Solubilization of methanol and triglycerides: Unsaturated long-chain fatty alcohol/medium-chain alkanol mixed amphiphile systems

This work examines the suitability of unsaturated C₁₈ fatty alcohol/1-alkanol mixed amphiphile systems as solubility enhancers for methanol in triglyceride solutions. Four fatty alcohols (all-cis monoene, diene and triene, and all-trans diene) and five alkanols (C₄−C₁₂) were investigated. Effects of the degree of unsaturation and configuration of the double bonds in the fatty alcohol tailgroup and the chainlength of the alkanol tailgroup were examined. Ternary equilibrium diagrams showed that addition of fatty alcohol/alkanol amphiphiles dramatically affect miscibility between methanol and triglyceride. Solubility, kinematic and relative viscosity, and refractive index data were analyzed to determine mechanisms responsible for the apparent solubilization effects. Under most experimental conditions, formation of large micellar aggregates of amphiphiles was unlikely, and the results were consistent with those expected for co-solvency. However, some viscosity and refractive index data showed that formation of large methanol-in-amphiphile aggregates resembling a nonaqueous microemulsion was feasible, but under limited conditions.     

Body composition and serum and liver lipids in rats fed distillers' dried grains

This study examined the body composition and serum and liver lipids in weanling rats fed diets containing distillers' dried grains with solubles (DDGS) from either white wheat (WW), red wheat (RW), corn (CO) or WW fortified with essential amino acids (FWW) as a sole protein source (1.6 % N in the diet). Although the DDGS-fed groups had significantly lower body weights compared with the casein control (RC) after a 28-day feeding trial, there were no significant differences among the dietary groups in percentages of body water, protein, lipid or ash. Serum cholesterol was significantly higher in rats fed the RW diet, and serum triglyceride was higher in the RC and FWW groups compared with the other dietary groups. Liver cholesterol and triglyceride concentrations (mg g^?1 liver) were not significantly different among the five dietary groups.     

Molecular exchange in thermal equilibrium between dissolved and crystalline tripalmitin by NMR

An NMR technique to measure exchange kinetics at thermal equilibrium in dispersions of moderately soluble crystalline material is presented. By monitoring the exchange of molecules between pools in solid and dissolved form, one can characterize the surface specific exchange rate. Illustrative experiments were performed in a model system with β-type crystals of tripalmitin as the solid phase and tripalmitin, a fraction of it deuterated, dissolved in a medium-chain TG oil as the liquid phase. The concentration of deuterated tripalmitin in the solvent was followed by ²H NMR after the crystals, which initially lack deuterated tripalmitin, were immersed in the liquid. The variation of the ²H concentration in the solvent provided the surface specific exchange rate. No systematic errors, due to the slight difference in properties of the deuterated tripalmitin compared to hydrogenated tripalmitin, were observed. The methodology worked well between crystal concentrations of 2 and 4 wt%.     

The Influence of Lubricating Agents on the Formation of a Film of a Styrene/Butadiene Latex

The interactions between paper coating lubricants and a carboxylated styrene/butadiene latex emulsion and their effect on latex film morphology have been studied. Calcium stearate, non-ionic polyethylene emulsion and organic triglyceride lubricants showed different interaction characteristics with the latex emulsion according to viscosity, zeta potential and isothermal calorimetric measurements. Calcium stearate lowered the viscosity of the dilute latex emulsion at low concentration suggesting a strong interaction with the latex particles due to a change in the hydrodynamic dimensions of the latex particles. The exothermic enthalpy change supported the assumption of a dissociative interaction. In contrast, both non-ionic polyethylene and organic triglyceride emulsion showed less pronounced enthalpy changes, indicating lower affinity for the latex particles. The reduction in viscosity showed, however, that at low lubricant concentrations there is an interaction between the latex particles and particularly the organic triglyceride emulsion. This suggests a selective adsorption of stabilizing agents and species from the lubricant emulsion which alters the hydrodynamic radius of the latex particles. The effects of the colloidal interactions on the morphology of the latex films monitored by Atomic Force Microscopy (AFM) indicated that specific surface interaction occurring in aqueous media influenced the topography and the surface chemical heterogeneity of the latex films. Especially in the case of calcium stearate, it seems that the dissolved species arrange themselves around the latex particles inhibiting film formation. The organic triglyceride, on the other hand, showed a lower interaction potential in the aqueous phase and it had a different impact on the film formation.     

1,3-二油酸-2-棕榈酸甘油三酯的合成

为了解决1,3-二油酸-2-棕榈酸甘油三酯(OPO)合成过程中不利于脂肪酶活性发挥的问题,采用两步法合成OPO,首先以棕榈硬脂和高油酸葵花籽油为原料通过化学酯交换反应得到相对棕榈硬脂熔点降低的油脂,再以化学酯交换油脂与油酸为原料在Lipozyme RM IM脂肪酶催化下进行酶法酸解反应得到OPO。通过单因素实验及响应面优化实验确定最优反应条件为棕榈硬脂与高油酸葵花籽油质量比2∶1、化学酯交换油脂与油酸质量比1∶1.45、酶添加量4%、反应温度50.40℃、反应时间5.29 h,该条件下OPO含量为27.26%,sn-2位棕榈酸占总棕榈酸含量为67.36%。以棕榈硬脂为原料合成OPO的新工艺一方面提升了高油酸植物油的使用价值,另一方面酶法酸解反应的温度适中,更有利于脂肪酶活性发挥。     

Residual solvent or intrinsically formed during production: analysing volatile compounds in unrefined vegetable oils using headspace gas chromatography coupled with mass spectrometry

ABSTRACT

Vegetable oils are an essential part of a healthy and balanced diet and have major economic significance. The type of production, whether performed by extraction with solvents, or by mechanical techniques, significantly influences the quality of the oil and its potential field of use. Occasionally, volatile organic substances, which are considered indicative for an oil that has been produced by solvent extraction, are detected in unrefined vegetable oils. This can have a negative impact on high-quality oil mills and their reputation. The goal of the study was to analyse unrefined oils of different raw materials for such compounds. A previously developed and validated method using headspace gas chromatography coupled with a mass spectrometry was used for this task. Another aim was to determine the origin of any solvent residues in the vegetable oils and to find ways to avoid them. Complementary measurements by solid phase micro extraction gas chromatography were conducted to compare the results of the measurements to an orthogonal methodology. Multivariate data analysis was used to find correlations between the spectrum of substances in the oil and other parameters like the producer of the oil or the pattern of fatty acids.     

Evaluation of hypolipidemic effects of peanut skin-derived polyphenols in rats on Western-diet

The effect of water soluble polyphenolic extract of peanut skin (PE) was investigated for its hypolipidemic properties in rats on Western diet. Seven-weeks old Wistar rats received control diet (AIN-93G), Western diet with and without a bolus of PE five times a week for 10weeks. Group which received 300mg/kg body weight showed significantly reduced body weight and epididymal fat. Plasma and liver triglyceride (TG) and cholesterol (TC) levels were significantly reduced while faecal secretion of TG and TC was greatly increased upon PE administration. Liver mRNA expression of enzymes involved in fatty acid synthesis, such as fatty acid synthase (FAS), sterol receptor element binding protein (SREBP)-1c, acetyl-CoA carboxylase (ACC1) and lipid uptake genes, such as PPARγ, were decreased, while PPARα was up-regulated by administration of PE. These data suggest that administration of PE may contribute to the improved lipid homoeostasis in rats on diets high in cholesterol and lipids.     

反相高效液相色谱-大气压化学电离质谱分析猪脂甘油酯及调控氧化猪脂中极性非（难）挥发性物质

采用固相萃取-反相高效液相色谱-大气压化学电离质谱分析猪脂的甘油酯组成以及调控氧化工艺制备的氧化猪脂的极性非（难）挥发性物质组成。从猪脂中鉴定出33 种甘油酯,包括7 种甘二酯和26 种甘三酯,按总离子流色谱图中的相对峰面积,含量高的为1-棕榈酸-2-亚油酸-3-油酸甘三酯（16.13%）、1,3-二油酸-2-亚油酸甘三酯（15.25%）、1,3-二油酸-2-棕榈酸甘三酯（12.96%）、1-油酸-2,3-二亚油酸甘三酯（8.05%）。从调控氧化猪脂中鉴定出5 种甘二酯和由10 种甘三酯氧化形成的22 种单氢过氧化物,按总离子流色谱图中的相对峰面积,含量高的为1-硬脂酸-2-亚油酸-3-油酸甘三酯单氢过氧化物（18.44%）、1-棕榈酸-2-亚油酸-3-油酸甘三酯单氢过氧化物（16.03%）、1,3-二油酸-2-棕榈酸甘三酯单氢过氧化物（9.42%）、1,3-二油酸-2-亚油酸甘三酯单氢过氧化物（8.71%）、三油酸甘三酯单氢过氧化物（7.63%）、1-棕榈酸-2,3-二亚油酸甘三酯单氢过氧化物（7.53%）。结果表明,猪脂调控氧化主要对猪脂中含不饱和脂肪酸的甘三酯进行氧化,因形成的极性非（难）挥发性氧化产物仅检测到甘三酯单氢过氧化物。     

Palmitic Acid in Early Human Development

Palmitic acid (16:0) is a saturated fatty acid present in the diet and synthesized endogenously. Although often considered to have adverse effects on chronic disease in adults, 16:0 is an essential component of membrane, secretory, and transport lipids, with crucial roles in protein palmitoylation and signal molecules. At birth, the term infant is 13–15% body fat, with 45–50% 16:0, much of which is derived from endogenous synthesis in the fetus. After birth, the infant accumulates adipose tissue at high rates, reaching 25% body weight as fat by 4–5 months age. Over this time, human milk provides 10% dietary energy as 16:0, but in unusual triglycerides with 16:0 on the glycerol center carbon. This paper reviews the synthesis and oxidation of 16:0 and possible reasons why the infant is endowed with large amounts of fat and 16:0. The marked deviations in tissues with displacement of 16:0 that can occur in infants fed vegetable oil formulas is introduced. Assuming fetal fatty acid synthesis and the unusual delivery of 16:0 in human milk evolved to afford survival advantage to the neonate, it is timely to question if 16:0 is an essential component of tissue lipids whereby both deficiency and excess are detrimental.     

牛磺酸影响脂肪代谢的研究概况

牛磺酸是一种广泛存在于哺乳动物组织中的小分子含硫氨基酸,结构简单且不参与蛋白质合成,牛磺酸可由甲硫氨酸和半胱氨酸合成,也可以由饮食提供,富含于鱼贝类等海产品中,具有多种生理功能。动物实验和临床实验表明牛磺酸可显著改善肥胖,降低血清甘油三酯水平,减少肝脏脂肪蓄积。本文从动物实验、细胞实验、临床实验和流行病学调查四个方面总结了牛磺酸对脂肪代谢的影响,并主要从促进脂肪分解代谢、抑制脂肪合成、减少炎症反应和氧化应激、提高脂联素水平、与胆汁酸结合等方面归纳了牛磺酸影响脂肪代谢的作用机理,为进一步研究牛磺酸促进脂肪代谢的作用机制提供参考,也为开发以牛磺酸为功能因子、具有减肥、改善血脂及脂肪肝功能的保健品提供理论依据。