流动相pH对苯甲酸等5种食品添加剂反相高效 液相色谱行为影响及分析方法的建立

目的研究反相高效液相色谱中流动相pH值对苯甲酸、山梨酸、脱氢乙酸、安赛蜜和糖精钠等5种食品添加剂色谱行为的影响。方法调节流动相甲醇-乙酸铵pH值,观察在不同品牌色谱柱中苯甲酸等5种化合物保留时间、分离度。结果在流动相pH=6.20±0.05条件下梯度洗脱,10个品牌的C_(18)色谱柱验证结果表明,苯甲酸等5种化合物均实现了基线分离。5种食品添加剂在0.10～100.0mg/L范围内线性关系良好(r~20.999),检出限和定量限分别为0.004～0.008 mg/L、0.01～0.04 mg/L。食品添加剂在调味品、肉制品类等6种基质中回收率范围为90.6%～109.0%,相对标准偏差为0.2%～7.2%。结论该方法具有稳定性强、准确、易操作且不需要刻意选择亲水性C_(18)色谱柱,适用于调味品、肉制品类等复杂基质的样品添加剂的检测。     

高效液相色谱法同时测定酱腌菜中防腐剂和甜味剂

建立了酱腌菜中安赛蜜、苯甲酸、山梨酸、糖精钠4种食品添加剂的高效液相色谱同时测定方法。采用C18色谱柱,甲醇+0.02mol/L乙酸铵(4+96)为流动相,流速1.0mL/min,柱温25℃,二极管阵列检测器,检测波长230nm。结果表明:该方法4种添加剂回归方程线性关系良好,相对标准偏差在4.5%以下,回收率在89.6%~105.9%之间。该方法简便快速,准确可靠,可用于各类酱腌菜中安赛蜜、苯甲酸、山梨酸、糖精钠含量的同时测定。     

HPLC法同时测定葵花籽中苯甲酸、山梨酸、糖精钠3种添加剂

目的：建立一种高效液相色谱法同时测定葵花籽中苯甲酸、山梨酸、糖精钠3种食品添加剂的检测方法。方法：利用Agilent ZORBAX SB-C18色谱柱（250 mm*4.6 mm,5μm）、可变波长紫外检测器（VWD）进行检测，进样量：10μL；流速1.0 mL/min；检测波长：230 nm；甲醇—0.02 mol/L乙酸铵溶液为流动相；外标法进行定量分析。通过优化高效液相色谱条件，确定流动相，设置流动相的不同比例、不同流速，确定检测波长，进行分析。结果：苯甲酸、山梨酸、糖精钠3种添加剂可以得到很好的分离，在1.0～100.0μg/mL范围内具有良好的线性关系，相关系数均大于0.99，加标回收率为：96.14%～99.36%，相对标准偏差（RSD）为：0.02%～0.04%。结论：本实验方法简单高效，重复性好，操作容易，可以用于食品中葵花籽的山梨酸、苯甲酸、糖精钠3种食品添加剂的含量测定。     

超高效液相色谱-变波长法快速检测糕点中6种食品添加剂

摘 要：目的 建立一种快速的超高效液相色谱(ultra performance liquid chromatography，UPLC)-二极管阵列变波长检测方法，在10 min内同时测定糕点中安赛蜜、糖精钠、苯甲酸、山梨酸、脱氢乙酸和纳他霉素6种食品添加剂。方法 样品经20%甲醇水溶液(含2 mmol/L甲酸)提取，乙酸锌、亚铁氰化钾沉淀蛋白，以甲醇和20 mmol/L乙酸铵溶液(含2 mmol/L甲酸)作为流动相梯度洗脱，使用Agilent Poroshell 120 EC-C18 (4.6 mm×100 mm, 2.7 μm)色谱柱分离，二极管阵列-变波长检测。结果 6种食品添加剂在0.1~100 μg/mL范围内线性关系良好，相关系数均大于0.999，回收率为83.0%~110.2%，相对标准偏差(relative standard deviations, RSDs)为0.56%~5.96%。安赛蜜、糖精钠、苯甲酸、山梨酸、脱氢乙酸和纳他霉素的检出限为0.11~0.29 mg/kg，定量限为0.38~0.97 mg/kg。结论 该方法前处理简单，分析时间短，重现性好，适合用于糕点大批量检测。     

反相HPLC同时快速测定茶饮料中的安赛蜜、苯甲酸、山梨酸和糖精钠

建立了茶饮料中安赛蜜、苯甲酸、山梨酸和糖精钠四种食品添加剂的高效液相色谱测定方法,色谱条件为:色谱柱:Hypersil ODS C18(150mm×4.6mmi.d.,5μm);流动相:0.02mol/L乙酸铵溶液—甲醇(95:5,v/v);检测波长:230nm;流速:1.00ml/min;柱温:25℃;进样体积:10μl。本方法具有样品预处理简单、分析时间短等特点,可同时检测茶饮料中四种食品添加剂。     

高效液相色谱法检测果蔬汁中五种添加剂

目的:运用高效液色谱法对果蔬汁中苯甲酸、安赛蜜、脱氢乙酸、糖精钠以及山梨酸添加剂进行检测。方法:色谱柱:Kromasil 100-5 C18(250mm×4.6mm,5μg);流动相:甲醇∶0.02mol/L乙酰胺溶液=5∶95(V∶V);流速:1.0m L/min;进样量:20μL;柱温:30℃;波长:230nm。结果:苯甲酸、安赛蜜、脱氢乙酸、糖精钠以及山梨酸在0.00~0.1mg/m L浓度范围内,均表现为良好的线性关系(r=0.97、r=0.98、r=0.96、r=0.98、r=0.98)。山梨酸、安赛蜜、糖精钠、苯甲酸、脱氢乙酸RSD分别为1.13%、1.01%、1.51%、1.05%、1.18%;平均回收率分别为98%~99%。结论:在液果蔬汁添加剂检测中,高效液相色谱法快速准确,且灵敏度较高,可满足检查需要。     

HPLC法测定凉拌菜中苯甲酸、山梨酸和糖精钠的含量

建立HPLC法测定凉拌菜中苯甲酸、山梨酸和糖精钠含量的方法。色谱柱为Thermo AcclaimTM C18(250mm×4.6mm,5μm);流动相:甲醇-0.02mol/L乙酸铵溶液(10∶90);流速:1.0mL/min;检测波长:230nm;柱温:35℃。结果表明:该方法具有良好的精密度与稳定性,苯甲酸、山梨酸和糖精钠分别在0.457~18.28,0.214~8.576,0.40~16.00μg/mL范围内线性良好,其平均回收率分别为101.73%,98.65%,99.79%。实验结果表明该方法简便、结果准确、重现性好,用于凉拌菜中苯甲酸、山梨酸及糖精钠的含量测定,为凉拌菜中添加剂的检测奠定了基础。     

全自动固相萃取-超高效液相色谱-串联质谱法测定果酒中14种有机酸

目的 基于全自动固相萃取-超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mss spectrometry ,UPLC-MS/MS)建立果酒中14种有机酸的检测方法。方法 采用MAX固相萃取小柱净化,Agilent Eclipse Plus RRHD C18柱(3.0 mm×150 mm,1.8 μm)分离,0.4%甲酸溶液-乙腈为流动相梯度洗脱,电喷雾离子源负离子(ESI_-⁾模式下,结合动态多反应监测模式,外标法定量。结果 14种有机酸在各自的线性范围内相关系数均大于0.991,方法的检出限为0.7~50 μg/L ,方法的定量限为2~150 μg/L,回收率为82.6%~117.1% ,相对标准偏差为0.6%~8.7%(n=6)。结论：该方法操作简单,灵敏,重现性好,适用于果酒中有机酸的定性定量测定。     

HPLC法同时快速测定酱油中的苯甲酸、山梨酸、糖精钠、安赛蜜

建立了一种同时快速测定酱油中苯甲酸、山梨酸、糖精钠、安赛蜜的高效液相色谱法。样品经水提取,取离心后的上清液,过0.22μm滤膜,高效色谱仪(C18柱)分析。色谱条件:色谱柱为C_(18)柱,柱温35℃,流动相为甲醇-0.02mol/L乙酸铵(体积比为5∶95),流速1.0mL/min,二极管阵列检测器检测,以保留时间定性,外标法峰面积定量。结果表明,样品在10～100mg/kg添加水平范围内,苯甲酸、山梨酸、糖精钠、安赛蜜的回收率在90%～104%,相对标准偏差小于3%。该方法简便、准确,适用于酱油中苯甲酸、山梨酸、糖精钠、安赛蜜的快速检测。     

高效液相色谱法同时测定食品中山梨酸、苯甲酸、糖精钠、安赛蜜的方法研究

采用色谱柱Shimadzu VP-ODS,150×4.6,5μm,对缓冲溶液pH,流动相各组份比例进行了研究,实现了山梨酸、苯甲酸、糖精钠、安赛蜜四种常用添加剂8分钟内同时、快速、准确检测.色谱条件为:流动相A:0.02mol/L乙酸铵溶液(pH＝6.5),B:甲醇,15%B;流速,1.2mL/min;检测波长230nm.加样回收率试验山梨酸、苯甲酸、糖精钠、安赛蜜的回收率分别为100.03%、99.75%、98.88%、101.4%,RDS＜5%.试验结果表明,此法不仅定量准确、精密度高而且操作极为方便.     

Determination of ethanol,volatile fatty acids,lactic and succinic acids in fermentation liquids by gas chromatography

A rapid and simple quantitative method was developed to determine, by gas chromatography, the concentrations in fermentation liquids of ethanol, the C₂-C₆ volatile fatty acids, and lactic and succinic acids. Aqueous samples were acidified with 250μlml^?1 metaphosphoric acid (5:1 ratio), centrifuged, and injected directly on to a column containing a porous aromatic polymer (Chromosorb 101) maintained at 200°C in a gas chromatograph fitted with a flame ionisation detector. It was unnecessary to purify samples further before injection, although distillation and ion-exchange methods were examined. Derivatisation of lactic and succinic acids before injection was not necessary, but the lowest level of detection of these two relatively non-volatile acids was about four times greater than that for the volatile fatty acids. The method described was suitable for the analysis of rumen fluid, methane digester fluid, silage extracts and other anaerobic fermentation fluids. The relative retention times are given for 23 organic acids and six other fermentation end-products.     

Short communication: Eicosatrienoic acid and docosatrienoic acid do not promote vaccenic acid accumulation in mixed ruminal cultures

Previous research found that docosahexaenoic acid (C22:6n-3) was a component of fish oil that promotes trans-C18:1 accumulation in ruminal cultures when incubated with linoleic acid. The objective of this study was to determine if eicosatrienoic acid (C20:3n-3) and docosatrienoic acid (C22:3n-3), n-3 fatty acids in fish oil, promote accumulation of trans-C18:1, vaccenic acid (VA) in particular, using cultures of mixed ruminal microorganisms. Treatments consisted of control, control plus 5 mg of C20:3n-3 (ETA), control plus 5 mg of C22:3n-3 (DTA), control plus 15 mg of linoleic acid (LA), control plus 5 mg of C20:3n-3 and 15 mg of linoleic acid (ETALA), and control plus 5 mg of C22:3n-3 and 15 mg of linoleic acid (DTALA). Treatments were incubated in triplicate in 125-mL flasks, and 5 mL of culture contents was taken at 0 and 24 h for fatty acid analysis by gas-liquid chromatography. After 24 h of incubation, the concentrations of trans-C18:1 (0.87, 0.88, and 0.99 mg/culture), and VA (0.52, 0.56, and 0.62 mg/culture) were similar for the control, ETA, and DTA cultures, respectively. The concentrations of trans-C18:1 (5.51, 5.41, and 5.36 mg/culture), and VA (4.78, 4.62, and 4.59 mg/culture) were also similar between LA, ETALA, and DTALA cultures, respectively. These data suggest that C20:3n-3 and C22:3n-3 are not the active components in fish oil that promote VA accumulation when incubated with linoleic acid.     

Effects of abomasal infusions of fatty acids and 1-carbon donors on apparent fatty acid digestibility and incorporation into milk fat in cows

Our primary objective was to determine the effects of the abomasal infusion of 16-carbon (16C) and 22-carbon (22C) fatty acids (FA) on apparent FA digestibility, plasma FA concentrations, and their incorporation into milk fat in cows. Our secondary objective was to study the effects of 1-carbon donors choline and l-serine on these variables. Five rumen-cannulated Holstein cows (214 ± 4.9 d in milk; 3.2 ± 1.1 parity) were enrolled in a 5 × 5 Latin square experiment with experimental periods lasting 6 d. Abomasal infusates consisted of (1) palmitic acid (PA; 98% 16:0 of total fat), (2) PA + choline chloride (PA+CC; 50 g/d of choline chloride), (3) PA + l-serine (PA+S; 170 g/d of l-serine), (4) behenic acid (BA; 92% 22:0 of total fat), and (5) docosahexaenoic acid algal oil (DHA; 47.5% DHA of total fat). Emulsions were formulated to provide 301 g/d of total FA and were balanced to provide a minimum of 40 and 19 g/d of 16:0 and glycerol, respectively, to match the content found in the infused algal oil. Apparent digestibility of FA was highest in DHA, intermediate in PA, and lowest in BA. Digestibility of 16C FA was lowest in BA and highest in PA. The digestibility of 22C FA was highest in DHA relative to BA (99 vs. 58%), whereas 1-carbon donors had no effect on 22C FA digestibility. Plasma 16C FA concentrations were greatest with PA treatment, and 22C FA concentrations were ~3-fold greater in DHA-treated cows relative to all other treatments. Milk fat 16:0 content was highest in PA relative to BA and DHA (e.g., 37 vs. 27% in PA and DHA), whereas the milk yield of 16:0 was higher in PA relative to DHA (i.e., 454 vs. 235 g/d). Similarly, milk 22:0 content and yield were ~10-fold higher in BA relative to all other treatments, whereas DHA treatment resulted in higher content and yield of 22:6 in milk fat relative to all other treatments (41- and 38-fold higher, respectively). Consequently, the content of FA >16C (i.e., preformed) was higher in milk fat from cows infused with BA and DHA relative to PA. De novo FA content in milk did not differ between PA, PA+CC, and PA+S (~16% of milk fat) but was higher in BA and DHA treatments (19 and 21%, respectively). We conclude that FA carbon chain length and degree of saturation affected FA digestibility and availability for absorption as well as their incorporation into milk fat. The abomasal infusion of choline chloride and l-serine did not modify these variables relative to infusing palmitic acid alone.     

奶粉脂肪酸与乳制品风味关系研究

用气质（GC—MS）联用色谱分析了11个商业奶粉样品的脂肪酸组成以及含量,每个样品均检测到了28种脂肪酸,在表现奶粉风味的4个呈味脂肪酸,也即辛酸、己酸、壬酸和葵酸中只检测到了辛酸和葵酸。辛酸和葵酸含量在进口奶粉中普遍高于国产奶粉。国产奶粉中辛酸和葵酸的含量以2号最好,3号其次。亚油酸含量在国产奶粉中普遍高于进口奶粉。     

气相色谱法同时快速测定食品中丙酸、山梨酸、苯甲酸及脱氢乙酸

通过液液萃取净化样品研究,建立了食品中丙酸、山梨酸、苯甲酸、脱氢乙酸及其盐含量气相色谱同时快速测定方法,适用于固体非酯(脂)类食品的检测。结果表明:丙酸的回收率在85.1%~91.3%之间,其余3种防腐剂的回收率均在95.2%~99.4%之间;实验室内变异系数(CV,n=6)最大值≤4.7%,4种防腐剂检出限均在0.002 g/kg以下。4种目标物在有杂质干扰时,可用不同的极性毛细管柱做进一步的确认。本方法具有适用范围广、检测效率高、重现性好、准确度高、检出限低的特点,推广应用对我国食品安全的监督检验具有重要的意义。     

花生四烯酸、二十二碳六烯酸和二十碳五烯酸 在炎症中的作用概述

心脑血管疾病、肿瘤、糖尿病、神经系统疾病、自身免疫等疾病严重危害着人类的生命和健康,并消耗着大量医疗资源。事实上,很多疾病发生和发展的背后都伴随着炎症反应,炎症是众多疾病的病理基础,甚至是导致这些疾病的诱因。炎症本身是机体的防御性反应,但过度的炎症反应和长期慢性炎症会损害机体的稳态。炎症的调节和控制由炎症介质介导,花生四烯酸(arachidonic acid,AA)、二十二碳六烯酸(docosahexaenoic acid,DHA)和二十碳五烯酸(eicosapentaenoic acid,EPA)等长链多不饱和脂肪酸(10ng-chain polyunsaturated fatty acids,LC-PUFAs)的衍生物是一类重要的调控炎症的介质。炎性细胞间的交流和细胞内信号传递与LC-PUFAs有关。AA经环氧酶和脂氧合酶合成的类二十烷酸主要起促炎作用,但有的也有抗炎作用。DHA和EPA在体内起抗炎作用,由它们合成的消退素(resolvins,Rvs)和保护素(protectin,PD)是重要的抗炎活性物质。DHA和EPA还可以干扰炎性细胞内信号传导途径来抑制炎症反应。本文从炎症与疾病的关系、LC-PUFAs的衍生物及其促炎和抗炎机制等方面综述了AA、DHA和EPA在炎症中的作用。     

Growth of Aeromonas hydrophila K144 as Affected by Organic Acids

The influence of different acids on the aerobic growth kinetics of Aeromonas hydrophila was studied in BHI broth with 0.5 and 2.0% NaCl incubated at 5 and 19°C. Growth curve data were analyzed by the Gompertz equation and a nonlinear regression program; generation and lag times were calculated from the Gompertz parameters. Type of acid, pH, NaCl level and temperature influenced lag and generation times. The organic acids (acetic, lactic, citric and tartaric) inhibited growth at higher pH values than inorganic acids (HCl and H₂SO₄). The high NaCl level interacted with type of acid and pH to restrict growth of the organism at the lower temperature of incubation. Acetic and lactic acids were effective in controlling the growth of A. hydrophila and could readily be combined with low holding temperature to render foods free of the organism.     

Anti-obesity effects of conjugated linoleic acid, docosahexaenoic acid, and eicosapentaenoic acid

Obesity has become a prevailing epidemic throughout the globe. Effective therapies for obesity become attracting. Food components with beneficial effects on "weight loss" have caught increasing attentions. Conjugated linoleic acid (CLA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) belong to different families of polyunsaturated fatty acids (PUFA). However, they have similar effects on alleviating obesity and/or preventing from obesity. They influence the balance between energy intake and expenditure; and reduce body weight and/or fat deposition in animal models, but show little effect in healthy human subjects. They inhibit key enzymes responsible for lipid synthesis, such as fatty acid synthase and stearoyl-CoA desaturase-1, enhance lipid oxidation and thermogenesis, and prevent free fatty acids from entering adipocytes for lipogenesis. PUFA also exert suppressive effects on several key factors involved in adipocyte differentiation and fat storage. Despite their similar effects and shared mechanisms, they display differences in the regulation of lipid metabolism. Moreover, DHA and EPA exhibit "anti-obesity" effect as well as improving insulin sensitivity, while CLA induces insulin resistance and fatty liver in most cases. A deeper and more detailed investigation into the complex network of anti-obesity regulatory pathways by different PUFA will improve our understanding of the mechanisms of body weight control and reduce the prevalence of obesity.     

酸味酿造产品中三酸比例评析

酸味酿造产品中乳酸、醋酸、丁酸共存,但比例不同形成的酸味特征也不同。控制不同的环境条件,创造出不同的微生物区系,形成不同的三酸比例,才能形成不同的产品风格。该文对常见的酸味酿造产品中微生物区系的变化及三酸含量进行了分析。     

杂多酸催化合成辛酸蔗糖酯

以蔗糖、辛酸为原料,杂多酸为催化剂合成辛酸蔗糖酯。用L16(45)正交设计优化实验,高效液相色谱法分析反应液组成。考察了催化剂种类和用量、反应温度、原料配比、反应时间等因素对辛酸蔗糖酯产率的影响,发现以二甲基亚砜为溶剂、蔗糖与辛酸摩尔比1∶9、磷钨酸用量为蔗糖质量的2.0%、110℃反应时间6h,蔗糖转化率达60%,产物产要是二酯。动力学研究发现,蔗糖反应级数为一级,反应表观速率常数为0.0059min-1(90℃)、0.0117min-1(110℃),反应表观活化能Ea=39.57kJ/mol。