with high tissue levels of cholesterol. Long term clinical studies and population surveys suggest that this century’s changes in mortality and morbidity are much less related to dietary factors (other than over-eating) than is claimed. New insights in the fields of immunology and microbiology may be vastly more important for an understanding of some etiological factors in arteriosclerosis.     

Manufacture of fatty alcohols based on natural fats and oils

The present worldwide capacity of fatty alcohols is ca. 1.0 million metric tons per year. About 60% of this capacity is based on petrochemical feedstocks, 40% on natural fats and oils. Three basic dominating commercial-scale processes are used to manufacture fatty alcohols: the Ziegler process and the Oxo synthesis starting from petrochemical feedstocks, and the high-pressure hydrogenation of natural fatty acids and esters. Basically, the high-pressure hydrogenation can be used with triglycerides, fatty acids or fatty acid esters as feedstock. The direct hydrogenation of fats and oils has not been developed to a commercial-scale process, mainly because it was not possible to prevent decomposition of the valuable byproduct glycerol. Conversion of fatty acids into fatty alcohols by catalytic hydrogenation without preesterification requires corrosion-resistant materials of construction and acid-resistant catalysts. Required reaction temperatures are higher, resulting in a higher hydrocarbon content. The majority of fatty alcohol plants based on natural fats and oils use methyl esters as feedstock. These can be made either by esterification of fatty acids or by-transesterification of triglycerides. For catalytic high-pressure hydrogenation of methyl esters to fatty alcohols, several process options have been developed. The bawic distinguishing feature is the catalyst application either in a fixed bed arrangement or suspended in the methyl ester feed.     

Development of mineral oil free offset printing ink using vegetable oil esters

Until the middle of this century, fats and oils are the major raw material source for paints, coating and lubricating applications. These markets are completely taken over by petroleum based stocks due to their abundance and versatility. However, recent public awareness to use environmentally acceptable products that minimize pollution, are compatible to human health and readily biodegradable created opportunities for vegetable oils for application in paints and printing inks. The formulation of vegetable oil methyl ester based 'green' offset printing ink that reduces the volatile organic compounds (VOC) has been discussed in the present study. Methyl esters of rapeseed, soybean, rice bran and palm oil have been prepared and their physical properties have been measured and compared with standard petroleum feed stock. Varnishes were prepared with these esters and their properties are also compared with that of the petroleum based products. Rheological properties of the inks are also evaluated and compared with standard printing ink using petroleum based solvent. In general performance of the ester-based printing inks are comparable with that of the mineral oil based product. On the basis of tack stability and gloss, ester based inks are much superior than the mineral oil based products. In conclusion, a new non-volatile diluent for printing ink has been developed. The diluent is made from common vegetable oils like rapeseed, soybean, rice bran and palm oil, a renewable source that is environmental friendly. Vegetable oil esters offer a cost effective solution for mineral oil based printing ink to meet VOCs regulations.     

Rapid FT-NIR Analysis of Edible Oils for Total SFA, MUFA, PUFA, and Trans FA with Comparison to GC

Declarations of the total content of trans fatty acids (FA) and saturated FA (SFA) are mandatory on food labels in the US and Canada. Gas chromatography (GC) has been the method of choice for the determination of FA composition. However, GC is time consuming and requires conversion of fats and oils to their FA methyl esters. In the present study, a recently published Fourier transform near-infrared (FT-NIR) spectroscopic procedure was applied to the rapid (<5 min) determination of total SFA, monounsaturated FA (MUFA), polyunsaturated FA (PUFA), and trans FA contents of 30 commercially available edible fats and oils. Good agreement was obtained between the GC and FT-NIR methods for the determination of total SFA, MUFA, and PUFA contents. Differences between the two methods were apparent for the determination of trans fat at trans fat levels <2 % of total fat. The analytical determinations of total SFA, MUFA, and PUFA contents for many of the oils examined differed from the respective values declared on the product labels. Our findings demonstrate that the FT-NIR procedure serves as a suitable alternative method for the rapid determination of total SFA, MUFA, PUFA and trans FA contents of neat vegetable oils.     

Fat in today’s food supply—Level of use and sources

Nutrient fat—food fats and oils, as well as fat from meat, milk, and other fat containing foods—in the U.S. food supply has increased ca. one-fourth over the past 60 years or so on a per person/day basis. Ca. two-fifths of the fat currently comes from fats and oils, including butter; over a third comes from meat (including fat pork cuts), poultry, and fish; and ca. one-eight comes from dairy products. This large increase in nutrient fat is due mainly to the use of more vegetable fats—margarine, shortening, and salad and cooking oils. The per capita amount provided by animal fats actually has decreased, because the large decreases in consumption of butter and lard are only partly offset by increases in fat associated with greater consumption of meats. Despite the decrease in consumption of animal fats, they continue to provide ca. one-fourth of the total calories. Although the proportion of calories from vegetable fats has increased, animal products still account for the largest share of the calories provided by fat. Shifts in sources of fat and the increased amount of fat have changed the fatty acid content of the food supply. One of five papers presented at the symposium, “Status of Fat in Food and Nutrition,” AOCS Fall Meeting, Chicago, September 1973. ARS, USDA.     

Acetin fats. I. Products made from mixed acetin fats

Summary The most striking effect of the introduction of the acetyl group into the glyceride molecule is the reduction in melting point. This effect permits the preparation of low melting fats and oils, or acetin fats, of a high degree of saturation and of a significantly increased oxidative keeping quality. Mixed acetin fats containing monoacetyl (monoacetins), diacetyl (diacetins), and normal triglycerides were made by random interesterification of normal fats or oils with triacetin, followed by removal of the residual triacetin. In general, mixed acetin fats may replace normal triglycerides in any edible fat use. Edible fat products including shortenings, margarines, or spreads, salad oils, and frying oils were made from acetin fats and oils. Suggested inedible use applications of the acetin fats and oils include plasticizers, tinning oils, and hydraulic oils.     

Fatty acid esters of glycidol in refined fats and oils

Discrepancies in the analysis of 3‐chloropropane‐1,2‐diol (3‐MCPD) esters can be explained by the hypothesis that in some refined oils significant amounts of fatty acid esters of glycidol (glycidyl esters) are present in addition to 3‐MCPD esters. Glycidyl esters were separated from triacylglycerols by gel permeation chromatography (GPC) and detected by gas chromatography‐mass spectrometry (GC‐MS). Six samples of palm oil and palm oil‐based fats were analyzed by GPC and GC‐MS. In chromatograms of all samples, significant peaks, retention time and mass spectra in conformity with self‐synthesized glycidyl palmitate and glycidyl oleate were detectable. Quantification of individual glycidyl esters was not possible because of a lack of pure standards. Concentration of ester‐bound glycidol in different samples of fats and oils was estimated using an indirect difference method. Glycidyl esters could be detected only in refined, but not in crude or native, fats and oils. The highest concentrations were detected in palm oil and palm oil‐based fats. In a palm oil sample, glycidyl ester concentration varied according to different deodorization parameters, temperature, and time, while 3‐MCPD ester concentration was relatively constant, indicating that mitigation of glycidyl esters possibly may be achieved by optimizing refining parameters.