柱层析法分离大豆磷脂

通过实验探讨了使用低压制备色谱柱在等度洗脱方式下分离大豆磷脂中的磷脂酰肌醇(PI)、磷脂酰乙醇胺(PE)、磷脂酰胆碱(PC)等成分.结果表明,在使用100cm×26 mm规格的色谱柱、氯仿-甲醇(2∶1)作为流动相、流速控制在3.0 mL/min,负载量为0.25 g/150 g硅胶(100～200目)的条件下可以分离得到PI纯度在90%以上、PE纯度在80%以上、PC纯度在95%以上的各种产品.     

基于UPLC-Triple-TOF MS/MS对巴氏杀菌乳中磷脂成分的分析

基于超高效液相色谱-串联四极杆飞行时间高分辨质谱（ultra-high performance liquid chromatography-triple quadrupole-time of flight tandem mass spectrometry,UPLC-Triple-TOF MS/MS）法对巴氏杀菌乳中的磷脂成分进行分析鉴定。采用色谱柱ACQUITY UPLC? BEH C18（2.1 mm×100 mm,1.7 μm）,以流动相A水-甲醇-乙腈（1∶1∶1,V/V）和流动相B异丙醇-乙腈（1∶1,V/V）进行梯度洗脱,在电喷雾电离正模式下采集数据。依据高分辨质谱提供的保留时间、准分子离子、二级碎片等脂质分析数据,并结合标准品碎裂方式等信息,共鉴定出磷脂分子68 种。其中,磷脂酰胆碱22 种,占比7.98%;磷脂酰乙醇胺17 种,占比56.60%;磷脂酰丝氨酸10 种,占比1.70%;磷脂酰肌醇7 种,占比1.33%;鞘磷脂12 种,占比32.39%。本研究采用灵敏度高、精密度及稳定性良好的UPLC-Triple-TOF MS/MS方法实现了对牛乳中磷脂的全面定性与定量分析。此方法检测出的牛乳磷脂信息完整、磷脂种类多于其他检测技术,可为牛乳的磷脂研究提供数据基础。     

高效液相色谱法测定磷脂软胶囊中磷脂酰胆碱、磷脂酰肌醇、磷脂酰乙醇胺的含量

目的建立高效液相色谱法同时检测磷脂软胶囊中磷脂酰胆碱(phosphatidyl cholines, PC),磷脂酰乙醇胺(phosphatidyl ethanolamine, PE),磷脂酰肌醇(phosphatidylinositol, PI)3种组分的含量。方法样品用甲醇超声提取后,经Bridge?HILIC色谱柱(4.6 mm×150 mm, 5μm)分离,以0.9 mmol/L甲酸铵溶液-乙腈为流动相进行梯度洗脱,流速为1.0 mL/min;柱温30℃;检测波长为205 nm,外标法定量。结果磷脂酰胆碱,磷脂酰乙醇胺,磷脂酰肌醇在浓度0.025～0.250mg/mL范围内线性关系良好,相关系数均大于0.99,检出限分为0.300～1.386 mg/g,定量限为1.002～4.624 mg/g,加标回收率分别为90%～105%,相对标准偏差为1.0%～4.0%。结论该方法高效,便捷,准确度高,适用于磷脂软胶囊中3种磷脂成分的同时检测。     

高效液相色谱法测定大豆磷脂类保健食品中的磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰肌醇

目的建立高效液相色谱检测法测定大豆磷脂类保健食品中磷脂酰胆碱(phosphatidylcholines,PC)、磷脂酰乙醇胺(phosphatidylethanolamine, PE)、磷脂酰肌醇(phosphatidylinositol, PI)含量的方法。方法大豆磷脂类保健食品试样经正己烷:异丙醇(1:1, V:V)提取,经氨基柱(250 mm×4.6 mm, 5μm)分离,以流动相为无水乙醇-乙腈-水(50:40:10, V:V:V)为流动相等度洗脱,流速为0.4 mL/min,检测波长为205 nm,外标法定量。结果磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰肌醇在一定浓度范围内线性关系良好,相关系数大于0.999;检出限分别为1.3、5.0、1.0 mg/g,加标回收率分别为95.5%、99.5%、94.9%,精密度均为0.3%。结论本方法准确度高、重复性好,适用于保健食品中磷酯类物质含量的测定。     

直接进样HPLC-ELSD法测定花生中磷脂含量

建立了直接进样高效液相色谱-蒸发光检测器(HPLC-ELSD)法测定花生中磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、磷脂酰肌醇(PI)和磷脂酸(PA)的方法。采用改良Folch方法提取样品总脂肪,然后将提取出的总脂肪直接溶于流动相进行液相色谱分析,以L-Si型正相硅胶色谱柱(250 mm×4.6 mm,5μm)为固定相,以正己烷-异丙醇(体积比2∶3)为流动相A,正己烷-异丙醇-25 mmol/L乙酸铵溶液(体积比3.6∶5.4∶1)为流动相B进行二元梯度洗脱,蒸发光检测器检测。PC、PE、PI和PA 4种磷脂色谱峰面积与其质量浓度的线性相关系数(R2)大于0.995,4种磷脂的平均回收率在93.59%108.57%之间,RSD均小于10%。该方法具有重现性好、稳定性高、前处理简单的特点,可应用于磷脂的分离检测。     

哈维氏弧菌磷脂酶D对不同磷脂单分子层的吸附动力学研究

基于单分子层技术研究了哈维氏弧菌来源磷脂酶D(Vh PLD)对不同磷脂单分子层的吸附动力学。探究初始表面压力条件对VhPLD吸附不同磷脂单分子层(磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、磷脂酰丝氨酸(PS)、磷脂酰甘油(PG)和磷脂酰肌醇(PI))吸附动力学参数(k_a、k_d、K_(Ads))的影响规律。结果表明:VhPLD对磷脂单分子层的吸附动力学参数与磷脂单分子层初始表面压力密切相关;在15 m N/m条件下,VhPLD对不同磷脂单分子层吸附偏好性顺序为PC PG PS PE=PI;在20 m N/m条件下,VhPLD对不同磷脂单分子层吸附偏好性顺序为PG PI PC PS PE;在25 m N/m条件下,VhPLD对不同磷脂单分子层吸附偏好性顺序则转变为PC PS PI PE=PG。     

高效液相色谱-蒸发光散射法分析海鲈肌肉磷脂组成

对海水鱼海鲈肌肉磷脂的脂肪酸组成进行了测定,并建立了利用高效液相色谱-蒸发光散射法(HPLC-ELSD)分析其磷脂组成的方法。采用ChromolithPerformance-Si型正相硅胶色谱柱(100 mm×4.6 mm)进行磷脂组分分离,流动相为正己烷-异丙醇-乙酸体系,三元梯度洗脱,流速为1.5 m L/min,以各磷脂组分保留时间定性,峰面积定量。结果表明:海鲈肌肉磷脂不饱和脂肪酸含量为62.59%,EPA和DHA总含量达30.86%。采用HPLC-ELSD,磷脂组分分离效果良好,精密度高,变异系数均小于3%,平均回收率为86.00%～105.00%,相对标准偏差小于3.50%,此方法测定海鲈肌肉磷脂组成准确、高效,可运用于其他如海水鱼磷脂的分析检测。海鲈肌肉包含6种磷脂组分,其中磷脂酰乙醇胺(PE)含量最高,磷脂酰胆碱(PC)和磷脂酰肌醇(PI)次之。     

不同体长南极磷虾的脂质组成差异分析北大核心CSCD

旨在为南极磷虾渔业捕捞以及陆基精准加工利用提供科学指导,研究了不同体长南极磷虾的脂质组成差异。以脂质含量、甘油酯含量、磷脂含量、胆固醇含量、游离脂肪酸含量、磷脂组成和脂肪酸组成为评价指标,结合多元统计分析技术比较不同体长(<30 mm、30~40 mm、40~50 mm、>50 mm)南极磷虾脂质组成的差异。结果显示:不同体长南极磷虾脂质含量占干基的(17.57±2.43)%~(24.35±0.31)%;甘油酯和磷脂是主要的脂质组分,分别占脂质的(41.40±1.22)%~(43.54±2.02)%和(39.70±0.70)%~(41.89±2.69)%;磷脂主要由磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)和溶血磷脂酰胆碱(LPC)组成,分别占总磷脂的(80.04±0.73)%~(85.94±0.58)%、(13.13±0.59)%~(19.17±0.75)%、(0.79±0.05)%~(1.16±0.03)%;脂质中主要脂肪酸为C14∶0、C16∶0、C18∶1、C20∶5(EPA)、C22∶6(DHA),分别占总脂肪酸含量的(12.00±0.37)%~(12.85±0.15)%、(24.64±0.15)%~(27.11±0.16)%、(13.21±0.35)%~(15.09±0.14)%、(18.41±0.18)%~(18.86±0.56)%、(10.17±0.18)%~(12.84±0.16)%;不同体长南极磷虾的脂质含量、磷脂中PC和PE比例、脂肪酸中C16∶0、C18∶1和DHA比例等总体差异显著(p<0.05)。结合聚类分析和主成分分析,根据体长可将南极磷虾样品明显区分为<30 mm、30~40 mm、>40 mm 3大类。研究结果表明南极磷虾的脂质组成与其体长关系显著。     

WSL——改性磷脂的研究及其在化妆品中的应用

<正> 一、前言磷脂是一种脂质,是一种优良天然界面活性剂。脂质是广泛存在于生物体并能从有机溶剂抽提的脂肪以及类似脂肪化合物的统称。脂质可分为单纯脂质,复合脂质和衍生脂质。复合脂质由脂肪酸和醇类及其它物质化合而成,包括磷脂、糖脂、硫脂和氨基脂等。在工业上称卵磷脂为磷脂酰胆碱(PC)磷脂酰乙醇胺(PE)磷脂酰肌醇(PI)等磷脂和甘三酯(中性油)的混合物。在化学术语中,称磷脂酰胆碱为卵磷脂,称磷脂酰乙醇胺为脑磷脂。     

豆粕中残余脂质的提取与分析

豆粕中含有部分正己烷未能去除的残余脂质,采用体积比为2∶1的氯仿-甲醇溶液及水饱和正丁醇从豆粕中提取残余脂质,并对残余脂质成分进行了分析.传统的氯仿-甲醇溶液法可以将豆粕中大部分脂质提取出来,而与蛋白结合能力较强的极性脂需要进一步通过强极性的水饱和正丁醇提取.研究结果显示,豆粕中总脂质含量为2.10％,其中中性脂占25.24％,极性脂占74.76％,中性脂主要包括甘油三酯、FFA、甘油二酯;极性脂主要包括磷脂酰胆碱(PC)、磷脂酰肌醇(PI)、磷脂酰乙醇胺(PE)、磷脂酸(PA).     

展示设计的审美欣赏与价值取向

本文从影响展示效果的空间、平面、实物、多媒体、策划等因素出发,结合艺术活动的审美体验来展开其审美价值取向的阐述与探讨。     

食品抗氧化评价体系及其选择使用

目前有许多食品抗氧化能力评价方法,但是对于特定的食品该选择何种抗氧化评价方法还不确定,为了解决这个问题,主要介绍不同抗氧化评价方法的机理及其特点,以及它们在食品抗氧化评价体系中的选择作用。从体外、体内两个方面对食品抗氧化评价特点进行具体地介绍,以达到对食品抗氧化性的全面分析。值得推荐的是从血浆脂质过氧化水平和氧化应激生物标志物对食品的抗氧化能力进行分析。     

论家具设计创新与结构创新的关联性

家具设计创新可通过结构形式不断创新,新型五金配件的不断丰富,新型家具材料的不断发展,以及工艺技术的不断提高来实现,本文结合不同的家具结构形式分析其对家具造型创新的关系,来阐述家具结构创新对家具设计创新的重要性。     

Evaluation of a gas in vitro system for predicting methane production in vivo

Methane production from ruminant livestock varies with the diet as a result of factors such as dry matter intake, diet composition, and digestibility. To estimate the effect of dietary composition and feed additives, CH₄ production can be measured in vitro as a first step because large numbers of samples can be incubated and analyzed at the same time. This study evaluated a recently developed in vitro method for prediction of in vivo CH₄ production by examining the relationship between predicted and observed CH₄ production values. A total of 49 different diets (observations), used in previous 13 in vivo studies, were selected to include diets varying in nutrient composition. Methane production was measured in all in vivo studies by respiration chambers or the GreenFeed system (C-Lock Inc., Rapid City, SD). Overall, the in vitro system predicted CH₄ production well (R² = 0.96), but the values obtained were slightly underestimated compared with observed in vivo values (mean 399 L/d compared with 418 L/d: root mean square prediction error = 51.6 L/d or 12.3% of observed mean). Further analysis of the effect on residuals showed no significant relationship between CH₄ production and most factors known to affect CH₄ production such as dry matter intake, digestibility, and dietary concentrations of fat and starch. However, some factors included in the model were not well predicted by the system, with residuals negatively related to neutral detergent fiber concentration and positively related to concentrate proportion. The in vitro system can thus be useful for screening diets and evaluation of feed additives as a first step that can be best interpreted when feeding cows at maintenance level.     

In vitro versus in situ ruminal biohydrogenation of unsaturated fatty acids from a raw or extruded mixture of ground canola seed/canola meal

Raw or extruded blends of ground canola seeds and canola meal were used to compare in vitro and in situ lag times and rates of disappearance due to ruminal biohydrogenation of unsaturated fatty acids. The in situ study resulted in higher lag times for biohydrogenation for polyunsaturated fatty acids and lower rates of biohydrogenation of unsaturated fatty acids than the in vitro study, so the in situ biohydrogenation of polyunsaturated fatty acids was not complete at 24 h of incubation. With both methods, rates of biohydrogenation of polyunsaturated fatty acids were higher than for cis-delta9C18:1. Extrusion did not affect the rate of biohydrogenation of cis-delta9C18:1, but resulted in higher rates of biohydrogenation of polyunsaturated fatty acids with higher proportions of trans intermediates of biohydrogenation at 4 h of incubation in vitro and at 8 h of incubation in situ. These results suggest that extrusion affects the isomerization of polyunsaturated fatty acids, rather than the hydrogenation steps. In conclusion, in vitro and in situ methods can both show differences of ruminal metabolism of unsaturated fatty acids due to processing, but the methods provide very different estimates of the rates of disappearance due to biohydrogenation.     

蛋白质消化率测定方法的研究进展

对蛋白质消化率进行研究,不仅能使人们了解蛋白质的消化特性,而且对于研究蛋白质的营养价值具有重要的意义。为此,对国内外食品中蛋白质消化率测定的常用方法进行了综述与评价,并对各种蛋白质消化率测定方法的优缺点及适用的范围进行了讨论。     

Technical note: Methodological and feed factors affecting measurement of protein A,B, and C fractions,degradation rate,and intestinal digestibility of rumen-undegraded protein

When formulating dairy cow rations, characterization of protein in feeds requires estimation of protein degradation in the rumen and digestion in the intestine. The objective of this work was to evaluate experimental and feed-related factors that affect characterization using in situ, in vitro, or mobile bag techniques, of 0-h washout (A), potentially degradable (B), and undegradable (C) protein fractions, protein degradation rate (K_d), and digestibility of rumen undegradable protein (dRUP). Data sets of 136 studies on A, B, C, and K_d and 113 studies on dRUP were amassed from the literature. Mixed-effect linear models were used to relate these variables to methodological and feed factors while accounting for random differences among studies. Predictions of A, B, and C protein fractions were significantly influenced by crude protein and neutral detergent fiber interactions with bag pore size, incubation time, bag area, and sample-to-bag area ratio. For example, a 20.0% decrease in crude protein of a theoretical legume silage sample would increase A fraction prediction by 20.1%, but 34.7% with bag incubation time ?1 standard deviation below the mean. Similarly, reported K_d values were significantly influenced by crude protein interactions with bag area and sample-to-bag area ratio and by neutral detergent fiber interaction with pore size. Feed variables and measurement variables influencing protein digestibility measures suggest that these analytical factors are likely associated with variance among differing methodologies and within unique samples of the same feed. When predicting dRUP, the use of mobile bag method produced significantly different estimates compared with the in vitro 3-step method. The use of mobile bag resulted in an 8.9% (±3.8%) higher estimate of dRUP compared with the in situ technique. In 618 and 977 samples, sample variation to sample mean ratio for acid detergent fiber and pepsin-acid incubation time was 63.0 and 58.0%, respectively. Variation in feedstuff content and lack of standardization of methods used to measure protein disappearance led to a lack of robustness in the measurements commonly employed.     

电子烟基因毒性评价方法概述

为了解电子烟的基因毒性及其评价方法,按照受试对象分类进行了综述。其中以细菌为受试对象的试验方法有细菌回复突变试验和DNA损伤分析等;以离体细胞为受试对象的试验方法有微核试验、DNA双链断裂试验、RNA转录测序试验、定向基因检测分析和Bhas细胞转化试验等;以模式动物为受试对象的试验方法有长期吸入毒性试验和生殖发育毒性试验等;以人体为受试对象的主要是临床试验和流行病学调查研究等。由于受试对象和试验方法的差异性,导致电子烟基因毒性结果的可信度和可比性较差,因此建议在评价电子烟基因毒性的过程中,应至少考虑细菌、离体细胞、模式动物和临床试验等4个层次的受试对象,通过回复突变试验、微核试验、长期吸入毒性试验和临床试验等多种试验方法获得多个基因毒性的试验终点,科学、客观和全面地综合评价电子烟的基因毒性。