Total lipids content and fatty acid composition of seed oils from six pomegranate cultivars

The fatty acid composition of the seed oils of six pomegranate (Punica granatum L) cultivars was qualitatively and quantitatively determined by gas chromatography. The seeds contained oil in the range 51-152 mg kg^?1 dry matter. Intervarietal differences in fatty acid composition were demonstrated (fatty acid esters as % (w/w) total fatty acid esters. Sour varieties had the highest while sour-sweet varieties had the lowest oil content. Eleven fatty acids were identified. In all varieties, the predominant fatty acids were linoleic (25.2-38.6%) and oleic acid (24.8-35.5%) followed by palmitic (18.2-22.6%), stearic (6.9-10.4%) and linolenic acid (0.6-9.9%). To a lesser extent arachidic (1.1-3.4%) and palmitoleic acid (0.2-2.7%) were also found in all varieties. Lauric, myristic, behenic and lignoceric acids were rarely detected. As far as we know linolenic (18:3), arachidic (20:0), behenic (22:0) or lignoceric (24:0) acids have not been previously reported in the seed oils of edible pomegranate varieties. Lignoceric acid has not previously been found in pomegranate seed oil.     

微波辅助甲酯化-快速GC法测定烟草中的多元酸和高级脂肪酸

建立了同时检测烟草中多元酸(草酸、丙二酸、反丁烯二酸、琥珀酸、苹果酸和柠檬酸)和高级脂肪酸(棕榈酸、硬脂酸和亚油酸)的微波辅助甲酯化-快速气相色谱(GC)分析方法,并测定了烤烟及雪茄烟各10个烟叶样品中的多元酸和高级脂肪酸含量(质量分数)。结果表明:①最优前处理条件为衍生化试剂10%硫酸-甲醇溶液,微波功率以20 W/s的速率升高至1200 W(保持1 min),萃取剂二氯甲烷。②快速GC分析时间为8.81 min,目标化合物标准曲线线性良好(r2>0.99),加标回收率在83.18%~114.17%之间,精密度(RSD)小于5%。③烤烟烟叶和雪茄烟烟叶中有机酸含量差异较大,其中烤烟烟叶中多元酸(除苹果酸外)含量低于雪茄烟烟叶,高级脂肪酸(除硬脂酸外)含量高于雪茄烟烟叶。该方法快速、准确,适用于测定烟草中的多元酸和高级脂肪酸含量。      

RP-HPLC法测定东北地区6 种红树莓果实中有机酸组成

建立一种反相高效液相色谱法分离和测定6 种红树莓果实中草酸、酒石酸、柠檬酸、DL-苹果酸和乳酸5 种有机酸的方法。色谱条件为：采用SinoChrom DS-BP C18色谱柱（150 mm×4.6 mm,5 μm）,流动相为甲醇-0.01 mol/L KH2PO4溶液（pH 2.60,97∶3,V/V）,流速0.6 mL/min,柱温30 ℃,检测波长210 nm。结果表明：在此条件下5 种有机酸都被有效地分离,各种有机酸的质量浓度与峰面积在测定范围内呈良好的线性关系,标准曲线相关系数在0.999 3～0.999 9之间;精密度实验相对标准偏差在0.20%～1.53%（n=5）范围内;回收率为98.83%～105.42%,相对标准偏差为0.06%～1.00%。测得6 种红树莓果实中有机酸以柠檬酸为主,含量为1 058.41～1 825.45 mg/100 g,草酸、乳酸、DL-苹果酸含量较低,未检测到酒石酸。该方法简单、高效、准确、重复性好,可用于红树莓果实中有机酸的分离测定。     

大豆中生物物质的分离与分析的研究（Ⅱ）──紫外分光光度法测定大豆中总皂苷

本文用紫外分光光度法测定大豆粉中的总皂苷。样品经脱脂、甲醇提取、正丁醇萃取分离后，在２８０ｎｍ处测定硫酸水解物的吸光度。实验表明，本法的回收率为９５～９９％。四次测定结果的相对标准偏差为６．６％。     

Densitometric determination of carbohydrates: Application to purification and molecular weight determination of polysaccharide from Hericium erinaceum mushroom

A simple, precise, sensitive and quick densitometric method for quantitative total carbohydrate determination as well as for preparation of elution profiles of polysaccharides was developed and validated. The method is based on spotting 3 μL of sample solution by use of disposable micro capillary pipettes as a single drop on a TLC silica gel plate. The plate is then submitted to in situ derivatization with orcinol–sulfuric acid reagent and is scanned densitometrically at 560 nm (for hexoses, deoxy sugars, and uronic acids) or at 610 nm (for pentoses and ketoses). It was demonstrated that the densitometric method has a greater linearity range and similar precision in comparison to the widely used colorimetric phenol–sulfuric acid method. The proposed method was successfully applied to elution profile preparation during purification and molecular weight determination of a novel polysaccharide isolated from the mycelium of edible and medicinal mushroom Hericium erinaceum.     

苯酚-硫酸法与蒽酮-硫酸法测定绿茶茶多糖的比较研究

对苯酚-硫酸法和蒽酮-硫酸法在茶多糖测定中的差异进行比较,并对苯酚-硫酸法的检测条件进行优化,在单因素试验的基础上,选定苯酚质量分数、硫酸用量、显色时间3 个因素,利用响应面试验考察各因素变化对吸光度的影响。通过优化得到最佳测定条件为4.8%苯酚溶液1 mL、浓硫酸5 mL、显色时间29 min、检测波长488 nm。在此条件下的标准曲线在0～0.2 mg/mL范围内呈良好线性关系。该方法对3 种样品的加标回收率均不小于97.55%,重复性实验相对标准偏差为1.82%,说明此方法准确可靠、稳定性高,适合于茶多糖的测定。     

离子排斥色谱-双检测器法同时测定果蔬中的糖、有机酸和维生素C

本文建立了离子排斥色谱-双检测器同时测定农产品中糖类、有机酸和维生素C含量的快速分析方法。选用离子排斥色谱串联DAD和RID双检测器法,以菠菜和西红柿为试样,0.05%硫酸溶液为提取剂,均质提取2 min,同时测定农产品中糖类、有机酸和维生素C含量。对比了不同提取剂、不同提取方式的提取效果,探究了流动相中不同硫酸浓度对有机酸分离效果的影响。结果表明:均质提取法是最为简单高效的提取方法;离子排斥色谱法精密度高(RSD 0.62~1.63%),重复性好(变异系数0.77~8.54%),回收率在87.8-109.8%,测定结果优于国标法。     

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。     

Kinetics of Hydrolyses of Sorghum Molasses with Dilute Mineral Acids and Oxalic Acid and Melibiose with Oxalic Acid

Investigations were carried out on the kinetics of hydrolyses of sorghum molasses with dilute mineral acids and oxalic acid and melibiose with oxalic acid at relatively high temperatures. Kinetic equations for hydrolysis of sorghum molasses and melibiose have been derived from the experimentally determined hydrolysis rate constants as functions of the acid concentration and temperature. It has been shown that the hydrolysis activity of oxalic acid is weaker than those of hydrochloric and sulfuric acid, and that the second hydrogen atom in oxalic acid does not significantly participate in hydrolysis.     

云南产6种蜂蜜中35种游离氨基酸的测定

目的采用全自动氨基酸分析仪测定蜂蜜中35种游离氨基酸的含量。方法蜂蜜样品经水溶解,采用全自动氨基酸分析仪进行定量检测。检测器为荧光检测器,脯氨酸在波长440 nm处测定,其余34种氨基酸在570 nm波长下测定。结果蜂蜜中含有丰富的游离氨基酸成分,且氨基酸组成及含量存在较大区别。脯氨酸是蜂蜜中的主要氨基酸,其平均含量为0.042978 g/100g,占氨基酸组分总含量的71.21%。35种游离氨基酸的线性相关系数均达到0.99以上,回收率在92.4%~109.4%范围内。结论该方法快速、准确,可用于蜂蜜中游离氨基酸含量的测定。     

蜂蜜中17种水解氨基酸的测定

目的采用酸水解法和全自动氨基酸分析仪同时测定蜂蜜中17种氨基酸的含量。方法 8种不同蜜源的蜂蜜经酸水解后,采用全自动氨基酸分析仪进行定量检测;检测器为荧光检测器,脯氨酸在波长440 nm处测定,其余16种氨基酸在570 nm波长下测定。结果 17种氨基酸的线性回归系数均达到0.99以上;方法检出限为5~10 nmoL/L,样品平均回收率为92.1%~99.3%,相对标准偏差RSD小于8.5%。经检测实际样品发现,蜂蜜中不含胱氨酸,氨基酸总量在32.214~78.439 mg/100 g范围。结论该方法快速、准确,可适用于蜂蜜中水解氨基酸含量的测定。     

Pressurized acidified water extraction of black carrot [<Emphasis Type="Italic">Daucus carota</Emphasis> ssp. <Emphasis Type="Italic">sativus</Emphasis> var. <Emphasis Type="Italic">atrorubens</Emphasis> Alef.] anthocyanins

The anthocyanins present in black carrot were extracted with pressurized water acidified with sulfuric, citric and lactic acids. Anthocyanin degradation became significant above 100 °C and there was no improvement when extraction pressure was increased to 100 bar. Therefore, the extraction from black carrot was carried out at temperatures 50, 75 and 100 °C under 50 bar pressure. The extraction efficiencies in terms of acylated and non-acylated anthocyanins were comparable for all three acids used to acidify water at 50 °C, while similar results were observed at 75 °C for both citric and lactic acids. Water acidified with lactic acid showed significantly higher extraction efficiency at 100 °C compared to water acidified with sulfuric and citric acids. Highest degree of polymerization together with increasing degree of browning was observed within extracts when sulfuric acid was used. On the other hand, when organic acids were used to acidify water, a higher extraction efficiency of anthocyanins, accompanied with a relatively low polymerization and browning was observed, with lactic acid giving the best results.     

不同品种葡萄籽油脂肪酸含量的测定

建立同时测定37种脂肪酸的气相色谱-质谱(GC-MS)法,并对吐鲁番产区的40个品种的葡萄籽油中脂肪酸组成及含量进行检测分析。结果表明：葡萄籽油中可检测出19种脂肪酸,40个品种葡萄籽油样中,有14个品种的脂肪酸总含量在90 g/100g以上。沈农金皇后总脂肪酸含量最高,为99.75 g/100g。灰比诺、赤霞珠、沈农金皇后、巨玫瑰等品种可作为富含脂肪酸的葡萄籽油提取的优势品种,其中灰比诺中亚油酸含量最高,赤霞珠其次。对不同品种葡萄籽油进行聚类分析,可被明显分为两类,亚油酸和油酸对于品种间的分类具有较大贡献。本法具有操作简单,灵敏度高,定性定量准确等特点,为葡萄籽油中脂肪酸成分的监测和评估提供了技术支持。     

Rapid simultaneous determination of organic acids,free amino acids,and lactose in cheese by capillary electrophoresis

A capillary electrophoresis (CE) method for the simultaneous separation of 11 metabolically important organic acids (oxalic, formic, citric, succinic, orotic, uric, acetic, pyruvic, propionic, lactic, and butyric), 10 amino acids (Asp, Glu, Tyr, Gly, Ala, Ser, Leu, Phe, Lys, and Trp), and lactose has been optimized, validated, and tested in dairy products. Repeatability and linearity were calculated for each compound, with detection limit values as low as 0.2 x 10(-2) mM for citric acid and Gly. The method was applied to analyze yogurt and different varieties of commercial cheeses. This method yielded specific CE patterns for different varieties of cheese. Also, it has been shown to be sensitive enough to measure small changes in composition of some of those compounds in fresh cheese stored under accelerated ripening conditions for 2 d at 32 degrees C (e.g., from 1728.3 +/- 45.0 to 1166.7 +/- 4.5 mg/100 g of DM in the case of lactose, or from 23.5 +/- 0.6 to 76.8 +/- 16.7 mg/100 g of DM in the case of acetic acid).     

深海鱼油中脂肪酸的柱前衍生-高效液相色谱串联质谱分析

用1-2-(对甲苯磺酸酯)乙基-2-苯基咪唑4,5-f9,10-菲(TSEPIP)作为柱前荧光衍生试剂,在EclipseXDB-C8(4.6×150mm,5μm,Agilent)反相色谱柱上,采用梯度洗脱在检测波长为380nm(激发波长为260nm)的条件下,实现了阿拉斯加深海鱼油中饱和脂肪酸含量的外标法定量测定。26种饱和脂肪酸的线性范围是200.0pmol～48.83fmol,线性相关系数均大于0.9996,检测限为3.824～47.13fmol(信噪比为3:1测得,S/N3:1)。经柱后串联质谱大气压化学电离源(APCI)正离子模式实现了各种饱和与不饱和脂肪酸衍生物的质谱鉴定,进而通过峰面积归一化法得出了所有饱和与不饱和脂肪酸的相对含量。结果表明,深海鱼油主要含有C12～C22的脂肪酸,共鉴定出25种脂肪酸,其中不饱和脂肪酸含量占69.71%(峰面积百分比,下同),特别是具有重要生理作用的多不饱和脂肪酸,如C20:5:5,8,11,14,17-二十碳五烯酸(5,8,11,14,17-eicosapentaenoicacid,EPA,16.62%),C22:6:2,5,8,11,14,17-二十二碳六烯酸(2,5,8,11,14,17-docosahexenoicacid,DHA,12.31%)。     

Development of a cleanup method for polybrominated diphenyl ether (PBDE) in fish by freezing-lipid filtration

A new cleanup method for the determination of brominated flame retardants with an emphasis on polybrominated diphenyl ethers (PBDEs) has been developed for fish tissue sample. This method effectively reduces the sample pretreatment time, labor and required less solvent quantities relative to conventional methods. Freezing-lipid filtration procedure removes approximately 90 % of the lipids in the extract without any significant loss of the PBDEs. A multilayered silica gel column was used for further cleanup of the extracts after freezing-lipid filtration. Multilayered silica gel column chromatography eliminated most of the co-extracted interferences, such as residual lipids and fatty acids. The extracts were analyzed after cleanup by high-resolution gas chromatography/high-resolution mass spectrometry using the isotope dilution method. Tissue samples with 1.6–8.0 and 8.0–40 ppb of PBDE were analyzed using both the sulfuric acid treatment and freezing-lipid filtration cleanup methods in order to evaluate the method performance. Sulfuric acid treatment did not detect 2,4-DiBDE, whereas freezing-lipid filtration detected 2,4-DiBDE but at 50 % recovery. To compare the method, WMF-01 was analyzed via both the sulfuric acid treatment and freezing-lipid filtration cleanup.     

Distribution of fatty acids in triacylglycerols and phospholipids from peas (Pisum sativum L.)

BACKGROUND: The fatty acid distribution of triacylglycerols (TAG) and major phospholipids (PL) obtained from four varieties of peas (Pisum sativum) was investigated. The total lipids extracted from the peas were separated by thin layer chromatography into seven fractions. RESULTS: The major lipid components were PL (52.2–61.3%) and TAG (31.2–40.3%), while hydrocarbons, steryl esters, free fatty acids and diacylglycerols (sn‐1,3 and sn‐1,2) were also present in minor proportions (5.6–9.2%). The main PL components isolated from the four varieties were phosphatidylcholine (42.3–49.2%), phosphatidylinositol (23.3–25.2%) and phosphatidylethanolamine (17.7–20.5%). Significant differences (P < 0.05) in fatty acid distribution were found for different pea varieties. Phosphatidylinositol was unique in that it had the highest saturated fatty acid content among the three PL. However, the principal characteristics of the fatty acid distribution in the TAG and three PL were evident among the four varieties: unsaturated fatty acids were predominantly located in the sn‐2 position while saturated fatty acids primarily occupied the sn‐1 or sn‐3 position in the oils of the peas. CONCLUSION: These results should be useful to both producers and consumers for the manufacture of pea foods in Japan. Copyright © 2007 Society of Chemical Industry     

Assessment and profiling of the fatty acids in two ackee fruit (Blighia sapida Köenig) varieties during different ripening stages

BACKGROUND: The ripening of fruits is characterized by physical, chemical and biochemical compositional changes such as color, sugars and phenolic compounds. Ackee fruit is famous in Jamaica and the Caribbean. This study aimed to assess the variation of fatty acids in two varieties (cheese and butter) ackee (Blighia sapida) fruits during five different ripening stages. RESULTS: The total fatty acid content of ackee fruit was much higher in arils and ranged from 283.4 to 465.1 g kg^?1 dry weight (DW), while in husk they ranged from 235.2 to 465.1 g kg^?1 DW in both varieties. Total fatty acid content declined in the arils and the husks as the fruit ripened. Five major fatty acids were found: palmitic acid (C16:0) and stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic acid (C18:3). In the arils, oleic acid was found at the highest concentration, followed by palmitic, stearic, linoleic and last linolenic acid. The unsaturated:saturated ratio of fatty acids varied from 1.23 to 3.26 in the arils of both varieties, and from 1.03 to 5.05 in the husk. Monounsaturated:polyunsaturated fatty acids ranged from 8.56 to 25.19 in the arils and from 0.62 to 2.33 in the husk. CONCLUSION: The results show that ackee arils contain much higher levels of fats than the husk and the major fatty acid in the arils was oleic acid (Δ9‐cis‐oleic acid, an omega n‐9), while in the husk unsaturated fatty acids were higher than the saturated ones. Oleic acid was the major fatty acid in both varieties, and aril fatty acid content was 10–20 times higher than in the husk. In both varieties, unsaturated fatty acids were relatively higher than saturated ones; however, total fatty acids showed a decline with ripening for arils and husk tissues. © 2012 Society of Chemical Industry     

亚临界水温度对梭子蟹下脚料萃取物性质的影响

目的:为探究亚临界水对梭子蟹下脚料的萃取效果,考察了亚临界水温度对萃取物性质的影响。方法:利用140、170、200、230℃等不同温度的亚临界水提取梭子蟹下脚料萃取物(SCWE),采用凯氏定氮法、苯酚硫酸法和高效液相色谱法等对SCWE的性质进行分析。结果:当亚临界水温度从140℃上升至230℃,SCWE中的总糖和灰分含量分别从1.86%和9.23%下降至0.27%和6.35%,分子量分布为180~1000 u的组分占比从11.09%增加至74.88%,而蛋白含量却出现先上升后下降的趋势。氨基酸分析结果表明,140℃和170℃亚临界水下获得的SCWE氨基酸组成与蟹肉相比没有明显的差别,但进一步提高亚临界水温度,SCWE中的天门冬氨酸、丝氨酸、苏氨酸和精氨酸等氨基酸含量却出现下降趋势。而且,随着亚临界水温度的提高,必需氨基酸和非必需氨基酸的含量均出现先上升后下降的趋势,且在200℃时达到最高值。不管亚临界水的温度是多少,SCWE中的赖氨酸含量都比WHO/FAO模式高。根据蛋白溶解性的结果,发现140℃下提取的SCWE中蛋白存在等电点,而170℃提取的SCWE蛋白溶解度在任一pH下都比其他SCWE高。结论:利用170℃亚临界水萃取梭子蟹加工下脚料获得的SCWE氨基酸不会受到破坏,且蛋白溶解性最高。     

红茶菌发酵罗城毛葡萄13种有机酸的同时检测

为解决目前尚无对红茶菌发酵液中多种有机酸同时检测方法的问题,本文利用液相色谱建立红茶菌发酵液13种有机酸的准确定量方法,并对发酵过程中的典型有机酸变化进行跟踪。优化后的色谱条件:Atlanis T3色谱柱,流动相为0.02 mol/L KH₂PO₄(pH=2.6),流速0.4 mL/min,等度洗脱,柱温30 ℃、检测波长210 nm。此色谱条件下,葡萄糖醛酸和草酸完全重合(只能用葡萄糖醛酸标准曲线相对定量),但其它11种有机酸均能有效分离。定量方法线性范围较宽,R2>0.990,定量限0.080~4.789 mg/L,加标回收率92.68%~107.35%,相对标准偏差<5%,葡萄糖酸、乙酸、苹果酸在发酵过程中一直增加,而其它酸类呈先升后降趋势。葡萄糖酸、乙酸是主要的有机酸,在17 d的发酵液中所测有机酸占75.03%和10.46%。本研究建立的有机酸检测方法适合红茶菌发酵样品的检测,为红茶菌发酵毛葡萄生产酸性功能软饮品提供了基础依据。