棕榈油基可生物降解润滑剂的制备

为制备可生物降解的润滑剂,该文以棕榈油为原料制备三羟甲基丙烷三酯,用气相内标法测定三酯的生成率。通过响应面优化后,三酯的生成率最高为88.75%,经分子蒸馏后,三酯的纯度为98.6%,结构经红外光谱和质谱表征。以分子蒸馏后的产品为基础油,PB-1300（聚异丁烯）、T803B（聚α-烯烃）、BHT（2,6-二叔丁基对甲酚）和司苯-80（山梨糖醇单甘油酯）为添加剂,复配得到成品润滑剂。该润滑剂除低温性能与抗氧化能力较差外,具有很好的黏温性能和安全稳定性、无毒且易生物降解。     

菜籽油皂脚中游离脂肪酸分子蒸馏分离模拟

该文利用分子蒸馏模型模拟分离皂脚中脂肪酸,进而为后续高效率制备生物柴油奠定基础.根据建立的分子蒸馏模型和物化参数的估算,对菜籽油皂脚中游离脂肪酸的分离进行模拟,并与实际试验数据进行了比较.研究结果表明:该模型在模拟分离菜籽油皂脚中游离脂肪酸时的结果与试验结果曲线趋势相近.随着蒸馏温度的增加,蒸馏量增大,蒸馏量模拟值与实验值的相对误差不超过16%.随着蒸馏温度的增加,重组分中游离脂肪酸含量不断降低,试验结果的脂肪酸浓度都大于模拟值,而相对误差随温度升高不断降低,蒸馏温度为453 K时较蒸馏温度为423 K时,相对误差降低近50%.     

Analysis of free fatty acids in whey products by solid-phase microextraction

To evaluate the impact of Cheddar cheese starter cultures on the level of free fatty acids in liquid whey, a solid-phase microextraction (SPME) technique was utilized. The determination of response factors relative to an internal standard and the verification of linearity over a wide concentration range allowed for the quantitation of free fatty acids in experimentally produced liquid whey and in a wide range of dry whey ingredients. Results indicated that whey produced with a Lactococcus lactis subsp. lactis starter culture contained the highest level of total free fatty acids with significantly higher levels of lauric, myristic, and palmitic acids. Significant declines in oleic, linoleic, and palmitic acid occurred during storage. Commercial whey ingredients demonstrated a linear increase in free fatty acids with increasing percent protein, except for whey protein isolate, which had the lowest concentration. The use of SPME for the rapid analysis of free fatty acids in whey products should allow for further research to determine the importance of these compounds on the quality and stability of whey products.     

Determination of ethylene oxide in ethoxylated surfactants and demulsifiers by headspace gas chromatography

A headspace gas chromatographic method for the determination of traces of ethylene oxide in ethoxylated surfactants and demulsifiers was developed. Samples are analyzed directly by the technique to a 1.0 ppm (w/w) quantitation limit. The procedure also performs well for propylene oxide, acetaldehyde, and 1,4-dioxane. It is simple, sensitive, and linear. The percent relative standard deviations for 0.5 and 30 ppm ethylene oxide in the surfactant were 2.8 and 8.3%, respectively.     

Acidolysis of tristearin with selected long-chain fatty acids

Five lipases, namely, Candida antarctica (Novozyme-435), Mucor miehei (Lipozyme-IM), Pseudomonas sp. (PS-30), Aspergillus niger (AP-12), and Candida rugosa (AY-30), were screened for their effect on catalyzing the acidolysis of tristearin with selected long-chain fatty acids. Among the lipases tested C. antarctica lipase catalyzed the highest incorporation of oleic acid (OA, 58.2%), gamma-linolenic acid (GLA, 55.9%), eicosapentaenoic acid (EPA, 81.6%), and docosahexaenoic acid (DHA, 47.7%) into tristearin. In comparison with other lipases examined, C. rugosa lipase catalyzed the highest incorporation of linoleic acid (LA, 75.8%), alpha-linolenic acid (ALA, 74.8%), and conjugated linoleic acid (CLA, 53.5%) into tristearin. Thus, these two lipases might be considered promising biocatalysts for acidolysis of tristearin with selected long-chain fatty acids. EPA was better incorporated into tristearin than DHA using the fifth enzymes. LA incorporation was better than CLA. ALA was more reactive than GLA during acidolysis, except for the reaction catalyzed by Pseudomonas sp., possibly due to structural differences (location and geometry of double bonds) between the two fatty acids. In another set of experiments, a combination of equimolar quantities of unsaturated C18 fatty acids (OA + LA + CLA + GLA + ALA) was used for acidolysis of tristearin to C18 fatty acids at ratios of 1:1, 1:2, and 1:3. All lipases tested catalyzed incorporation of OA and LA into tristearin except for M. miehei, which incorportaed only OA. C. rugosa lipase better catalyzed incorporation of OA and LA into tristearin than other lipases tested, whereas the lowest incorporation was obtained using Pseudomonas sp. As the mole ratio of substrates increased from 1 to 3, incorporation of OA and LA increased except for the reaction catalyzed by A. niger and C. rugosa. All lipases tested failed to allow GLA or CLA to participate in the acidolysis reaction, and ALA was only slightly incoporated into tristearin when M. miehei was used.     

Influence of heating time and metal ions on the amount of free fatty acids and formation rates of selected carbonyl compounds during the thermal oxidation of canola oil

Canola oil was heated continuously for 8 h at a typical frying temperature (180 °C) in the presence of various concentrations of the metal ions Fe(III), Cu(II), and Al(III) (9.2, 27.5, and 46.0 μg L(-1) of oil) to evaluate changes occurring in the amount of free fatty acids, expressed as acidity index, and in the formation rates of aldehydes. The aldehydes were collected and derivatized in silica cartridges functionalized with C18 and impregnated with an acid solution of 2,4-dinitrophenylhydrazine, after which they were eluted with acetonitrile and analyzed by LC-DAD-MS. Among the substances emitted, the following were identified and quantified: formaldehyde, acetaldehyde, acrolein, propanal, butanal, hexanal, (E)-2-heptenal, and octanal. During heating of the oil, the compounds presenting the highest mean formation rates were acrolein, hexanal, and acetaldehyde. In the study of the metal ions, the addition of ions to the samples generally led to a corresponding increase in the formation rates of the eight substances. The compounds showing the highest relative increases in formation rates were formaldehyde, acetaldehyde, propanal, and heptenal. In terms of catalytic effect, copper proved to be the most efficient in promoting increased formation rates, followed by iron and aluminum.     

Determination of furan fatty acids in extra virgin olive oil

The presence of 4 different furan fatty acids (F-acids) was detected in 18 samples of transmethylated monovarietal extra virgin olive oil: methyl 10,13-epoxy-11,12-dimethyloctadeca-10,12-dienoate [diMeF(9,5)], methyl 12,15-epoxy-13,14-dimethyleicosa-12,14-dienoate [diMeF(11,5)] and both olefinic derivatives of diMeF(11,5) with one unsaturation on the side chains conjugated with the furan ring. Transmethylated oils were analyzed by normal phase high-performance liquid chromatography coupled on-line with capillary gas chromatography. After the gas chromatographic separation step, a more selective detection of F-acids was achieved by using a photoionization detector mounted in series with a flame ionization detector. The concentration of F-acids ranged between 50 ppb (detection limit of the method) and 2.1 ppm in the oil. The olefinic derivatives of diMeF(11,5) acids detected were not artifacts created during the sample preparation or during the chromatographic analysis.     

Modified method for the analysis of free fatty acids in fish

The objective of this study was the development of a method for the quantification of free fatty acids (FFA) using less aggressive reactants against the handler and the environment than those used in the classic method of Lowry and Tinsley. The modified procedure is a variation of the Lowry and Tinsley method employing cyclohexane in place of benzene. The use of benzene is prohibited in certain work processes and laboratories, and the competent authority in each country is actively promoting research into harmless or less harmful products that could replace benzene. A comparison with the traditional AOCS titration method for oil analysis was performed. FFA content in mackerel frozen at -10 degrees C was measured according to the three methods over a 12 month period. The results showed similar values, and good correlations were obtained.     

Rapid determination of free fatty acids in poultry feed lipid extracts by SB-ATR FTIR spectroscopy

A simple, rapid, and reproducible method has been developed for the quantitative determination of free fatty acid (FFA) content in lipids extracted from poultry feeds by Fourier transform infrared (FTIR) spectroscopy with the use of a single-bounce attenuated total reflectance (SB-ATR) accessory. An FTIR calibration curve was prepared by gravimetrically adding oleic acid (15-37%) to pure refined, bleached, and deodorized (RBD) canola oil and measuring the area of the COOH absorption band at 1710 cm-1. The oil from each of 12 poultry feed formulations was extracted using conventional Soxhlet extraction, and after evaporation of the solvent, the FFA content was determined by the conventional AOCS titrimetric procedure and by the SB-ATR/FTIR method. The SB-ATR/FTIR FFA predictions were related to those determined by the AOCS titrimetric method by linear regression, producing an R value of 0.999 and a SD of +/-0.28% FFA. Time-course spectra collected as lipids extracted into hexane indicated that a 15 min extraction was adequate to obtain a representative sample for FFA determination, with further extraction resulting in little, if any, change in the proportion of FFA in the lipid extract. Only a small volume of the hexane extract ( approximately 20 mL) yielded sufficient material for the SB-ATR/FTIR analysis. Thus, by shortening the extraction time and taking a small sample so as to reduce solvent removal time, the SB-ATR/FTIR procedure provides a very simple and rapid means of determining the FFA content of poultry feed lipids.     

Liquid chromatographic method for quantitative determination of free fatty acids in butter

A liquid chromatographic method has been developed for the determination of free fatty acids in butter. The fatty acids are converted to the p-bromophenacyl esters, via a crown ether-catalyzed reaction, without separation from the other butter components. The esters are separated on a C18-bonded silica column by using an acetonitrile-water solvent gradient and quantitated using the ester of heptadecanoic acid as internal standard. C16 and C18:1 co-elute in the acetonitrile-water system but are separated using an isocratic methanol-acetonitrile-water system. Limits of detection range from 7 ng for butyric acid to 45 ng for linoleic acid. The average coefficient of variation (n = 10) for 10 free fatty acids from a butter was 5.83%.     

Anaerobic digestion of free volatile fatty acids in soils below waste tips

Leachate from a waste tip in the acidification stage contains a lot of volatile fatty acids. Soil column experiments showed that the removal of these acids in soil by CH₄-fermentation can be quite effective, especially in soils with a high buffering capacity. In sandy loam soil columns, where the retention time was only 17 days, the fatty acids were removed completely, even at a high concentration level of 6500 mg l^?1 acetic acid equivalents. In sandy soils with a low buffering capacity the CH₄-fermentation was already limited at rather low acid concentrations. The lag in the start of CH₄-fermentation became longer at higher acid concentrations. At a level of 25 000 mg l^?1 acetic acid equivalents CH4 -fermentation did not start within the test period of 10 months. The lowering of pH was probably the main reason for this phenomenon.     

Analysis of monoglycerides, diglycerides, sterols, and free fatty acids in coconut (Cocos nucifera L.) oil by 31P NMR spectroscopy

Phosphorus-31 nuclear magnetic resonance spectroscopy ( (31)P NMR) was used to differentiate virgin coconut oil (VCO) from refined, bleached, deodorized coconut oil (RCO). Monoglycerides (MGs), diglycerides (DGs), sterols, and free fatty acids (FFAs) in VCO and RCO were converted into dioxaphospholane derivatives and analyzed by (31)P NMR. On the average, 1-MG was found to be higher in VCO (0.027%) than RCO (0.019%). 2-MG was not detected in any of the samples down to a detection limit of 0.014%. On the average, total DGs were lower in VCO (1.55%) than RCO (4.10%). When plotted in terms of the ratio [1,2-DG/total DGs] versus total DGs, VCO and RCO samples grouped separately. Total sterols were higher in VCO (0.096%) compared with RCO (0.032%), and the FFA content was 8 times higher in VCO than RCO (0.127% vs 0.015%). FFA determination by (31)P NMR and titration gave comparable results. Principal components analysis shows that the 1,2-DG, 1,3-DG, and FFAs are the most important parameters for differentiating VCO from RCO.     

Nutritional characteristics of sago palm and oil palm in tropical peat soil

To make clear the nutritional characteristics of sago palm (Metroxylon sagu Rottb.) and oil palm (Elaeis guineensin Jacq.) grown in tropical peat soil, minerals concentration, organic compounds concentration, and photo‐synthetic rate were estimated, and the obtained results were as follows. Since, the nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and sodium (Na) concentration in mature leaves and trunk were higher in the oil palm than in the sago palm, but potassium (K) concentration was higher in the sago palm than in the oil palm, the minerals (especially N, P, Ca, and Mg) requirement for the oil palm were higher than in the sago palm. This indicates that the sago palm will adapt better than the oil palm to soils with poor nutrients. The manganese (Mn) and zinc (Zn) concentration in leaves of the sago palm and Ca and aluminum (Al) concentration in leaves of the oil palm increased with the increase of aging, indicating that those elements are eliminated from plants through leaf senescence. In the sago palm, the N and P distribution ratio to leaves remained almost constant during growth, indicating that N and P were predominantly distributed to leaves for maintaining leaf function. The photosynthetic rate [μmole carbon dioxide (CO₂) m² LA sec^‐1] at light saturation was lower in the sago palm (5.8) and oil palm (10.0) than in wheat (25.4). As leaf longevity of sago and oil palms was longer (about 12 times) than that of wheat (Triticum aevstium L.), and the minerals concentration and photosynthetic rate remained constant for a long duration of growth, the cumulative carbon (C) accumulation per unit dry weight (photosynthetic rate x leaf longevity) in the individual leaf is assumed to be equal or greater than that of wheat. The photosynthetic ability of sago and oil palms leaves is very important for understanding why sago and oil palms have high productivity in spite of a low nutrient environment.     

精炼工艺对亚麻籽油中反式酸含量的影响

本课题以含55%亚麻酸的压榨亚麻籽油为原料,研究亚麻籽油在精炼过程中油脂品质和反式酸含量的变化规律。结果表明,化学精炼和物理精炼工艺都能将亚麻籽毛油酸价由3.8mgKOH/g脱到0.3mgKOH/g以下;化学精炼过程亚麻籽油中反式酸含量变化由0.2%上升到0.4%;物理精炼过程亚麻油中反式酸含量变化比较明显,脱色后亚麻油反式酸含量为0.27%;在温度200℃,绝对压力10-50pa条件下亚麻油精炼脱酸,4h时亚麻油反式酸含量为0.91%,8h时反式酸含量为1.73%。另外研究表明,化学精炼过程亚麻油的过氧化值变化不大,经精炼后成品油过氧化值为4.1mmol/kg;物理脱酸过程中亚麻油的过氧化值缓慢增加,在200℃脱酸6h时,过氧化值为6mmol/kg以下。     

Hypolipidemic effect of oils with balanced amounts of fatty acids obtained by blending and interesterification of coconut oil with rice bran oil or sesame oil

Blended oils comprising coconut oil (CNO) and rice bran oil (RBO) or sesame oil (SESO) with saturated fatty acid/monounsaturated fatty acid/polyunsaturated fatty acid at a ratio of 1:1:1 and polyunsaturated/saturated ratio of 0.8-1 enriched with nutraceuticals were prepared. Blended oils (B) were subjected to interesterification reaction using sn-1,3 specific Lipase from Rhizomucor miehei. Fatty acid composition and nutraceutical contents of the blended oil were not affected by interesterification reaction. Male Wistar rats were fed with AIN-76 diet containing 10% fat from CNO, RBO, SESO, CNO+RBO blend (B), CNO+SESO(B), CNO+RBO interesterified (I), or CNO+SESO(I) for 60 days. Serum total cholesterol (TC), low-density lipoprotein cholesterol, and triacylglycerols (TAGs) were reduced by 23.8, 32.4, and 13.9%, respectively, in rats fed CNO+RBO(B) and by 20.5, 34.1, and 12.9%, respectively, in rats fed CNO+SESO(B) compared to rats given CNO. Rats fed interesterified oils showed a decrease in serum TC, low-density lipoprotein cholesterol (LDL-C), and TAGs in CNO+RBO(I) by 35, 49.1, and 23.2 and by 33.3, 47, and 19.8% in CNO+SESO(I), respectively, compared to rats given CNO. Compared to rats fed CNO+RBO blended oils, rats on CNO+RBO interesterified oil showed a further decrease of 14.6, 24.7, and 10% in TC, LDL-C, and TAG. Rats fed CNO+SESO interesterified oils showed a decrease in serum TC, LDL-C, and TAG by 16.2, 19.6, and 7.8%, respectively, compared to rats given blended oils of CNO+SESO (B). Liver lipid analysis also showed significant change in the TC and TAG concentration in rats fed blended and interesterified oils of CNO+RBO and CNO+SESO compared to the rats given CNO. The present study suggests that feeding fats containing blended oils with balanced fatty acids lowers serum and liver lipids. Interesterified oils prepared using Lipase have a further lowering effect on serum and liver lipids even though the fatty acid composition of blended and interesterified oils remained same. These studies indicated that the atherogenic potentials of a saturated fatty acid containing CNO can be significantly decreased by blending with an oil rich in unsaturated lipids in appropriate amounts and interesterification of blended oil.     

Simple and sensitive analysis of long-chain free fatty acids in milk by fluorogenic derivatization and high-performance liquid chromatography.

A highly sensitive high-performance liquid chromatography (HPLC) method is described for the simultaneous determination of some important saturated and unsaturated fatty acids in milk, including lauric (dodecanoic), myristic (tetradecanoic), palmitic (hexadecanoic), stearic (octadecanoic), palmitoleic (hexadecenoic), oleic (octadecenoic), and linoleic acids (octadecadienoic acids). The fatty acids were fluorogenically derivatized with 2-(2-naphthoxy)ethyl 2-(piperidino)ethanesulfonate (NOEPES) as their naphthoxyethyl derivatives. The resulting derivatives were separated by isocratic HPLC and monitored with a fluorometric detector (lambdaex = 235 nm, lambdaem = 350 nm). The fatty acids in milk were extracted with toluene, and the extract with the fatty acids was directly derivatized with NOEPES without solvent replacement. Determination of long-chain free fatty acids in milk is feasible by a standard addition method. A small amount of milk product, 10 microL, is sufficient for the analysis.     

Quantitative determination of short-chain free fatty acids in milk using solid-phase microextraction and gas chromatography

The objective was to establish a rapid, precise, and accurate methodology for the quantification of short-chain free fatty acids (FFA) (C(4)-C(12)) in milk by solid-phase microextraction and gas chromatography. Sampling conditions such as fiber type, pH, salt addition, temperature, volume, and time were investigated. FFA extraction consisted of placing 40 mL of milk containing 28% NaCl at pH 1.5 in a sealed vial and equilibrating for 30 min at 70 degrees C. A polyacrylate fiber was exposed to the sample headspace for 60 min and desorbed for 5 min into the gas chromatograph. Calibration curves for FFA followed linear relationships with highly significant (p < 0.001) correlation coefficients (R(2) = 0.99). Coefficients of variation of less than 7.7% for FFA concentrations indicated that the technique was reproducible. The limits of quantification for C(4)-C(10) were in the low parts per million level, which were below the concentration range found in fresh pasteurized milk (0.48-2.52 ppm) or rancid milk (4.73-32.31 ppm).     

A three component interaction among starch,protein, and free fatty acids revealed by pasting profiles

A three way interaction among starch, protein, and lipid that affects the Rapid Viscoanalyzer (RVA) paste viscosity profile was revealed using a model system composed of isolated sorghum starch, whey protein isolate, and free fatty acids (FFAs) (20:2:1, w/w/w). A prominent cooling stage viscosity peak in the RVA profile was produced when all three components were present in the system, while there was no viscosity peak when either protein or FFA alone was combined with starch. The magnitude of the cooling stage viscosity peak differed with addition of palmitic, oleic, or linoleic acids to starch and protein. Amylose was the major functional molecule of the starch component. Addition of both protein and FFA to starch substantially reduced starch solubility after gelatinization, while solubility was less affected by single addition of FFA and was not affected by protein. Nonspecificity of this interaction phenomenon was demonstrated by similar results using maize starch and other soluble proteins.     

Regioisomerism of triacylglycerols in lard, tallow, yolk, chicken skin, palm oil, palm olein, palm stearin, and a transesterified blend of palm stearin and coconut oil analyzed by tandem mass spectrometry.

Triacylglycerols (TAG) of lard, tallow, egg yolk, chicken skin, palm oil, palm olein, palm stearin, and a transesterified blend of palm stearin and coconut oil (82:18) were investigated by chemical ionization and collision-induced dissociation tandem mass spectrometry. Accurate molecular level information of the regioisomeric structures of individual TAGs was achieved. When existing in a TAG molecule of lard, palmitic acid occupied 90-100% of the sn-2 position. Within the major fatty acid combinations in tallow TAGs, the secondary position sn-2 was preferentially occupied in the decreasing order by oleoyl > palmitoyl > stearoyl residues, the order in saturated TAGs being myristoyl > stearoyl = palmitoyl. TAGs in egg yolk were more asymmetric than in chicken skin, with linoleic acid highly specifically attached in the yolk sn-2 carbon. Nearly 50% of yolk TAGs contained 52 carbon atoms with two or three double bonds. Linoleic, oleic, and palmitic acids were in the sn-2 location in decreasing quantities in palm oil and its fractions. Triacylglycerols of equal molecular weight behaved similarly in the fractionation process. Randomization of the parent oil TAGs was seen in the transesterified oil. The tandem mass spectrometric analysis applied provided detailed information of the distribution of fatty acids in individual combinations in TAGs.     

Grain oil and fatty acids composition of soybean affected by nano-iron chelate,chemical fertilizers and farmyard manure

Applying organic sources has been recommended to increase soil fertility and crop growth in sustainable production systems. Less information is available on the effects of organic inputs on soybean oil quality in the presence of nano-iron chelate. Field experiments were conducted during 2012 and 2013 to investigate the impact of organic, nano- and chemical sources on oil content and fatty acid composition of soybean (Glycine max [L.] Merr.). In split-plot arrangement of treatments, the main plots consisted of four fertilization systems: (F1): cattle manure, (F2): chemical fertilizers, (F3): cattle manure + chemical fertilizers, and (F4): control (without fertilizers). The subplots were (N1): soybean treated with nano-iron chelate fertilizer and (N2): control. Results showed that the highest oil yield was obtained in F3 treatment. The application of farmyard manure with nano-iron chelate significantly increased oleic acid compared to chemical fertilizers. The highest stearic acid and linolenic acid were observed in chemical fertilizer-contained treatments. Finally, the organic manure increased the oil quality of soybean.