A simple photometric method for microdetermination of fatty acids in lipids

A single step photometric micromethod for determination of fatty acids in lipids in benzene solution, using rhodamine 6G reagent, has been developed. The method eliminates the disadvantage of formation of a biphasic system and is applicable in the presence of glycerides, sterols, epoxy compounds, hydrocarbons and long chain hydroxy compounds such as long chain fatty alcohols. The long chain fatty acids from C₁₂ to C₂₂, both saturated and unsaturated, can be determined with reasonable accuracy in the concentration range of 0.08–0.25 μmole/ml. The method is simple, rapid, and requires relatively inexpensive chemicals.     

Background,importance and production volumes

The importance of the fatty acid industry today is reflected by the estimated 1978 production in the U.S. of 956 M lbs., exclusive of tall oil fatty acids. The 1978 U.S. production of various fatty acids as reported monthly and annually by the FAPC of SDA, is broken down into 9 saturated categories, and 5 unsaturated categories, as follows: (1) stearic and 127.2 M lbs. (13.3%); (2) hydrogenated animal and vegetable acids (2a) 97.3 M lbs. (10.2%), (2b) 158 M lbs. (16.5%), (2c) 32 M lbs. (3.4%); (3) high palmitic, 14.6 M lbs. (1.5%); (4) hydrogenated fish, 6.5 M lbs. (0.7%); (5) lauric acid types, 88.8 M lbs. (9.3%); (6) fractionated fatty acids, (6a) C₁₀ or lower, 18.5 M lbs. (1.9%), (6b) C₁₂ and C₁₄ 55% 17 M lbs. (1.9%); (7) oleic acid, 158.3 M lbs. (16.6%); (8) animal fatty acids other than oleic, 156.3 M lbs. (16.3%); (9) vegetable or marine fatty acids, 0.1 M lbs. (less than 1%); (10) unsaturated fatty acids, 57 M lbs. (6.0%); (11) unsaturated fatty acids I.V. over 130, 24.2 M lbs (2.5%). Reported 1977 fatty acid derivative production from fatty acids (not fats and oils) is 1,980 M lbs. The average price of fatty acids has increased from 23￠/lb.. to 60￠/lb. within the last 5 years.     

Substrate preferences for lipase-mediated acyl-exchange reactions with butteroil are concentration-dependent

Substrate preferences for pancreatic lipase-mediated acyl-exchange reactions with butteroil were concentration-dependent for the series of acyl donors and alcohol acceptors evaluated. For acidolysis reactions, the initial reaction rates and percent reaction yields after 18 h at 50 μmol acyl donor per gram substrate mixture were similar forn-fatty acids and their methyl and glycerol esters. At 400–500 μmol g⁻¹ (and greater), order of initial reaction rates and percent reaction yield was fatty acid glycerol esters > fatty acid methyl esters > fatty acids. At concentrations above 300–500 μmol g⁻¹, reaction inhibition was observed for fatty acid substrates, and inhibition took place at lower concentrations for the shorter-chainlength fatty acids of those evaluated (5–17 carbons). Inhibition was primarily attributed to acidification of the microaqueous environment of the lipase. Desorption of water by the fatty acid substrate may be a secondary mode of inhibition. The concentration dependence of initial reaction rates and percent reaction yield was similar for then-alcohol substrates evaluated (2–15 carbons) for alcoholysis reactions with butteroil. Optimum alcohol concentration was 375–500 μmol g⁻¹ (except for butanol, which was 1 mmol g⁻¹, above which reaction inhibition was observed. Inhibition was attributed to desorption of water from the enzyme by the alcohol substrate. Relative reactivity of classes of alcohols for this reaction system was primary alcohols > secondary alcohols > tertiary alcohols. Generally, alcoholysis reactions were faster than acidolysis reactions, and triacylglycerols were the best substrates for acidolysis reactions with butteroil at high levels (up to 2 mmol g⁻¹) of acyl donor substrate.     

Three Major Negative Factors for Prices of Plastic Raw Materials

<正> In 2010,China will continue to spur its domesticdemand and implement consumer incentivepolices on household appliances,automobilesand agricultural machineries,so thedemand for plastic raw materials will grow.For example,domestic consumption of polyethylene(PE),a major plastic raw material,will reach 16.37 million tons in 2010.Three major negative factors - low-cost resinsimported from the Middle East,the zerotariff of the China-ASEAN (the Associationof Southeast Asian Nations) free trade areaand China's capacity expansion - may inhibitthe increase of plastic raw material prices,but due to rising crude oil prices and the recoveryof the world economy,plastic rawmaterials prices will keep rising this year.     

Adsorptive bleaching and molecular distillation of menhaden oil

Some of the major barriers to wide acceptance of fish oils as sources of polyunsaturated triglycerides, fatty acids, and fatty acid derivatives have been the problems associated with color, odor, flavor, and other impurities. Adsorptive bleaching and molecular distillation were investigated as methods to obtain natural triglycerides from menhaden oil that do not have undesirable flavors and odors. Results of these studies have shown that certain activated clays will satisfactorily reduce the color of commercial menhaden oil but will not remove the odor and flavor. Molecular distillation was found to be more effective in improving the odor and flavor of the oil than adsorptive bleaching with activated clays but somewhat less effective in reducing the color. When used jointly with bleaching, molecular distillation yields menhaden oil of high quality, suitable for use both in animal and human nutrition and in medical research. Spectral data in the 400–700 mμ range were used to evaluate the success of the refining process.     

Bleaching off-colored cottonseed oils with activated alumina: A preliminary cost study

The majority of off-colored cottonseed oils can be bleached to a prime color with 4% by weight or less of activated alumina in a single operation. Increasing the amount of alumina beyond 4% makes it possible to bleach the most difficult-to-bleach off-colored cottonseed oils. Although additional research is required to establish the process and optimize conditions, results of a preliminary cost study indicate that this method should be competitive on a large scale with rerefining followed by conventional earth bleaching. A flow sheet is given. Investment and operating costs are reported for bleaching for six months annually in plants having daily capacities of 100,000, 500,000, and 1,000,000 lb of cottonseed oil, prime and/or off-colored, in batches of 6,000, 30,000, and 60,000 lb, respectively. It is estimated that alumina bleaching of off-colored oil, with solvent extraction of oil from spent alumina, would cost as little as 0.4￠/lb in the largest plant, 0.5￠/lb in the medium plant, and 1.2￠/lb in the small plant. These costs are calculated on the basis of the use of 4% alumina by weight of oil for off-colored oil during one-fourth of the season, in combination with 1%, 2%, or 4% of alumina for prime oil during three-fourths of the season. Costs could be lowered by reducing oil losses and losses of alumina in regeneration, increasing filtration rates, and lowering alumina price as a result of additional research on its preparation. Lowered cost would make the method more attractive forprime oils as well. Presented at the AOCS meeting in New Orleans, La., 1962. A laboratory of the So. Utiliz. Res. & Dev. Div., ARS, U.S.D.A.     

Rapid colorimetric determination of free fatty acids

In 1964, a method was described for the determination of free fatty acids (FFAs) in vegetable oil. This paper describes an expansion of that work, improving the sensitivity and reproducibility of the method, as well as examination of solubilities of the copper soaps as a function of chain length and unsaturation. Involvement of the micellar structure was reviewed. Finally, a procedure is described that permits very rapid determination of FFA at the 2.0–14.0 μmol (0.5–4.0 mg oleic acid) level, and the results with several oils are given. Particular attention was given to evaluation of solvent systems which would extract the copper complexes. Presented in part at the AOCS Meeting in San Francisco, April 1969. Technical Paper No. 4036, Oregon Agricultural Experiment Station.     

Fatty acid polymorph identification by infrared

IR spectra in the 7.5–25.0 μm region are shown to be unique for polymorphic modifications of long chain saturated fatty acids of even carbon number and also for the individual fatty acids. IR spectra are presented for the A-, B-, C- and E-forms of stearic acid and for the C-form of myristic, palmitic, arachidic and behenic acid and the differences discussed. X-ray determined crystal long spacings for the A-, B-, C- and E-forms of a series of homologous even carbon-numbered acids are presented and compared with literature values. The formation of the different polymorphic forms are found to be temperature-concentration related and affected little by polarity of the solvent. Wideline nuclear magnetic resonance second moment values are given for the polymorphic forms of stearic acid. Presented in part at the AOCS Meeting, Houston, May 1971. S. Market. Nutr. Res. Div., ARS, USDA.     

Fatty acid and tocopherol contents and oxidative stability of walnut oils

Walnuts (Juglans regia L.) were collected during the 1997 harvest from 13 different cultivars of trees grown in a replicated trial in an experimental orchard at Lincoln University. Two U.S. commercial cultivars (Tehama and Vina), three European commercial cultivars (Esterhazy, G139, G120), and eight New Zealand selections (Rex, Dublin’s Glory, Meyric, Stanley, Mckinster, 150, 151, 153) were evaluated. Total lipids were analyzed for fatty acids by capillary gas chromatography, tocopherols by high-performance liquid chromatography, and oxidation stability by Rancimat. The total oil content of the nuts ranged from 64.2 to 68.9% while the stability of the oil ranged from 3.9 to 7.8 h. The oleic acid content of the oils ranged from 12.7 to 20.4% of the total fatty acids, while 18:2 content ranged from 57.0 to 62.5% and the 18:3 contents ranged from 10.7 to 16.2%. Reduced stability of the oil as measured by the Rancimat method appears to be correlated to higher levels of 18:2 in the extracted oil. The total tocopherol contents of these nuts ranged from 268.5 to 436.0 μg/g oil. γ-Tocopherol dominated the profile while α-tocopherol was only 6% of the total content. Peroxide values of the fresh oil were measured spectrophotometrically to give an indication of the overall stability. The levels of total tocopherols when combined with the level of unsaturation in the oil in a multiple regression analysis had a significant relationship (R ²=45.2%, P<0.001) with the peroxide value in the oil. Presented as a poster at the 89th AOCS Annual Meeting, Chicago, Illinois, May 10–13, 1998.     

Wetting of fat crystals by triglyceride oil and water. 2. adhesion to the oil/water interface

Fat crystals influence the stability of food emulsions, such as margarine, butter, or cream, if adsorbed to the oil/water interface. During the adsorption process, a new fat crystal/water interface is created, while the oil/water interface is lost. The driving force for adsorption is therefore the difference between the interactions between fat crystal/water and oil/water. In this work, we have estimated this interaction difference and compared it to the displacement energy for fat crystals from the oil/water interface to the oil. Our calculations have shown that fat crystal adsorption to the oil/water interface (expressed by contact angle ϑ) is determined by polar energy, excess of fat crystal/water over oil/water (I _sw -I _ow ). The interfacial tension constitutes the resistance force for crystal adsorption to the interface. Polar interaction energy for fat crystal/water is stronger than the polar interaction energy for oil/water in all cases examined (I _sw -I _ow >0). The difference corresponds to about 10⁴–10⁶ hydrogen bonds for a hypothetical fat crystal with a diameter of 1 μm. The displacement energy for fat crystals to oil is lower than the polar energy excess in most cases examined. Thus, an additional interaction between fat crystals and oil makes it easy to displace the crystals to the oil. There is also a relationship between the adhesion tension (-γ _ow • cos ϑ) for the crystals at the oil/water interface and the interfacial tension γ _ow . A straight line of slope -1 is achieved for systems with low interfacial tensions (γ _ow ) and low polar energy excess (I _sw -I _ow ).     

Nitrogenous Fertilizer Manufacturers Promise to Increase Production

In 2005 the total domestic urea output isexpected to be 3 million tons more thanlast year,and the export amount will bereduced by 3 million tons.In the recentlyended mobilization meeting for increas-ing fertilizer production held by China Ni-trogenous Fertilizer IndustryAssociation,the representatives of large-and mid-scale enterprises advocated,inrespond to the government's call,to be     

Enzymatic glycerolysis of soybean oil

Enzymatic glycerolysis of soybean oil was studied. Of the nine lipases that were tested in the initial screening, Pseudomonas sp. resulted in the highest yield of monoglycerides. Lipase from Pseudomonas sp. was further studied for the influence of temperature, thermal stability, enzyme/oil ratio, and glycerol/oil ratio. A full factorial optimization approach was performed. The following conditions were tested over the specified ranges: temperature (30–70°C), thermal stability (30–70°C), enzyme/oil ratio (0.05–0.2 g enzyme/10 g oil), glycerol/oil ratio (1:1–3:1 glycerol/oil molar ratio) and 1 h reaction time. The stability of the enzyme at the reaction temperature was also incorporated as a separate variable. At temperatures above 40°C enzyme denaturation offset the higher activity. The optimal conditions were selected to be the basis for a continuous process: 40°C, a glycerol/oil molar ratio of 2:1, and an enzyme/oil ratio of 0.1 g enzyme/10 g oil. A definition for glycerolysis activity was adopted. The glycerolysis activity (1 GU) was defined as the amount of enzyme necessary to consume 1 μmol of substrate (glycerol and oil) per minute. This research is intended to explore the reaction parameters that are important in a continuous enzymatic glycerolysis process.     

Synthetic fatty acids in Eastern Europe

For over a century various investigators have studied the air oxidation of paraffinic hydrocarbons to produce synthetic fatty acids. Today in the socialistic countries there are six to eight plants manufacturing these acids to replace in soaps tallow fatty acids which are needed as a source of food. The principal technological advances in air oxidation, prior to World War II, were made by Germany while more recently Russia and its satellite countries have made the major contributions. Although the oxidation involves a multitude of chemical reactions taking place consecutively and simultaneously, it has been fairly well established that the alkylhydroperoxide precursors are converted to alcohols and then further oxidized to carboxylic acids. The cost of manufacturing synthetic fatty acids in Eastern Europe ranges between 8–12￠ per pound depending upon the raw material, processing costs and by-products.     

Lipid composition and oxidative stability of oils in hazelnuts (Corylus avellana L.) grown in New Zealand

Hazelnut (Corylus avellana L.) samples were collected from six different cultivars of trees grown in an experimental orchard at Lincoln University. Three U.S. commercial cultivars (Butler, Ennis, and Barcelona), two European commerical cultivars (Tonda di Giffoni and Campanica), and one New Zealand selection (Whiteheart) were evaluated. The total oil, stability to oxidation of the oil, and fatty acid, tocopherol, and sterol composition were determined on samples of freshly extracted hazelnut oil. The total oil content of the seeds ranged from 54.6 to 63.2% while the stability of the oil, as measured by the Rancimat test ranged from 15.6 to 25.3 h. The content of the monounsaturated oleic acid in the oils ranged from 73.8 to 80.1% of the total fatty acids, while the tocopherol content ranged from 225.8 to 552.0 mg/g freshly extracted oil. The major desmethylsterols were sitosterol, ranging from 1416 to 1693 μg/g, campesterol, ranging from 78 to 114 μg/g, and Δ5-avenasterol, ranging from 110 to 170 μg/g. The oil extracted from the cultivar Whiteheart was more stable (measured by Rancimat) than the oil from all other cultivars grown at the same location and under the same conditions. Whiteheart contained higher levels of total and γ-tocopherol when compared to the other cultivars. The higher levels of tocopherol in Whiteheart help to explain the greater stability of the oil during the oxidative stress test. These results suggest that nuts from the cultivar Whiteheart could be stored longer than the other nuts tested. Presented as a poster at the 87th AOCS Annual Meeting, Indianapolis, Indiana, April 28–May 1, 1996.     

A rapid method for the estimation oftrans unsaturation in hydrogenated oils and fats

Glycerides and methyl esters of fatty acids containingtrans unsaturation both show peaks at 10,38 μ. The absorptivities of the glycerides (a_10.38 μ) have a straight line relationship with the concentration of thetrans unsaturation, calculated as methyl elaidate. This relationship has been utilized as a quick method for estimating thetrans unsaturation in hydrogenated fats such as Vanaspati. The infrared spectrum of a given hydrogenated fat is taken in the region of 9–11 μ, the absorptivity at thetrans-peak is calculated, and the corresponding methyl elaidate content is read from a graph.     

Reaction of cysteine and methionine with malonaldehyde

Malonaldehyde (M), a product of polyunsaturated fatty acid oxidation, reacted with the sulfhydryl as well as with the amino groups of cysteine (cys). The cys-M product had an absorption maximum at 310 mμ, and the extinction coefficient at pH 7.0 was 2.3 × 10⁴. Elementary analysis of the cys-M product agreed with a structure in which 2 moles of cysteine had reacted with 3 moles of malonaldehyde. The molecular weight of cys-M preparations increased on storage and the UV absorption changed from 310 to 315–320 mμ, with a consequent shift to longer wavelength in the visible. Methionine (meth) reacted with malonaldehyde under the same reaction conditions only at the α-amino group, similar to glycine (gly). The apparent pK_a of the carboxyl group of gly-M increased to 3.36 and that of meth-M to 3.19, representing an increase of about one pK_a unit over the natural amino acids. For gly-M and meth-M the respective absorption maxima were 272 and 282 mμ. The spectral shifts from 267 to 315 mμ of the amino acid-M products with respect to β-oxyacrolein were explained in terms of increasing substitution at the β-carbon of the α,β-unsaturated carbonyl system. When the α-amino-malonaldehyde condensation products of methionine and glycine reacted with semicarbazide the original amino acids and disemicarbazone of malonaldehyde were formed.     

A rapid method for the determination oftrans unsaturation in fats and derivatives

Thetrans unsaturation present in samples of unsaturated fats and derivatives may be determined from measurement of the infrared absorbance at two wavelengths, one due totrans configuration of a double bond and the other due to the ester or acid group. The ratio of the two absorbance values has a linear relationship with thetrans unsaturation content. Thus, a drop of sample is diluted with CS₂ and the infrared absorbance measured at 10.36 μ and at 8.5–8.6 μ if esters and 10.7 μ if acids. To calculate the per cent isolatedtrans double bonds in the sample, the ratio of the two absorbance values is substituted into the linear equation which was developed from known samples. The method is rapid since the sample need not be weighed nor made up to a known volume and thus may be applied to samples such as those collected from a gas chromatograph or after thin layer chromatography. Presented at the AOCS Meeting, New York, October 1968.     

High performance size exclusion chromatography of fatty acids,mono-, di- and triglyceride mixtures

A high performance size exclusion chromatographic (HPSEC) method is described for the separation and quantitation of fatty acids, mono-, di- and triglyceride mixtures. The various lipid components were separated on two columns packed with 5 μm styrene/divinylbenzene copolymer and connected in series. Toluene was employed as eluant, and components were monitored by refractometry. A formula derived for calculation of total weighted correction factors (WCF) for the various lipid classes based on known values of correction factors of simple lipid components and the fatty acid composition of the sample allowed quantitation of lipid mixtures containing a variety of different molecules. The precision of the experiments is such that the relative standard deviation for each lipid component was 1–5%, and a component could be detected at 0.05% level.     

Construction Material Industry 2009 Economic Operation Report

<正> China's construction material exports haddropped since August 2008 due to the global financial crisis. There after the growth of the domestic construction material industry slowed while production for some products declined. Thanks to the government's macro-economic measures of "ensuring growth and expanding domestic demand", the industry reversed the decline in growth in the second half of 2009. Major construction material makers in China, which include companies with annual sales of at least RMB5 million and all state-owned companies, reported combined sales revenue of RMB2.1 trillion in 2009, up 22.6% from ayear earlier. They posted combined profit of RMB150 billion, up 22.5% from a year earlier. The gross profit margin of the domestic construction material sector averaged 15% in 2009. Although prices of raw materials, fuels, and     

The bioassay of aflatoxins and related substances with Bacillus megaterium spores and chick embryos

The “paper disc plate” method of antibiotic assay usingBacillus megaterium spores was tested for the assay of aflatoxins and related compounds. Significant inhibitions were obtained in the range of 1–4 μg/disc for aflatoxin B₁ and 4–8 μg/disc for aflatoxin G₁. Dicumarol was the most active of the compounds tested and inhibited at 0.1–1.0 μg/disc. Compounds were also tested using nine-day-old chick embryos. It was found that embryos incubated in egg cartons were much more sensitive to toxins than eggs incubated on cotton padding or in a commercial egg incubator. The LD₁₀₀ of aflatoxin B₁ to carton-incubated embryos was 0.01 μg, while to embryos from the commercial incubator the LD₁₀₀ was >5.0 μg. The results of the two bioassay procedures did not correlate completely with each other. Presented at the AOCS-AACC joint meeting in Washington, D.C., 1968.