Photopyroelectric method for determination of thermophysical parameters and detection of phase transitions in fatty acids and triglycerides. Part I: Principles,theory, and instrumentational concepts

The photopyroelectric (PPE) technique is proposed to detect solid-to-liquid phase transitions in fatty acids and triglycerides. Various PPE configurations and cell geometries were used to obtain thermal parameters in the vicinity of the melting points for these samples. In the standard (SPPE) configuration used to determine specific heat, the sample is thermally thin and optically opaque, while the sensor itself is thermally thick. The same configuration, but with a thermally thick sample instead, allows direct measurement of the sample’s thermal diffusivity. The temperature dependence of the thermal effusivity was obtained for a thermally thick sample and a thermally thin sensor [inverse (IPPE) configuration], and for a semitransparent thermally thick sensor by making use of the front configuration.     

Comparative chemistry of elaiosomes of three species ofTrillium

This study was designed to compare the chemistry of elaiosomes of three sympatric species ofTrillium to discover if there are correlations between chemistry and dispersal rates by ants. We quantified the amount of proteins and neutral lipids and qualitatively analyzed the fatty acids occurring in triglyceride, diglyceride, monoglyceride, and free fatty acid fractions.T. grandiflorum had the highest lipid concentration per milligram of protein and the highest total lipid per elaiosome, followed byT. erectum and then byT. undulatum. Oleic acid (181) was abundant in all lipid fractions of each species. This fatty acid, which is responsible for corpse-carrying behavior in some ants, probably causes ants to pick up diaspores. Linoleic acid (182) is relatively abundant inT. erectum andT. grandiflorum but not inT. undulatum and may cause ants that have picked up diaspores to move (carry) those diaspores back to the nest. Total elaiosome mass and fatty acid composition appear to explain whyT. erectum is dispersed most rapidly and why ants that have picked up elaiosomes move moreT. grandiflorum thanT. undulatum diaspores.     

线性回归在糖尿病诊断中的应用

将数据挖掘技术应用到糖尿病的诊断之中,运用线性回归算法,对糖尿病患者体检的历史记录进行数据处理,分析糖化血红蛋白和甘油三酯与糖尿病之间的关系,以发现其中的医学诊断规则和模式,辅助医生进行疾病的诊断.根据数据挖掘的结果分析糖尿病患者的数据,得出结论：糖化血红蛋白和甘油三酯在人体内的含量越高,患糖尿病的概率就越大.     

几种非传统食用油脂甘三酯结构的研究

红花油、党参籽油、橄榄油、卡诺拉油和羊脂等五种油脂在我国的习俗上还很少作为食用,了解不多.对其进行甘三酯结构的研究将有助对该油脂等的充分利用.本文采用胰脂酶水解方法,以1,3—随机—2—随机分布假说计算其甘三酯组份,并以银离子薄层色谱法(俗称A_g~+—TLC)分离的情况作进一步验证,研究结果表明两者有较好的一致性.     

Kinetics of transesterification of soybean oil

Transesterification of soybean oil with methanol was investigated. Three stepwise and reversible reactions are believed to occur. The effect of variations in mixing intensity (Reynolds number=3,100 to 12,400) and temperature (30 to 70°C) on the rate of reaction were studied while the molar ratio of alcohol to triglycerol (6:1) and the concentration of catalyst (0.20 wt% based on soybean oil) were held constant. The variations in mixing intensity appear to effect the reaction parallel to the variations in temperature. A reaction mechanism consisting of an initial mass transfer-controlled region followed by a kinetically controlled region is proposed. The experimental data for the latter region appear to be a good fit into a second-order kinetic mechanism. The reaction rate constants and the activation energies were determined for all the forward and reverse reactions.     

Prepress solvent extraction of cuphea seed

Simulation of commercial processing of Cuphea seed to obtain needed quantities of oil and meal was accomplished with pilot facilities. Cuphea seed was conditioned in a single-deck cooker. Cooked seed was pressed with a mechanical screw with two-speed shaft, variable-speed drives and a four-section cage with cored sleeves. A feed rate of 22 kg seed/h and a feed screw-to-main shaft ratio of 2:1 gave good press cake with 8.1% residual oil. Press cake was extracted in a batch-type modular extraction pilot plant. Miscella stages were sequentially pumped through the beds, followed by hexane rinses. Spent cake was desolventized and toasted, and full miscellas were stripped to recover the crude oil. The finished Cuphea meal had only 0.30–0.55% residual oil. Thus, conditioned Cuphea seed was easily pressed without prior flaking to acceptable cakes, and conditions simulating commercial solvent extraction efficiently removed residual cake oil.     

Polyhydroxy fatty acids and their derivatives from plant oils

A novel process for the industrial production of hydroxylated fatty acids involves epoxidation of plant oils and their derivatives, followed by catalytic epoxy ring opening in the presence of water or other hydrogen donors, such as alcohols, diols, and amines. Depending on the starting material, epoxidation followed by opening of the oxirane ring leads to fatty acids that contain vicinal diol groups or to other substituted hydroxylated fatty acid derivatives. As an example for the preparation of a substituted hydroxylated fatty acid derivative, the reaction of epoxidized rapeseed oil with monobutylamine as hydrogen donor is described. Apart from the intended formation of hydroxyl groups with vicinal aminoalkyl groups, partial aminolysis of the ester compound was also observed. Another example describes the reaction of epoxidized rapeseed oil with different molar proportions of 1,4-butanediol as hydrogen donor. Depending on the molar proportion of the hydrogen donor, interesterification, or intermolecular ether formation were observed as side reactions. The properties of various technical hydroxylated fatty acids and their derivatives, prepared according to this novel process, are given, and potential applications of these products are suggested.     

Functional properties of butter oil made from bovine milk with experimentally altered fat composition

Modification of milk fat composition might be desirable to alter manufacturing characteristics or produce low saturated fat dairy products that more closely meet consumer dietary preferences. The aim of this research was to evaluate functional properties of butter oil obtained from milks with fat composition modified by altering the profile of long-chain fatty acids (FA) absorbed from the small intestine of cows. A control and 5 mixtures of long-chain free FA were infused into the abomasum of lactating dairy cows in a 6 × 6 Latin square design with 21-d periods. Treatments were 1) control (no FA infused), 2) mostly saturated FA (C₁₆:C₁₈ = 0.72), 3) low-linoleic palm FA (C₁₆:C₁₈ = 0.85), 4) palm FA (C₁₆:C₁₈ = 0.72), 5) soy FA (C₁₆:C₁₈ = 0.10), and 6) high-palmitic soy FA (C₁₆:C₁₈ = 0.68). All treatments included meat solubles and Tween 80 as emulsifiers. Solid fat content (from 0 to 40°C), melting point, and force at fracture were determined in butter oil. Milk fat from cows infused with palm FA (treatment 4) exhibited functionality equal to or better than control butter oil. Infusion with palm FA increased amounts of triglyceride (TG) fractions with 48, 52, and 54 carbon numbers but decreased TG with 32, 34, 36, and 42 carbon numbers. Infusion with soy FA increased TG with 26, 38, 40, 52, and 54 carbon numbers but decreased TG with 34, 42, and 46 carbons. Infusion of the mostly saturated FA increased TG with 38, 50, 52, and 54 carbon numbers but decreased TG with 32, 34, and 42 carbon numbers. These TG groups were consistently correlated with functional properties of butter oils from different treatments. The content of palmitic acid is important for maintaining functionality in the presence of increased polyunsaturated FA. The composition of milk fat may be able to be optimized through nutritional manipulation of diets for dairy cows if the optimal composition of FA and TG is defined for a particular dairy product.     

Direct Enzymatic Synthesis of Fatty Amines from Renewable Triglycerides and Oils

Fatty amines represent an important class of commodity chemicals which have broad applicability in different industries. The synthesis of fatty amines starts from renewable sources such as vegetable oils or animal fats, but the process has multiple drawbacks that compromise the overall effectiveness and efficiency of the synthesis. Herein, we report a proof-of-concept biocatalytic alternative towards the synthesis of primary fatty amines from renewable triglycerides and oils. By coupling a lipase with a carboxylic acid reductase (CAR) and a transaminase (TA), we have accomplished the direct synthesis of multiple medium and long chain primary fatty amines in one pot with analytical yields as high as 97 %. We have also performed a 75 mL preparative scale reaction for the synthesis of laurylamine from trilaurin, obtaining 73 % isolated yield.     

不同类型鱼油对维生素 A 醋酸酯稳定性的影响

目的通过添加不同类型鱼油,分析保健品中维生素A醋酸酯的降解情况。方法将配制好的鱼油样品在温度(37±2)℃,相对湿度(75±5)%的条件下放置6个月,分别在0、1、2、3、6个月取样,检测维生素A醋酸酯的含量。将检测结果与0个月比较,考察维生素A醋酸酯含量的变化。结果通过6个月的考察分析,乙酯型鱼油维生素A醋酸酯含量变化较大,甘油三酯型鱼油维生素A醋酸酯变化小,且乙酯型鱼油配方样品中维生素A醋酸酯的降解产物较杂。结论鱼油保健品在加速实验条件下放置6个月,不同结构的鱼油对维生素A醋酸酯含量的影响不同,甘油三酯型鱼油更稳定。