Optimization of Enzymatic Synthesis of Tricaprylin in Ionic Liquids by Response Surface Methodology

Ten 1,3‐dialkylimidazolium‐based ionic liquids (ILs) have been investigated as media for the enzymatic synthesis of tricaprylin, in comparison with the conventional organic solvent hexane. The results suggested that the esterification activity of Novozym 435 was higher than Lypozyme RM IM in all the ILs assayed. Novozym 435 showed higher catalytic activity in ILs with anions Tf₂N^? and PF₆^? than in BF₄^? and hexane. FTIR analysis of the secondary structure of the lipase indicated that a smaller decrease of the α‐helix was observed in [C₄MIM] Tf₂N and [C₄MIM] PF₆ than [C₄MIM] BF₄ and hexane, indicating that the anions of ILs might be a key factor for the activity of lipase in ILs. Process parameters (amount of lipase, caprylic acid/glycerol molar ratio, temperature and their interactive effects) were optimized in 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([C₄MIM]PF₆) using Novozym 435 by response surface methodology. When the reactions were performed with the lipase amount of 6.1 % substrate mass at a caprylic acid/glycerol molar ratio of 4.5:1 and 66.7 °C, a higher yield was reached up to 92.4 %.     

Physical State of β‐Carotene at High Concentrations in a Solid Triglyceride Matrix

The highly hydrophobic β‐carotene is often distributed or dissolved in triglycerides to enhance either nutritional or coloring effects. This study aims at elucidating the physical state of β‐carotene that at high concentrations are mixed into a solid high‐melting tri‐glyceride matrix by dissolution at high temperatures (165 °C) in the melted triglyceride. Extensive isomerization of β‐carotene is observed by HPLC after melting crystalline all‐trans β‐carotene and in the solid mixtures of β‐carotene and fully hydrogenated sunflower oil. Crystalline triglyceride is found in the mixed samples by XRPD analysis whereas no signs of crystalline lattice structures of β‐carotene are detected. DSC thermograms show only the melting and recrystallization events of triglycerides, which are affected by the presence of β‐carotene. Severe line broadening is observed in the ¹³C CP/MAS NMR spectra of the β‐carotene‐triglyceride mixtures when compared to crystalline β‐carotene, demonstrating the lack of long‐range order of the carotene. Altogether, the results demonstrate that β‐carotene is present as an amorphous mixture of trans‐ and cis‐isomers dispersed into a structure of crystalline triglyceride in the solid carotene‐triglyceride mixtures. Practical applications: The amorphous structure of trans‐ and cis‐isomers in solid formulations of β‐carotene‐triglyceride mixtures will strongly affect their functional properties related to nutrition and color as food ingredients.     

Essential Polyunsaturated Fatty Acids in Blood from Patients with and without Catheter-Proven Coronary Artery Disease

Coronary artery disease (CAD) is the leading cause of death worldwide. Statins reduce morbidity and mortality of CAD. Intake of n-3 polyunsaturated fatty acid (n-3 PUFAs), particularly eicosapentaenoic acid (EPA), is associated with reduced morbidity and mortality in patients with CAD. Previous data indicate that a higher conversion of precursor fatty acids (FAs) to arachidonic acid (AA) is associated with increased CAD prevalence. Our study explored the FA composition in blood to assess n-3 PUFA levels from patients with and without CAD. We analyzed blood samples from 273 patients undergoing cardiac catheterization. Patients were stratified according to clinically relevant CAD (n = 192) and those without (n = 81). FA analysis in full blood was performed by gas chromatography. Indicating increased formation of AA from precursors, the ratio of dihomo-gamma-linolenic acid (DGLA) to AA, the delta-5 desaturase index (D5D index) was higher in CAD patients. CAD patients had significantly lower levels of omega-6 polyunsaturated FAs (n-6 PUFA) and n-3 PUFA, particularly EPA, in the blood. Thus, our study supports a role of increased EPA levels for cardioprotection.     

金松酸对HepG2细胞中甘油三酯蓄积的影响

为探讨香榧金松酸(SA)对甘油三酯(TG)蓄积的影响及其作用机制,本研究以HepG2为模型细胞,首先采用MTT法确定油酸(OA)与SA的临界安全浓度,然后通过油红染色法观察细胞内脂质积累情况并定量测定了细胞内TG含量,最后利用RT-qPCR分析SA对细胞脂质代谢关键基因的影响。结果显示：OA和SA总添加量为500 mol/L,随着SA替换量从0%上升到100%,细胞内TG蓄积明显降低,从0.033 mmol/g减低到0.017 mmol/g;脂肪酸合成关键基因FAS、ACC1、SCD1、SREBP1的表达量分别降低了40.92%、62.01%、25.56%、43.79%,脂肪酸氧化关键基因SCD1、PPARα的表达量分别提高了143.94%、445.11%,TG分解基因ATGL的表达量增加了123.71%。因此,SA显著抑制了细胞TG蓄积,其可能机制是SA通过上调TG分解代谢关键酶同时下调TG合成代谢关键酶。作为天然食物成分,SA在减肥食品开发方面具有良好的应用前景。     

Lipozyme TL IM催化合成中长链脂肪酸甘油三酯的工艺优化

为探索高含量中长链脂肪酸甘油三酯(MLCT)和低成本的酶法催化合成MLCT工艺,以一级菜籽油为原料,采用脂肪酶Lipozyme TL IM酶法催化酯交换合成MLCT,采用单因素试验研究了底物配比(菜籽油与中链甘油三酯质量比)、反应时间、反应温度、酶添加量对酯交换反应的影响,在此基础上,通过正交试验对MLCT合成工艺条件进行优化。结果表明,最佳的MLCT合成工艺条件为底物配比3∶1、反应时间4 h、反应温度50℃、酶添加量8%(基于底物的质量),在此条件下MLCT含量达到87.50%。优化的MLCT合成工艺具有MLCT含量高,反应时间短、反应温度低的优势,可降低能耗及减少酶失活,从而降低了生产成本。     

芝麻油掺伪鉴别技术研究进展

芝麻油具有独特的香味以及丰富的营养价值和市场价值,因此掺伪现象非常严重。本文根据芝麻油中的特征成分性质、油脂中甘三酯及脂肪酸性质的差异,就目前芝麻油掺假检测技术研究进展进行综述,分析了这些检测方法的优缺点和影响因素,并对芝麻油掺伪检测技术的发展方向进行了展望。     

Physicochemical properties of cassava,potato and jicama starches oxidised with organic acids

The oxidising effects of organic (acetic, citric and lactic) acids on the physicochemical properties of starches from cassava, potato and jicama were investigated. Cassava starch oxidised with lactic and citric acids had the highest carbonyl contents (5.43 and 5.84 g kg^?1 respectively), while oxidised potato starch had the highest carboxyl contents. Oxidised jicama starch showed the lowest carbonyl and carboxyl contents. Oxidation increased the maximum viscosity of cassava starch (from 426.61 to 670.11 relative viscosity units (RVU)) and jicama starch (from 160.17 to 561.50 RVU) but decreased that of potato starch (from 669.44 to 206.92 RVU). When carbonyl and carboxyl groups were incorporated into jicama starch granules, the resistance of these granules to stirring at constant temperature (holding) increased, as did their final and retrogradation viscosities. However, the behaviour of oxidised cassava and potato starches, as indicated by a Rapid Visco Analyser, was different. The highest values of endotherm enlargement were found for native and oxidised jicama starch, while the lowest values were found for native and oxidised cassava starch. Native and oxidised potato starch had the highest enthalpy values (14.30–18.30 J g^?1), while jicama starch had the lowest (9.50–11.9 J g^?1). The high intrinsic viscosity of native potato starch was attributed to B‐type starch with a longer‐than‐average amylopectin chain length and a lower degree of crystallinity. Oxidised granules showed little erosion in the form of grooves; on the contrary, oxidation left the grains with a very smooth surface. Copyright © 2007 Society of Chemical Industry     

基于棕榈仁油的特医脂肪乳液制备及其对小鼠血脂的影响（网络首发、推荐阅读）

中链甘油三酯是特医脂肪组件的重要组成成分,棕榈仁油是其天然食物来源。为开发基于棕榈仁油的特医脂肪乳液产品,依据《特殊医学用途配方食品通则》《中国居民膳食营养素参考摄入量》等进行脂肪酸均衡型乳液油相配方设计,并分析其脂肪酸组成;以Zeta电位、粒径为指标优化脂肪乳液制备工艺,并对研发产品进行稳定性评价,通过小鼠试验研究其对血清血脂的影响。结果表明,油相不饱和脂肪酸中n–6与n–3比值为5.16±0.05;采用分步乳化法,最佳乳化工艺为乳化速度10 000 r/min,乳化时间20 min, 乳化温度50 ℃;初乳液经高压均质机50 MPa均质三次,121 ℃高压灭菌10 min,在上述条件下制备的脂肪乳液产品质量稳定。动物试验结果表明,该脂肪酸均衡型脂肪乳液具有显著降低小鼠血清甘油三酯（Triglycerides,TG）含量（P<0.01）、降低血清总胆固醇（Total cholesterol,TC）含量（P<0.01）,以及降低低密度脂蛋白胆固醇（Low-density lipoprotein cholesterol,LDL-C）含量（P<0.05）和升高高密度脂蛋白胆固醇（High-density lipoprotein cholesterol,HDL-C）含量（P<0.01）的作用,对于调节血脂水平具有一定意义。     

Analysis of soybean oil from Ohio

Five soybean cultivars-Pella 86, Ripley, Sherman, Williams 82, and Zane—were analyzed to determine the total fatty acid composition and triglyceride fatty acid composition. Palmitic, stearic, oleic, linoleic, and linolenic were the major fatty acids in these cultivars. Zane was significantly higher in saturated fatty acid content and lower in linolenic acid content than the other cultivars. Resolution by argentation thin-layer chromatography decreased with increased triglyceride unsaturation.     

牛油基起酥油的起砂原因初探

对牛油基起酥油的起砂部分与未起砂部分分别进行熔点、脂肪酸、甘三酯组成和差示扫描量热仪(DSC)分析,发现起砂部分的甘三酯组成有很大变化,低熔点甘三酯(POL、POO、SOO)含量下降,高熔点甘三酯(POP、POS、SOS)含量升高;起砂部分的DSC曲线趋于复杂。