HS-SPME-GC-MS技术分析不同加工阶段的甲鱼腥味成分变化

为研究不同加工方式对甲鱼腥味成分的影响,采用HS-SPME-GC-MS技术对甲鱼预煮、卤制、烘烤不同加工阶段的腥味物质进行分析。结果表明,经NIST/Willey质谱数据库检索和文献对照,新鲜甲鱼共检出48种挥发成分,确定36种成分,包括烃类21种、醛类12种、醇类化合物5种、芳香类5种、羧酸类3种、酮类1种、酯类1种。其中以己醛的百分含量最多,为29.1%,有青草味;庚醛占10.69%,具有强烈的油脂氧化味;壬醛占12.58%,提供鱼腥味;占2.02%的对二甲苯有刺激味;占2.36%的1-辛烯-3-醇具有土腥味。认为己醛、壬醛、庚醛、1-辛烯-3-醇等共同形成了甲鱼的腥味。通过预煮、卤制、烘烤等加工工艺后,腥味成分已减少至只能检测出己醛和壬醛,且含量都不超过1%。表明经预煮、卤制、烘烤等加工可以有效控制甲鱼的腥味。

宰后不同冷藏时间对牛胃肌肉风味特征的影响

为了研究宰后牛胃肌肉挥发性风味物质的变化以及不同冷藏时间对牛胃肌肉风味的影响,以肉牛瘤胃和皱胃为试验材料,对不同冷藏时间点(0、3、5 d)的挥发性风味物质进行研究。采用气相色谱-质谱(gas chromatography-mass spectrometer,GC-MS)技术确定了关键挥发性风味物质的变化,并应用模糊综合评价法对瘤胃和皱胃的感官质量进行了评定。结果表明,宰后牛瘤胃检测到挥发性风味物质共78种,皱胃中共69种。其中,1-辛烯-3-醇、异戊醇、1-壬醇、乙酸、正己醛、异戊醛、庚醛、正辛醛、苯甲醛、3-羟基-2-丁酮、二甲基二硫、二甲基三硫、苯并噻唑、2-乙酰基噻唑和2-正戊基呋喃是瘤胃和皱胃中关键的呈香物质,己酸、壬醛、苯酚、吲哚是引起瘤胃和皱胃品质下降的关键风味物质。确定对瘤胃肌肉风味影响最大的时间为3 d,皱胃为0 d;模糊综合评价结果表明,瘤胃感官质量优劣顺序为3 d>0 d>5 d,皱胃感官质量优劣顺序为0 d>3 d>5 d。综合上述实验结果可知,宰后瘤胃肌肉冷藏3 d对风味的影响最大,皱胃冷藏0 d对风味的影响最大。

玉米蛋白粉制备羊肉味风味料的工艺研究及风味成分分析

以玉米蛋白粉酶解液,控制氧化羊脂,D-木糖为主要原料,研究美拉德反应制备羊肉味风味料的最优工艺,并对羊肉味风味料的风味成分及可接受性进行分析。在单因素试验基础上,利用正交试验确定羊脂控制氧化的最优工艺及美拉德反应最佳反应条件;顶空固相微萃取-气相色谱质谱法(headspace solid-phase microextraction-gas chromatography-mass spectrometer,HS-SPME-GC-MS)测定羊肉味风味料的风味成分;模糊综合评价法确定了羊肉味风味料的可接受性。结果表明,羊脂控制氧化最优工艺为反应时间4. 0 h,温度135℃,通气量0. 30m^3/(kg·h);美拉德反应最佳反应条件为温度120℃,初始pH 6. 5,反应时间2 h;羊肉味风味料挥发性成分共检出24种风味物质,其中杂环类9种(88. 93%)、酸类6种(4. 98%)、酮类3种(0. 58%)、醛类2种(0. 61%)、酯类1种(0. 14%)、酚类1种(2. 12%)、胺类1种(0. 36%)(质量分数);模糊矩阵的综合评价结果表明人们对羊肉味风味料的喜欢比例为69%。

GC-O-MS分析赊店酒中的香气成分

为了探究浓香型白酒中的主要呈香物质,采取液液萃取法,用二氯甲烷作为萃取剂提取赊店酒中的挥发性香气化合物,采用气质联用技术(Gas Chromatography-Mass Spectrometer,GC-MS),进行条件优化并通过NIST11谱库检索,共鉴定出45种挥发性物质。用气相色谱-嗅觉测量法(gas chromatography-olfactometry,GC-O)分析共测出18种呈香物质,其中酯类12种,醇类1种,挥发性酸4种,芳香族1种。香气贡献较大的化合物是丁酸乙酯、戊酸乙酯、己酸乙酯、庚酸乙酯、辛酸乙酯、棕榈酸乙酯、乙酸和丁酸。

How to identify “Material basis–Quality markers” more accurately in Chinese herbal medicines from modern chromatography-mass spectrometry data-sets: Opportunities and challenges of chemometric tools

Modern chromatography-mass spectrometer(MS) technology is an essential weapon in the exploration of traditional Chinese medicines(TCMs) which is based on the "effectiveness-material basis-quality markers(Q-markers)". Nevertheless, the hardware bottleneck and irregular operation will limit the accuracy and comprehensiveness of test results. Chemometrics was thereby used to solve the existing problems: 1) The method of ‘design-modeling-optimization’ can be adopted to solve the multi-factor and multi-level problems in sample preparation/parameter setting;2) The approaches of signal processing can be used to calibrate the deviation from retention time(rt) dimension and mass-to-charge ratio(m/z) dimension in different types of instruments;3) The methods of multivariate calibration and multivariate resolution can be utilized to analyze the co-eluting peaks in complex samples. When the researchers need to capture essential information on raw data sets extracting the higher level of information on essential features, 1) The significant components which affects the drug properties/efficacy can be find by the pattern recognition and variable selection;2) Fingerprint-efficacy modeling is explored to clarify the material basis, or to screen out the Q-markers of biological significance;3) Chemometric tools can apply to integrate chemical(metabolic) fingerprints with network pharmacology, bioinformatics, omics and others from a multi-level perspective. Under these programs, the qualitative/quantitative works will achieve in chemical(metabolic) fingerprint and metabolic trajectories, which leads to an accurate reflection of "material basis and Q-markers" in TCMs. Likewise, an in-depth hidden information can be disclosed, so that the components of drug properties/efficacy will be found. More importantly,multidimensional data can be integrated with fingerprints to acquire more hidden information.

Analysis of Fragrance Composition in Three Cultivars of Osmanthus fragrans Albus Group Flower by Gas Chromatography-Mass Spectrometry

With supercritical CO2 fluid extraction（SCFE）, essential oil was extracted from three cultivars of Xianning osmanthus. The fresh osmanthus flower was processed with a petroleum ether digestion method to produce the extractum. The yields of essential oil and extractum were 0.19 % and 0.13 % （m/m） respectively. The essential oil and fragrance composition and content extracted were analyzed with gas chromatography-mass spectrometer （GC-MS）. The result showed that essential oil contained 36.99%（area/total area） of ionone, ionol and 13.11% of linalool; ionone and ionol contained in extractum were as high as up to 33.33%, while linalool up to 21.92%. Whether essential oil or extractum contains only about 40% fat acid and other ester matters. None of environmental estrogen （phthalic ester） was found in fragrance ingredients. The result also showed that the quality of O. fragrans Albus group fragrance in Xianning is better than that produced in Hangzhou and Anhui districts.

黄酒中“焦糖香”特征香气物质葫芦巴内酯的检测及风味贡献研究

采用液液微萃取(liquid-liquid microextraction,LLME)结合气相色谱-质谱联用(gas chromatography-mass spectrometer,GC-MS)技术建立了黄酒中"焦糖香"特征香气物质葫芦巴内酯的快速分析方法。该方法检测限为0.66μg/L,定量限为1.02μg/L,不同类型黄酒中加标回收率在80%~120%之间,当日精密度和隔日精密度相对标准偏差均在10%以内,能够满足黄酒中葫芦巴内酯批量快速检测的需要。采用该方法测定了不同区域24款典型黄酒样品中葫芦巴内酯的含量,结果显示该物质在黄酒中普遍存在,含量在42.05~244.34μg/L之间。首次测定了黄酒基质中葫芦巴内酯的香气阈值(11μg/L),并基于香气活力值(odor activity value,OAV)研究了葫芦巴内酯在黄酒中的风味作用,结果显示所有测定样品中葫芦巴内酯含量均高于其香气阈值,表明该物质对黄酒整体香气具有重要影响。进一步比较分析发现葫芦巴内酯在浙江和上海地区黄酒中含量显著高于其他地区黄酒。

Temperature dependency of VOCs release characteristics of asphalt materials under varying test conditions

Asphalt pavement is increasingly used in paving and roofing.However,the release of volatile organic compounds(VOCs)from asphalt harm both the environment and humans.Various methods were applied to characterize the VOCs for better understanding and inhibiting.However,asphalt VOCs have huge heating temperature dependency,which makes the asphalt VOCs’characterization complicated.In this research,three kinds of heating conditions,thermal gravimetric(TG)analyzer,pyrolysis(PY)analyzer,and thermal desorber(TD),were compared to determine the temperature dependency of VOC release characteristics.Gas chromatography and mass spectrometer(GC-MS)were then coupled for VOC detection.Results indicated that the TG heating condition can surely simulate the volatilization of VOCs from some asphalt that is not in contact with air(no oxygen)during the actual construction process,while PY and TD represent the substances released by the asphalt due to the boiling point at a certain temperature and under the actual construction process,respectively.The components detected by TG heating condition are both large and small molecules,while PY and TD heating condition will detect large molecules or small molecules,respectively.The VOC composition results under various heating conditions reflect the chemical reaction law of asphalt molecules in the heating process.When heating asphalt binders to a higher temperature,macromolecular substances will gradually crack and oxidize into small molecular substances,sulfides and nitrides.With the increase of temperature,the change trend of VOC components under different conditions is different.

Bioavailable curcumin formulations:A review of pharmacokinetic studies in healthy volunteers

Curcumin is a widely studied natural compound which has shown tremendous in vitro therapeutic poten- tial. Despite that, the clinical efficacy of the native curcumin is weak due to its low bioavailability and high metabolism in the gastrointestinal tract. During the last decade, researchers have come up with dif- ferent formulations with a focus on improving the bioavailability of curcumin. As a result, a significant number of bioavailable curcumin-based formulations were introduced with the varying range of enhanced bioavailability. The purpose of this review is to collate the published clinical studies of cur- cumin products with.improved bioavailability over conventional （unformulated） curcumin. Based on the literature search, 11 curcumin formulations with available human bioavailability and pharmacokinet- ics data were included in this review. Further, the data on clinical study design, analytical method, phar- macokinetic parameters and other relevant details of each formulation were extracted. Based on a review of these studies, it is evident that better bioavailability of formulated curcumin products is mostly attrib- uted to improved solubility, stability, and possibly low first-pass metabolism. The review hopes to provide a quick reference guide for anyone looking information on these bioavailable curcumin formulations. Based on the published reports, NovaSol （185）, CurcuWin （136） and LongVida （100） exhibited over 100-fold higher bioavailability relative to reference unformulated curcumin. Suggested mechanisms accounting for improved bioavailability of the formulations and details on the bioanalysis methods are also discussed.

Potential of the White-Rot Fungus Pleurotus pulmonarius F043 for Degradation and Transformation of Fluoranthene

Fluoranthene, a four-ring polycyclic aromatic hydrocarbon that is possible genotoxic in nature, has been used as an indicator for assessing polycyclic aromatic hydrocarbon （PAH）-containing pollutants. Microbial degradation is one of the promising methods in removing up PAH-contaminated environments. White-rot fungi have showed the ability to degrade a wide range of PAHs. This study aimed to investigate enzyme production, fungal biomass, and glucose utilization during the biodegradation process of fiuoranthene by a white-rot fungus Pleurotus pulmonarius F043 and to identify the metabolites produced in the degradation process. The extracellular ligninolytic enzyme system of the fungi, producing laccases and peroxidases, was directly linked to the biodegradation of fiuoranthene. The production of ligninolytic enzymes during fluoranthene degradation was related to an increase in the biomass of Pleurotus pulmonarius F043. Fluoranthene removal decreased with an increase in fluoranthene concentrations. The highest biomass production of Pleurotus pulmonarius F043 （〉 4 400 mg L-1） was found in the 10 mg L-1 fluoranthene culture after 30 d of incubation. Two fluoranthene metabolites, naphthalene-l,8-dicarboxylic acid and phthalic acid, were found in the process of fluoranthene degradation. Laccase was revealed as the major enzyme that played an important role in degradation process. Suitable conditions must be found to promote a successful fungal biotransformation augmentation in liquid culture.

Quantitative determination of the saponin content and GC-MS study of the medicinal plant Cassytha filiformis(linn.)leaves

Objective:To determine the phytochemicals,total saponin content and types of saponin present in leaf extracts of Cassytha filiformis.Methods:The leaves were extracted with n-hexane and methanol.The methanol extract was fractionated.The total saponin content of the butanol fraction was determined by colorimetry via a UV spectrophotometer and ginsenoside was used as the standard.Measurements were carried out at 550 nm.The butanol fraction was subjected to gas chromatography-mass spectrometer analysis.Results:All screened phytochemicals were absent in the n-hexane extract while saponins,steroids,tannins and glycosides were present in the methanol extract.Flavonoids and alkaloids were absent.The total saponin content of the methanol extract is 73.47μg ginsenoside Rb1 equivalent/g extract.The chromatography-mass spectrometer analysis gave eicosanoic acid,methyl ester as the most abundant compound and the steroidal saponin,cholestan-7-one and cyclic 1,2-ethanedienyl acetal as the most abundant saponin in the butanol fraction.Conclusions:The leaves of Cassytha filiformis are rich in steroidal saponins.

Factors controlling the enrichment of natural gas in Kuche depression,Tarim Basin,NW China:Molecular geochemical evidence from sedimentary organic matter

Using molecular geochemical data from infrared spectrometer and pyrolysis gas chromatography-mass spectrometry, this paper investigates the petroleum generation characteristics of Jurassic coal measures from Kuche depression, Tarim Basin, NW China. The results showed that the Jurassic coaly rocks with medium maturity (R0%: 0.8-1.1) were enriched in gas-prone functionalities (-CH3) and low molecular weight pyrolysates (【nC21), indicating that the coaly rocks from Kuche depression were gas/condensate prone at the stages of middle to high maturation, and it was further supported by the oil/source correlation from well Yinan 2 in this region.

GC-MS analysis of leaf extracts of Terminalia macroptera and Dioclea reflexa,two medicinal plants used for the treatment of respiratory tract disorders

Objective:To analyze the phytochemicals that are present in two medicinal plants which are used for the treatment of respiratory tract infections by gas chromatography-mass spectrometer.Methods:The plant leaves were extracted with n-hexane and methanol separately.Both extracts were analyzed for present phytochemicals using the method described by Harborne,1985 while only methanol extracts were subjected to gas chromatography-mass spectrometer analysis.Results:Phytochemical screening of the methanolic extracts of Terminalia macroptera(T.macroptera)revealed the presence of glycosides,tannins,flavonoids,saponins and steroids while that of Dioclea reflexa(D.reflexa)showed the presence of flavonoids,saponins and steroids.The n-hexane extracts were devoid of the screened phytochemicals.Twelve and twenty-five compounds were identified in the leaves of T.macroptera and D.reflexa respectively.These compounds were fatty acids,fatty acid esters,other esters,heterocyclics and phenolics.The most abundant compound in T.macroptera was benzenetriol(53.30%)while the predominant compounds in D.reflexa were dodecanoic acid,methyl ester(15.31%),5,5,8a-trimethyl-3,5,6,7,8,8a-hexahydro-2H-chromene(9.73%),10-octadecenoic acid,methyl ester and 2-hexadecanoic acid,methyl ester(8.95%).Benzofuran,2,3-dihydro,3,7,11,15-tetramethyl-2-hexadecen-1-ol and hexadecanoic acid,methyl ester were common in both plant extracts.The antimicrobial properties of the leaves of these plants could be responsible for their use in the treatment of respiratory tract infections.Conclusions:Some of the identified phytochemicals in the plant leaves are responsible for its use in the treatment of respiratory tract infections.

Bioactive compounds and antifungal activity of three different seaweed species Ulva lactuca,Sargassum tenerrimum and Laurencia obtusa collected from Okha coast,Western India

Objective:To evaluate bioactive compounds responsible for antifungal activity from seaweeds of Okha coast,Western India.Methods:Each species were extracted with different solvents with increasing polarity:hexane,ethyl acetate,chloroform and methanol using Soxhlet apparatus.The antifungal activity was determined by agar diffusion plate method by using fluconazole,ketoconazole and amphotericin B as standards.Gas chromatography-mass spectrometer analysis was done for identification of bioactive compounds present in crude extract.Results:The gas chromatography-mass spectrometer analysis of all the extracts revealed the presence of steroids,fatty acids and esters compounds.Among the three species,the maximum crude extract yield(53.46%)and the largest inhibition zone(36 mm)were recorded in methanol extract of Ulva lactuca,whereas the minimum crude extract yield and inhibition zone were recorded in chloroform extract of the same species as 0.5%and 10 mm,respectively.Methanol and ethyl acetate extract showed the maximum antifungal activity and the major important compounds like steroids,fatty acids and esters were detected with higher amount in all the extracts.Conclusions:The present study revealed that the different seaweed extracts showed moderate to significant antifungal activity against the strains tested as compared with the standard fungicides,and polar solvents methanol and ethyl acetate were comparatively efficient for extraction of different metabolites that are responsible for antifungal activity.

A green synthesis of antimicrobial compounds from marine microalgae Nannochloropsis oculata

Objective:To determine the antibacterial and anti-candidal activities of fatty acid methyl esters(FAME)extracted from marine microalga Nannochloropsis oculata and evaluate the inhibition activity of DNA isolated from test pathogenic microorganism.Methods:FAME was synthesized by transesterification of oil using immobilized lipase and characterized using gas chromatography-mass spectrometer.The FAME profile was determined using gas chromatography.The antimicrobial effect was tested by disc diffusion method against Gram-positive bacteria Staphylococcus aureus,Bacillus subtilis,Gram-negative bacteria Escherichia coli,Pseudomonas aeruginosa and yeast Candida albicans,at varying concentrations of 10,20 and 30μL/disc.Results:The results shown that palmitic acid(C16:0),oleic acid(C18:1)and arachidic acid(C20:0)were dominant in Nannochloropsis oculata oil.The study revealed that FAME was more active against Gram-negative than against Gram-positive and yeast.DNA inhibition activity results also confirmed that FAME had the bactericidal effect that was revealed by sheared fragments of DNA.Conclusions:The results indicated that microalgal FAME could be potentially utilized as a newer and good source of therapeutic agent in pharmaceutical industry.

GC-MS and FT-IR analysis of a coastal medicinal plant-Hyptis suaveolens(L.)Poit

Objective:To investigate the bioactive components of a coastal medicinal plant,Hyptis suaveolens(L.)Poit.(H.suaveolens)leaves using fourier transform-infrared spectroscopy and gas chromatography-mass spectrometer(GC-MS).Methods:The chemical compositions of the ethanol extract of whole plant of H.suaveolens was investigated using PerkinElmer GC-MS,while the mass spectra of the compounds found in the extract was matched with the National Institute of Standard and Technology library.Results:The results of fourier transform-infrared spectroscopy analysis confirmed the presence of secondary alcohols,phenols,alkanes,alkynes,aromatics,nitro compounds and aliphatic compounds.GC-MS analysis of the ethanolic extract revealed the existence of 30 phytochemical compounds.5,5-Dimethylimidazolidin-2,4-diamine(20.35%)was found to be the major compound.Conclusions:The results of this study offer a platform to use H.suaveolens leaves as herbal alternative for various diseases.

GC-MS and NMR analysis of the bioactive compounds from the crude extracts of Waltheria indica and the histopathological changes induced in albino rats challenged with Naja nigricollis venom

Objective:To develop a characteristic fingerprint of the different chemical compounds of plant by gas chromatography-mass spectrometer(GC-MS)and nuclear magnetic resonance(NMR)analysis and assess the effect of the crude extract on histological changes induced in Naja nigricollis(N.nigricollis)envenomed albino rats.Methods:The coarsely powdered Waltheria indica(W.indica)whole plant material was extracted using 70%methanol.GC-MS analysis was carried out using a Shimadzu GC-MS QP 2010 plus system of gas chromatography interfaced to a mass spectrometer.The identification of components was based on National Institute of Standard and Technology-08 and Willey-8 libraries.Hydrogen-NMR spectra of the extracts was performed using Bruker Biospin Avance 400-MHz NMR spectrophotometer with a 5 mm broad inverse probe head,equipped with shielded z-gradient accessories and C-13 NMR hetero-nuclear single quantum correction was carried out using the Brucker’s standard pulse library.The efficacy of the crude extract of W.indica whole plant was tested and the lesions induced in the liver,brain and kidney of albino rats challenged with N.nigricollis were analyzed by light microscopy.Results:The identification of the bioactive compounds from W.indica by GC-MS analysis revealed 41 peaks.A total of 38 compounds were identified with majority having important pharmacological activities that included anti-microbial,anti-cancer,anti-oxidant antiinflammatory,anti-allergenic,anti-ageing,anti-arthritic,larvicidal,anti-convulsant and herbicidal activities.C-13 and hydrogen-NMR analysis of W.indica elucidated key bioactive compounds in the whole plant that were consistent with the classes of bioactive compounds detected by GC-MS analysis.The efficacy of the crude extract of W.indica whole plant in ameliorating histopathological lesions induced in the liver,brain and kidney of albino rats challenged with N.nigricollis venom revealed the abrogation of tissue degeneration when compared with the experimental control group.Conclusions:The present study identified an array of bioactive compounds present in W.indica and reported their ethno-botanical uses in the treatment of a wide range of medical exigencies and showed scientific evidence of the detoxification of N.nigricollis venom by W.indica.