Determination of dimethylformamide in food additive sucrose esters of fatty acids using solid-phase extraction

A simple method using Florisil cartridges was developed for the determination of dimethylformamide (DMF) in sucrose esters of fatty acids present in sugar esters (SuE) and sucrose acetate isobutyrate (SAIB) used as food additives. SuE was dissolved in acetone and loaded on a Florisil cartridge. SAIB was dissolved in hexane, loaded on a Florisil cartridge and washed with 10% acetone in hexane. The columns were eluted with acetone and DMF in the eluates was determined by GC with an FID detector. Recoveries of DMF at the level of 0.5-100 micrograms/g were 93.3-102.6%. The determination limit was 0.5 microgram/g.     

中药菲牛蛭中脂肪酸及微量元素的测定

通过改良的Folch氏脂质的提取法、湿法消化法分别提取了菲牛蛭中的脂肪酸和微量元素,并采用GC/MS(气相色谱/质谱)法和ICP-AES(等离子发射光谱)法,对菲牛蛭中所含的脂肪酸和微量元素含量进行测定。结果表明,菲牛蛭中含有16种脂肪酸和8种微量元素。     

豆豉中脂肪酸成分的GC/MS分析

为评价豆豉的营养价值并探讨其药用价值提供实验数据，利用气相色谱／质谱联用仪（GC／MS）对广东阳江豆豉中的脂肪酸成分进行了分析。检测出亚油酸、油酸、棕榈酸和硬脂酸等16种化合物的相对含量。其中不饱和脂肪酸占78．273％，饱和脂肪酸占6．496％，相对含量最高的是十八碳二烯酸（亚油酸），为55．941％。     

食用油中反式脂肪酸的气—质分析法研究

建立气相色谱—质谱法测定食用植物油中反式脂肪酸的分析方法。食用植物油中的脂肪酸甲酯化后,经强极性毛细管柱SP—2560分离,采用质谱全扫描Scan方式得到各组分质谱图与标准谱库做相似度检索来定性,面积归一化法定量。用所建立的方法测定了6种常见食用植物油中反式脂肪酸含量,该法测定食用植物油中的反式脂肪酸含量前处理简单、快...     

3种海参与3种贝类中脂肪酸及烯醚键基团的 气相色谱/质谱分析比较

本文研究了用气相色谱/质谱法测定比较3种海参与3种贝类脂肪酸及脂肪醛二甲基缩醛的方法。该6种原料经Folch法提取总脂,用10%硫酸-甲醇溶液对其进行甲酯化反应,通过气相色谱/质谱法对其脂肪酸及脂肪醛二甲基缩醛的组成进行分析。实验结果表明：10%硫酸-甲醇溶液能有效地对脂肪酸进行甲酯化衍生;同时促使烯醚键断裂,并与甲醇发生缩醛反应生成脂肪醛二甲基缩醛。通过气相色谱/质谱分析,从3种海参与3种贝类的气相色谱/质谱图中共鉴定出24种脂肪酸,海参中脂肪酸以C16:0,C16:1(n-7)和C20:4(n-6)为主;贝类中脂肪酸以C16:0,C20:5(n-3)和C22:6(n-3)为主;海参与贝类中脂肪醛二甲基缩醛均以C18:0DMA为主。海参和贝类中的脂肪酸及脂肪醛二甲基缩醛的组成与含量都相差较大。     

牦牛乳脂肪酸组成分析

乳脂的营养价值很高,牦牛乳中含有大量的脂肪酸,主要脂肪酸为辛酸、月桂酸、肉豆蔻酸、十五碳酸、棕榈酸、棕榈油酸、珍珠酸、硬脂酸、油酸、亚油酸、亚麻酸.目前脂肪的提取方法和甲酯化方法没有确定统一的方案,本研究对牦牛乳采用不同的脂肪提取方法和甲酯化方法,旨在找到分析牦牛乳中主要脂肪酸的最佳方案.乳脂肪酸的组成直接影响乳的营养、风味以及加工品质,乳脂肪酸功能及乳脂肪酸组成的调控成为当前反刍动物营养研究的热点,因此分析牦牛乳中脂肪酸的组成,对于认识其营养价值具有重要意义.     

核桃酱中脂肪酸成分的GC/MS分析

为评价核桃酱的营养价值并探讨其药用价值提供实验数据,利用气相色谱/质谱联用仪(GC/MS)对核桃酱中的脂肪酸成分进行了分析。检测出亚油酸、油酸、棕榈酸和硬脂酸等13种化合物的相对含量。其中不饱和脂肪酸占78.84%,饱和脂肪酸占20.28%,相对含量最高的是十八碳二烯酸(亚油酸),为53.14%。     

林蛙卵油脂肪酸组分的分析研究

林蛙卵经石油醚和超临界CO2流体萃取得到林蛙卵油。把林蛙卵油甲酯化,用石英毛细管色谱/质谱法测定其脂肪酸组分。采用石油醚方法萃取得到的林蛙卵油分离出19种组分,不饱和脂肪酸含量为72.38%;采用超临界CO2流体萃取得到的林蛙卵油分离出26种组分,不饱和脂肪酸含量为69.65%。研究结果表明:两种方式获得的林蛙卵油脂肪酸主要组分及含量基本一致,均由C12-22脂肪酸组成,主要不饱和脂肪酸是十六碳烯酸、亚油酸、油酸、EPA(二十碳五烯酸)、DHA(二十二碳六烯酸)等。     

盐地碱蓬籽油的提取及特性分析

为了开发和利用盐地碱蓬籽油,用溶剂萃取法从盐地碱蓬籽中提取油脂,然后用GE/MS分析其中的脂肪酸组成及其相对含量,并对盐地碱蓬籽油的碘值、酸值、皂化值等理化指标进行测定,结果表明:盐地碱蓬籽含油量20.12%;盐地碱蓬籽油碘值(Ⅰ)176.4 g/100 g,酸值(KOH)1.84 mg/g,皂化值(KOH)194.6 mg/g;Ak碱蓬籽油检出7种脂肪酸,不饱和脂肪酸占90.65%,其中亚油酸占68.74%,油酸占13.93%,亚麻酸占4.17%.分析结果表明,盐地碱蓬籽油是一种高品质的保健油脂.     

新疆洋葱籽油脂肪酸组成研究

采用气相色谱-质谱联用法(GC/MS)对新疆洋葱籽油中脂肪酸组成及相对含量进行研究.结果表明,新疆洋葱籽油由棕榈酸、亚油酸、油酸等12种脂肪酸组成,不饱和脂肪酸达79.92%,其中油酸为13.11%,亚油酸为65.90%,棕榈酸为10.47%,硬脂酸为4.97%.     

加工鸭蛋蛋黄脂类变化的GC分析

本研究用甲醇和氯仿,使蛋黄液从一相系统转变成二相系统来提取鸭蛋中的脂类,并将脂肪甲基化,用100m×0.25mm的GC毛细管柱来测定脂类中脂肪酸的组成。气相测定结果表明,蛋黄脂肪中C16:0、C18:0、C18:1-11c、C18:2-9c,12c以及C20:3n-3的含量较高;与鲜蛋相比,生和熟的咸蛋在脂肪酸种类上没有明显的变化,但出现了C11:0和C15:0两个饱和脂肪酸。鲜蛋、生熟咸蛋在不饱和脂肪酸含量逐渐减少,分别为67.07%、66.72%、64.68%。表明加工的步骤越多,其蛋黄中的不饱和酸被破坏程度越高。鸭蛋黄通过气相分析发现含有对人体有益的多不饱和脂肪酸如DHA和EPA等。     

Exclusive quantification of methyl-branched fatty acids and minor 18:1-isomers in foodstuff by GC/MS in the SIM mode using 10,11-dichloroundecanoic acid and fatty acid ethyl esters as internal standards

Minor fatty acids (iso- and anteiso-fatty acids, vaccenic acid, elaidic acid) in foodstuff (seafood, milk, and dairy products) were analyzed by gas chromatography with electron ionisation mass spectrometry in the selected ion monitoring mode (GC/EI-MS-SIM). For this purpose, lipids were obtained by accelerated solvent extraction (ASE) and the fatty acid constituents were converted into methyl esters. Instead of the determination of the relative contribution of the minor fatty acids to the sum of all fatty acids detected (the so-called 100% method), we exclusively quantified the minor fatty acids, which was possible by using two types of internal standards (IS-1 and IS-2). For recovery checks during the extraction and/or the transesterification step we added the novel 10,11-dichloroundecanoic acid (DC-11:0) as IS-1. DC-11:0, which has never been detected in foodstuff, was synthesized by electrophilic addition of chlorine to 10-undecenoic acid (11:1n-10). The novel IS eluted in the range of 23:0 from the polar GC column used and showed the same properties as fatty acids in foodstuff during sample preparation. Recovery rate of DC-11:0 was generally >96% in the various samples analyzed. Ethyl esters (FAEE) of a12:0, a14:0, a15:0, a16:0, a17:0, and a18:0 (IS-2) were added to both the external standard (a quantitative mixture of methyl esters of methyl-branched fatty acids and 18:1n-9trans) in order to determine their response factors relative to FAEE and to the food samples. With this technique, (only) methyl-branched fatty acids (MBFAs) as well as vaccenic acid (18:1n-7) and elaidic acid (18:1n-9trans) were quantified in a range of dairy products (including twelve cheeses) and seafood. All samples were analyzed in triplicates, and good standard deviations (concentrations 0.002–5 g/100 g; standard deviations 0.00–0.03) were obtained in all cases. MBFAs were detected in all samples analyzed. The highest content of MBFAs (3.0 g/100 g) was determined in red-smear of romadur cheese. In all except two cheeses, i17:0 was the most abundant MBFA. The highest amount of 18:1n-9trans was found in feta (2.84 g/100 g) whereas 0.03 g/100 g in big eye snapper (Pricanthus tayenus) marked the lowest record of this minor fatty acid. Seal oil contained the highest amount of 18:1n-7 with 5.00 g/100 g, whereas emmental cheese was the sample with the lowest content of this monoenoic fatty acid. The combination of suitable IS and a sensitive GC/EI-MS-SIM method proved to be well suited for the quantification of minor fatty acids in foodstuff. When only a set of fatty acids is going to be analyzed, this method is less time consuming compared to “100% methods” and less prone to false results due to the higher selectivity of GC/MS compared to GC in combination with flame ionisation detection (GC/FID).     

气相色谱/质谱法分析长白山脉松茸中的脂肪酸

建立了长白山脉松茸中脂肪酸的气相色谱/质谱(GC/MS)的测定方法。采用索氏提取法提取松茸中的粗脂肪,经过0.8mol/LKOH-甲醇溶液的甲酯化处理,并运用GC/MS联用技术对其脂肪酸进行了分离分析,同时结合有机质谱学规律,分别对饱和脂肪酸甲酯、单不饱和脂肪酸甲酯、多不饱和脂肪酸甲酯的裂解规律和质谱特征进行了分析归纳。通过质谱数据库检索,鉴定出长白山脉松茸中的9种主要脂肪酸,其中不饱和脂肪酸含量达86.2%,以油酸和亚油酸为主,油酸和亚油酸相对含量分别为34.2%和51.6%。通过对长白山区松茸中脂肪酸的分析,表明松茸是一种良好的保健营养植物,具有很好的开发利用前景。     

Nutritional value and flavor of turbot (Scophthalmus maximus) muscle as affected by cooking methods

In this study, the effects of five cooking methods on nutritional value and flavor of turbot muscle were evaluated. Chemical compositions of samples were determined using AOAC methods, and the fatty-acid composition was determined by gas chromatography–mass spectrometry (GC–MS). Flavors of samples cooked using different methods were characterized by electronic nose. Volatile compounds were determined using solid-phase microextraction (SPME) followed by gas GC–MS. All the samples were investigated before/after cooking. The results showed that the fatty acids found in abundance in the raw sample were C22:6n-3, C16:0, C18:1n-7, and C20:5n-3. All of the fatty acids were detected in steamed samples, while some of the fatty acids were degraded in other cooking methods. Electronic nose can be used to distinguish samples cooked differently. 20, 17, 34, 20, and 23 compounds were detected in samples cooked by frying, baking, microwave heating, boiling in vacuum-sealed bag (BIVSB) and steaming, respectively. Aldehydes, ketones, alcohols, acids, and hydrocarbons were the main volatile components detected. In summary, steaming preserves water, protein, lipids and fatty acids the best in cooked samples while generates desirable flavor, it is recommended as the choice of cooking for turbot.     

莴苣籽油理化性质及脂肪酸组成研究

采用气相色谱-质谱联用法(GC/MS)对莴苣籽油中脂肪酸组成及相对含量进行了分析研究,同时按照国家标准对莴苣籽油的酸值、皂化值、碘值、折光率以及相对密度进行了测定。结果表明:莴苣籽油由亚油酸、油酸、棕榈酸等10种脂肪酸组成,不饱和脂肪酸达75%以上,其中亚油酸53.18%,油酸17.22%,棕榈酸11.58%。研究结果为莴苣籽在食品及药品领域的开发提供了一定理论依据。     

红蘑、猴头菇、香菇三种食用菌中脂肪酸的气相色谱-质谱分析

采用气相色谱-质谱联用方法分别对野生红蘑、猴头菇、香菇三种食用菌中脂肪酸含量与组成进行测定、比较与分析。结果表明:野生红蘑鉴定出3种脂肪酸,其比例为十六酸13.47%,9,12-十八碳二烯酸28.30%,油酸58.23%;猴头菇签定出4种脂肪酸,其比例为十六酸24.03%,9,12-十八碳二烯酸21.85%,油酸42.40%,硬脂酸11.73%;香菇中鉴定出2种脂肪酸,其比例为十六酸11.86%,9,12-十八碳二烯酸88.14%。     

Quantification of Fatty Acid Methyl Esters in Various Biological Matrices by LC-DAD and LC-MS after One-Step Transesterification

The investigation of lipids is a complex field and many analytical methods are applied. Gas chromatography (GC) methods are the standard methods; however, GC systems are not available for every researcher. Hence, an alternative liquid chromatography (LC) method was designed. The LC method was developed and validated for separation of C16:n and C18:n fatty acid methyl esters (FAMEs). Baseline-separation of eight FAMEs was achieved with one C18 column. Two ways of detection (diode array detector, DAD, and mass spectrometry, MS), were established and compared. The validation results proved that the method is precise (RSD?<?10%), accurate (recovery rates 86–120%), and linear (R²?>?0.99) for all analysed FAMEs. Limits of detection (LOD) down to 3 ng and limits of quantification (LOQ) down to 6 ng were achieved. For sample preparation, a one-step transesterification method was used. In bacon fat, duckling lard, and butter, palmitic acid, stearic acid, and oleic acid were the main fatty acids. Olive oil had the highest oleic acid content (60% w/w). Linseed extract showed the highest linolenic acid content (60% w/w). In fungi extract, only a few fatty acids were detected. The highest fatty acid diversity was found in algae extract. Seven of the eight investigated fatty acids were found therein including C16 polyunsaturated fatty acids (PUFAs); further, uncommon C16 and C18 PUFAs were identified. In conclusion, the LC method with DAD detection represents a simple alternative to the usually used GC methods. Using MS detection, unknown compounds can be additionally identified and 10-fold lower LODs can be achieved.     

雪里蕻腌菜特征风味物质的分离和鉴定

运用色-质(GC/MS)联用技术对雪里蕻腌菜的风味物质进行了研究,以期发现能显著影响其风味特性的关键性成分.首先,对雪里蕻腌菜卤汁的乙醚萃取浓缩液组分进行了鉴定,结果发现有机酸组分8个,醇类组分4个,腈类组分2个,酯类组分1个,芳香烃2个.经动态顶空吸附雪里蕻腌菜挥发性组分并进行组分离,在GC-MS图谱上进行组分的分离鉴定,其特征风味在碱性组分中嗅感强烈.雪里蕻腌菜挥发性成分经GC-MS检测解析为烃类、醇类、酯类、腈及杂环化合物,其中丁烯腈及苯并噻唑与雪里蕻腌菜特征风味形成密切相关.     

三种洋葱籽脂肪酸成分的对比研究

采用索氏提取法提取洋葱籽油脂肪酸,提取出的脂肪酸经甲酯化处理后用GC/MS法分析和鉴定其组成。三种洋葱籽油中共分离鉴定出23种脂肪酸,主要成分均为亚油酸、油酸和十六烷酸等,其中不饱和脂肪酸占总量的81.35%(白皮)、82.8%(红皮)和78.94%(黄皮)。结果表明,洋葱籽中不饱和脂肪酸含量丰富,且亚油酸含量很高,将其开发成为药食两用功能性调味品,当具有良好应用前景。     

Comparative Thermal Characteristics and Fatty Acid Composition of Mono- and Diacylglycerols of Lard and Some Commercial Emulsifiers

A study was carried out to compare the fatty acid composition and thermal profiles of mono- and diacylglycerols of six commercial emulsifiers, coded as E1, E2, E3, E4, E5, and E6, purchased from different manufacturers with those of the same derived from lard. The lipid extraction from the commercial emulsifiers was done using the Soxhlet method and the isolation of individual mono- and diacylglycerols was carried out using a column chromatographic method. The isolated partial acylglycerols of lard and individual emulsifiers were subjected to fatty acid analysis by gas chromatography and thermal analysis by differential scanning calorimetry. A clear distinction between lard-based emulsifier and the commercial emulsifiers was achieved by the application of principal components analysis to the fatty acid data. According to thermal analysis, mono- and diacylglycerols of lard displayed significant differences from those of commercial mono- and diacylglycerols with respect to the thermal transitions in the cooling curves. This study concluded that partial acylglycerols of none of the commercial emulsifiers employed in this study displayed similarity to those of lard-based emulsifiers.