• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    七種植物籽油中脂肪酸成分的比較分析

    2012-12-22 09:01:16曾映旭趙晨曦王小梅吳天泉劉琳琪梁逸曾
    關(guān)鍵詞:天泉科學(xué)系化工學(xué)院

    曾映旭,趙晨曦,王小梅,吳天泉,劉琳琪,梁逸曾

    1長沙學(xué)院生物工程與環(huán)境科學(xué)系,長沙410003;2中南大學(xué)化學(xué)化工學(xué)院,長沙410083

    Introduction

    China is a large country in vegetable oil consumption.Soybean,rapeseed,peanut,sesame seed,and cottonseed are main resources of edible vegetable oil in China.But at present,nearly 60%of the total vegetable oil consumption needs to be imported because of the shortage of the above-mentioned resources.Thus,seeking new vegetable oil resources is a hotspot in the edible vegetable oil market of China as well as the whole world[1,2].

    Grape seed(Vitis vinifera L.)is a worldwide well known oil seed crop containing 8%-15%oil.Matthaus stated that the production of oil from grape seeds could result in interesting edible oils with a comparable health benefit as olive oil.Grape seed oil is an extensive and important alternative edible oil resource with essential fatty acids.Therefore it is recognized that it's intake may be beneficial to prevent heart and circulato-ry problems[3].While the main interest in grape seed oil lies in its high content of unsaturated fatty acids such as linoleic acid and α-linolenic acid[4].For example,linoleic acid is the precursor of certain substances of physiological regulation.It can reduce blood cholesterol concentrations and the risk of many cardiovascular and cerebrovascular diseases(CCD),such as coronary artery disease,atherosclerosis,cerebral thrombosis,miocardial infarction,etc.α-Linolenic acid is the precursor of docosahexaenoic acid(DHA)and eicosapentaenoic acid(EPA).Likewise,it can lower bloodlipid and blood pressure,inhibit platelet aggregation,and reduce thrombosis.As is well known,linoleic acid,α-linolenic acid,and arachidonic acid are three essential fatty acids that cannot be synthesized in the body.They can only be ingested from food.These fatty acids are of prime importance for health,and a number of abnormalities in polyunsaturated fatty acid(PUFA)profiles due to malnutrition or diseases have been reported[5].From the nutritional and therapeutic point of view,the content of fatty acids(FAs)in grape seed oil is a key factor for their quality evaluation because of their important roles as metabolites and intermediates in biological processes[6-8].

    Apart from grape seed oil,it was reported that some other vegetable seed oils such as sorghum[9],pumpkin seed[10,11],and sunflower seed[12]with essential fatty acids can also be used as alternative edible oil resources.In fact,vegetable seeds with essential fatty acids are so many more than these.For example,barbary wolfberry fruit seed,passion flower seed,and yangtao kiwifruit seed widely exist.Extraction and percentage composition analysis of the these three seed oils shows that they are promising alternative edible oil resources[13-18].However,as to our knowledge,there is few report on the absolute amount analysis of their fatty acids so far.

    The main objective of the present work is to develop a qualitative and quantitative method for the analysis of essential fatty acids in vegetable oil in order to seek new edible oil resources.This was done by comparative analysis of their fatty acids using supercritical carbon dioxide(SC-CO2)extraction and derivatization gas chromatography mass spectrometry(GC-MS)method.

    Experimental

    Samples and reagents

    Plant seed samples analyzed in this study were provided by Guangdong Academy of Agricultural Sciences,including grape(Vitis vinifera L.)seed,spine grape (Vitis davidii Foex.)seed,foreign grape(Vitis vinifera L.)seed,barbary wolfberry fruit(Lycium barbarum L.)seed,passion flower(Passiflora incarnata L.) seed,pumpkin(Cucurbita pepo L.)seed and yangtao kiwifruit(Actinidia chinensis Planch.)seed.They were identified by Professor Yang Guoping,who is working in The Third Hospital of Xiangya Medical College of Central South University,where the specimens were deposited.

    All the plant seeds were crushed by a portable high speed grinder(Wenling LinDa Machinery Co.Ltd.,Zhejiang,China)before extracting.The free fatty acid standards(palmitic acid,stearic acid,oleic acid,linoleic acid and α-linolenic acid,99+%)and the internal standard(heptadecanoic acid,99+%)were purchased from Sigma(St.Louis,MO,USA).HPLC grade methanol was from Hanbang Science and Technology Corporation(Jiangsu,P.R.China).Sulphuric acid and n-hexane were both supplied by Damao Chemical Reagent Factory(Tianjin,P.R.China).All other chemicals were of analytical reagent grade.Double-distilled water was deionized using Auto-double evaporator of Shensheng Science and Technology Corporation (Shanghai,P.R.China).

    Supercritical carbon dioxide(SC-CO2)extraction Plant seed oil extraction was conducted in a HA231-50-06 semi-batch flow extraction apparatus produced by Nantong Hua’an Supercritical carbon dioxide extraction Corporation(Jiangsu,P.R.China).The extraction capacity was 1000 mL and a maximum flow rate of CO2was 50 Kg/h.The SC-CO2extraction conditions were as follows:extraction pressure:30 MPa,separation temperature:45℃,extraction time:70 min.In all experiments,100 g samples of powdered seeds were placed in the extractor cylinder,and filter mesh screens were placed at both ends of the cylinder to prevent any carry over of particles.The cylinder was placed into the temperature-controlled chamber,and great care was taken to ensure that the air can purge through the filter before the extraction.The SC-CO2was pumped at a constant flow rate and directed to the bottom of the extractor forup-flow configuration.The supercritical phase from the extractor was passed through the valves,into which the pressure was throttled gradually and serially via two separators.The oil was collected every 15 min from the two separators and the CO2was cooled and recycled into the system.Successive collected samples were weighed and treated.

    Derivatization of Sample

    Direct transesterification of FAs is recommonded in FA analysis[19].In the present work,a direct derivatization method,which can esterify both the lipid-bound and free fatty acids(FFAs),was developed mainly based on the literature[20]with minor revision.The derivatization approach is as follows:Equal volumes(10 μL)of heptadecanoic acid(C17∶0)internal standard(3 mg/ mL in n-hexane;stored at–40℃)was added to 0.5 μL of each sample.After that,2.0 mL of 1%H2SO4-CH3OH was added,vortex-mixed for 30 s and reacted at 80℃ water bath for 60 min.Then,the lipids were extracted with 2.0 mL of n-hexane twice using a vortex mixer for 30 s.Samples containing the fatty acid methyl esters were blown to dryness under nitrogen,dissolved in 1.0 mL of n-hexane,and stored at 4℃ away from light until GC analysis.

    Gas chromatography mass spectrometry

    Analyses were carried out in a Hewlett-Packard 6890 gas chromatograph fitted with a DB-23 capillary column (30 m×0.25 mm i.d.,film thickness 0.25 μm),interfaced with an Hewlett-Packard mass selective detector 5973N(Agilent Technologies,USA)operated by HP Enhanced ChemStation software,G1701DA MSD ChemStation Rev.D.00.00.38.Oven temperature program:80℃ to 175℃,at 25℃/min,then programmed to 220℃,at 4℃/min,and held for 5 min at 220℃; injector temperature:250℃;carrier gas:helium,adjusted to a column velocity of flow 1.0 mL/min,splitting ratio 20∶1,interface temperature:250℃,standard electronic impact(EI)MS source temperature:230℃; MS quadrupole temperature:150℃,mass scan range: 30-500 units,scan velocity:3.12 scans/s.The identification of fatty acid methyl esters(FAMEs)was carried out by searching in NIST 02 mass database as well as the mass spectrum and retention time of authentic compound.

    Validation of the analytical method

    The standard stock solutions of fatty acids(palmitic acid,stearic acid,oleic acid,linoleic acid,and α-linolenic acid)and internal standard stock solution of heptadecanoic acid(C17∶0)were prepared in n-hexane.The working solutions were obtained by further dilution with n-hexane.All solutions were stored at 4℃ away from light before analysis.Accuracy was assessed using standard addition method at three different(low,median and high)concentration levels of standard compounds by replicate measurements(n=6).In order to determine the accuracy of the method,Sample 7 was spiked with a known amount of the five standard fatty acid compounds,processed under the proposed transesterification process and analyzed using the specified GC-MS method.The recovery rates were obtained by the ratios of the found contents to the sum of original and added contents.

    The analytical precision(each,n=6)were evaluated by analysis of all the samples at different times during the same day.The concentration of each sample was determined using calibration standards prepared on the same day.

    Results and Discussion

    Optimization of the derivatization procedure and GC-MS analysis

    The derivatization procedure of fatty acids was determined mainly based on the literature[20].But three factors such as derivatization temperature,derivatization time,and the amount of derivatization reagent were optimized by single factor test to obtain higher precision.Yangtao kiwifruit seed oil(Sample 7)is taken as an example to illustrate the derivatization condition optimization result obtained.Fig.1 shows the concentration of fatty acid methyl esters(FAMEs)obtained at different derivatization time(10,20,30,60,90 min),tempera-ture(40,60,80,100℃)and amount of derivatization reagent(0.5,1.0,2.0,3.0mL).

    Fig.1 The derivatization profiles for fatty acids in Sample 7

    From Fig.1,one can find that the concentration of FAMEs were usually increased with the increase of derivatization time,temperature and amount of derivatization reagent.But that of α-linolenic acid methy ester was decreased obviously when the derivatization time last longer than 60 min or the derivatization temperature was higher than 80℃.This may because of the decomposition of α-linolenic acid methy ester[21].Thus the optimum derivatization time,temperature and amount of derivatization reagent can be determined to be 60 min,80℃ and 2 mL,respectively.And all the subsequent experiments were carried out using 2 mL H2SO4-CH3OH(1%,v/v)solution at 80℃ for 60 min.

    Fig.2 GC-MS profiles of Sample using different columns

    To improve the separation of the FAMEs,three capillary columns(HP-5,F(xiàn)FAP and DB-23)were employed and Sample 7 was also taken as an example to illustrate the process.Fig.2 shows the separation results in the three cases,from which it is shown that when a DB-23 column was used,the best resolution was obtained within a few minutes(Fig.2(c)).Therefore,DB-23 column was selected for the GC-MS analysis of the FAMEs of plant seed oils.

    Method validation

    The regression equations,correlation coefficients(R),linear ranges and limits of detection(LOD)of the five fatty acids were listed in Table 1.Good linear relationships(R=0.9997 to 0.9999)between peak areas and the concentrations,wide linear ranges and low LODs were exhibited.The recoveries(in%)of the five fatty acids from Sample 7 were detected by standard addition method at low,median and high concentrations.The recovery percents were in the ranges of 91.4% to 98.4%as listed in Table 2.These values were within the limits of acceptable variability for the analyte concentration of these kinds of samples.

    Table 2 Recoveries of fatty acids determined by standard addition method(n=6)

    Fig.3 GC-MS profiles of the seven seed oils

    Identification and content comparative analysis of fatty acids in plant seed oils

    The seven different plant seed oils described above were analyzed by the proposed method.The chromatograms of the FAMEs profiles obtained are shown in Fig.3.The major fatty acids were identified by comparison of their mass spectra with NIST02 mass database through G1701DA mass spectrum ChemStation and as well as by comparison of their mass spectra and retention times with those of the injecting authentic components at the same conditions.The five common peaks in the seven plant seed oils were identified to be palmitic (C16∶0),stearic(C18∶0),oleic(C18∶1),linoleic (C18∶2)and α-linolenic(C18∶3)acid.They are essential fatty acids for health.The relative amounts of unsaturated fatty acids(UFAs)and saturated fatty acids(SFAs)in the plant seed oils were presented on the basis of free fatty acids according to peak area normalization method(Table 3).From Table 3,it can be seen that,the total relative amounts of UFAs and SFAs were in the ranges of 53.9%to 74.1%and 11.1%to 23.0%,respectively.The distribution of fatty acid composition was quite similar except yangtao kiwifruit seed oiL.Yangtao kiwifruit seed oil has a high percentage of α-linolenic acid(43.7%)and a low content of linoleic acid(10.1%)as well as adequate content of oleic acid(14.2%),palmitic acid(7.4%),and stearic acid(3.3%).Meanwhile,α-linolenic acid was not detected in other samples except passion flower seed (0.5%)and pumpkin seed(0.6%)with extremely low percentages of α-linolenic acid.As for Samples 1 to 6,linoleic acid was shown to be the most important component ranged from 34.2%to 58%,followed by oleic acid(11.5%-21.8%)and palmitic acid(7.4%-17.2%),though some minor difference exists between the percentages of the major fatty acids from each other.

    Table 3 Fatty acid identified and their relative amount of different seed oils

    To evaluate their quality,the comparsion of absolute content of fatty acids in different plant seed oils seems more reasonable and important.Thus our developed quantitation method was used to determine the contents of the fatty acids in the seven different plant seed oils quantitatively.Table 4 shows the summary results obtained by using the calibration curve of each investigated compound.From Table 4,it is found that the differences of contents of palmitic acid,stearic acid,and oleic acid among the seven samples were not obvious.But the contents of linoleic acid ranged from 75 to 628 milligram per milliliter of oil,the maximum difference was about 8 times.The highest content of linoleic acid was detected in the passion flower seed oil(Sample 5).While α-linolenic acid was not detected from Samples 1 to 4 and its content in Samples 5 and 6 was actually very low.The highest content of α-linolenic acid was observed in the yangtao kiwifruit seed(Sample 7),in which the content of α-linolenic acid(0.294 g/mL) was much higher than linoleic acid(75 mg/mL).The relative standard deviations(RSDs)listed in Table 4 were less than 5.0%except for that(5.8%)of α-linolenic acid in Sample 6 because of its low content.

    Table 4 Contents of fatty acids in the seven seed oils

    Conclusion

    This is the first research on the fatty acid compositions of barbary wolfberry fruit seed oil,passion flower seed oil,and yangtao kiwifruit seed oil,which provides an important and useful scientific basis for new edible oil resource exploitation.

    (1)A derivative gas chromatography mass spectrome-try method was developed for fatty acid analysis in plant seed oil after optimizing of derivative and chromatographic conditions.The method was validated to be precise and reliable with low detecting limit and wide linear range having high correlation coefficients ranging from 0.9997 to 0.9999 of palmitic,stearic,oleic,linoleic acid,and α-linolenic acid.

    (2)Seven different plant seed oils including spine grape seed,grape seed,foreign grape seed,pumpkin seed,barbary wolfberry fruit seed,passion flower seed,and yangtao kiwifruit seed oils were analyzed.Their total relative amounts of unsatured fatty acids and saturated fatty acids were in the ranges of 53.9% to 74.1%and 11.1%to 23.0%,respectively.The contents of palmitic,stearic,oleic,and linoleic acid in the first six samples ranged from 0.114 to 0.285 g/mL,0.110 to 0.198 g/mL,0.150 to 0.263 g/mL,and 0.251 to 0.628 g/mL,respectively.

    (3)The first six plant seed oils can be used to be alternative sources of edible oil due to the presence of all saturated and unsaturated fatty acids required for human health.Being different from the others,yangtao kiwifruit seed oil has high content of α-linolenic acid (0.294 g/mL)and relative low content of linoleic acid (0.075 g/mL)and certain saturated fatty acids,it may be much better alternative source of edible and nutritional oil because α-linolenic acid and linoleic acid are two main functional constituents.

    Acknowledgement This work was supported by National Natural Science Foundation of China (81173533)and scientific Research Fand of Hunan Prorincial Education Department(11A017).The authors are grateful to Professor Yang Guoping from The Third Hospital of Xiangya Medical College of Central South University for the plant seed samples

    1 Cao Y,Suo YR.Extraction of Microula sikkimensis seed oil and simultaneous analysis of saturated and unsaturated fatty acids by fluorescence detection with reversed-phase HPLC.J Food Compos Anal,2010,23:100-106.

    2 Orhan I,Deliorman OD,Ozeclik B.Antiviral activity and cytotoxicity of the lipophilic extracts of various edible plants and their fatty acids.Food Chem,2009,115:701-705.

    3 Pardo JE,F(xiàn)ernandez E,Rubio M,et al.Characterization of grape seed oil from different grape varieties(Vitis vinifera).Eur J Lipid Sci Technol,2009,111:188-193.

    4 Silva TLD,Bernardo E,Nobre B,et al.Extraction of Victoria and red globe grape seed oils using supercritical carbon dioxide with and without ethanoL.J Food Lipids,2008,15:356-369.

    5 Holman RT.Control of polyunsaturated acids in tissue lipids.J Am Coll Nutr,1986,5:183-211.

    6 Tranchida P,Donato P,Dugo P,et al.Comprehensive chromatographic methods for the analysis of lipids.Trends Anal Chem,2007,26:191-205.

    7 Basconcillo LS,Mccarry BE.Comparison of three GC/MS methodologies for the analysis of fatty acids in Sinorhizobium meliloti:Development of a micro-scale,one-vial method.J Chromatogr B,2008,871:22-31.

    8 Isbell TA,Mund MS,Evangelista RL,et al.Method for analysis of fatty acid distribution and oil content on a single Lesquerella fendleri seed.Indus Crops Prod,2008,28:231-236.

    9 Mehmood S,Orhan I,Ahsan Z,et al.Fatty acid composition of seed oil of different Sorghum bicolor varieties.Food Chem,2008,109:855-859.

    10 Applequist WL,Avula B,Schaneberg BT,et al.Comparative fatty acid content of seeds of four Cucurbita species grown in a common(shared)garden.J Food Compos Anal,2006,19: 606-611.

    11 Fruhwirth GO,Hermetter A.Production technology and characteristics of Styrian pumpkin seed oil.Eur J Lipid Sci Technol,2008,110:637-644.

    12 Kanya TCS,Rao LJ,Sastry MCS.Characterization of wax esters,free fatty alcohols and free fatty acids of crude wax from sunflower seed oil refineries.Food Chem,2007,101:1552-1557.

    13 Pan TA,Liu DH,Mao ZY,et al.Studies on the extraction of oil from wolfberry seeds with supercritical CO2.J Ningxia Univ,Nat Sci,2000,21(2):156-158.

    14 Chen QX,Wu NY,Gao JP,et al.Extraction of Lycium seed oil and analysis of its composition,China Oils Fats,2000,25 (2):53-55.

    15 Ouyang JW,Xiong XY,Wang HX,et.al.Oil extract from passionflower seed by supercriticai CO2and it’s composition analysis.Acta Horticul Sin,2007,34:239-241.

    16 Liu SC,Zhang CH,Deng CJ,et al.Extraction of Passiflora seed oil by supercritical carbon dioxide and analysis of its properties.Chem Indus Forest Prod,2008,28(6):70-74.

    17 Wang XG,Wang HR,Hu XJExtraction and analysis of Actinidia chinesis seed oil.China Oils Fats,2004,29(5):58-60.

    18 Zhang YS,Zhao YW.Comparison of four extraction methods on Chinese gooseberry seed oil yield.J Chin Cereals Oils Assoc,2007,22:76-78

    19 Susana PA,Cabrita ARJ,Antonio JMF,et al.Improved method for fatty acid analysis in herbage based on direct transesterification followed by solid-phase extraction.J Chromatogr A,2008,1209:212-219.

    20 Mulder C,Schouten JA,Poppsnijders C.Determination of free fatty acids:A comparative study of the enzymatic versus the gas chromatographic and the colorimetric method.J Clin Chem Clin Biochem,1983,21:823-827.

    21 Juarez M,Polvillo O,Conto M,et al.Comparison of four extraction/methylation analytical methods to measure fatty acid composition by gas chromatography in meat.J Chromatogr A,2008,1190:327-332.

    猜你喜歡
    天泉科學(xué)系化工學(xué)院
    使固態(tài)化學(xué)反應(yīng)100%完成的方法
    國家開放大學(xué)石油和化工學(xué)院學(xué)習(xí)中心列表
    看大別山彩虹瀑布
    致力草學(xué),推進(jìn)草業(yè),共創(chuàng)輝煌
    ——慶祝湖南農(nóng)業(yè)大學(xué)草業(yè)科學(xué)系建系20 周年
    作物研究(2021年2期)2021-04-26 09:34:40
    【鏈接】國家開放大學(xué)石油和化工學(xué)院學(xué)習(xí)中心(第四批)名單
    醉美天泉 詩意棲居
    華人時刊(2021年21期)2021-03-09 05:31:22
    江蘇省盱眙縣:紅杉映天泉
    江蘇省淮安市:小雪節(jié)氣杉林紅
    樂在其中 研我自由——記清華大學(xué)數(shù)學(xué)科學(xué)系助理教授宗正宇
    《化工學(xué)報》贊助單位
    免费看不卡的av| 天天操日日干夜夜撸| 久久久久久久久久久久大奶| 国产男人的电影天堂91| 人妻人人澡人人爽人人| 亚洲美女搞黄在线观看| 春色校园在线视频观看| 最新的欧美精品一区二区| 在线观看免费日韩欧美大片 | 亚洲欧美日韩卡通动漫| 国产精品久久久久久精品古装| 男人添女人高潮全过程视频| 免费观看av网站的网址| 一本—道久久a久久精品蜜桃钙片| 国产免费视频播放在线视频| 蜜桃久久精品国产亚洲av| 不卡视频在线观看欧美| 日本午夜av视频| 亚洲情色 制服丝袜| av不卡在线播放| 亚洲av在线观看美女高潮| 在线精品无人区一区二区三| 国产 一区精品| 国产高清国产精品国产三级| 亚洲成人一二三区av| 在线播放无遮挡| 日韩av在线免费看完整版不卡| 2018国产大陆天天弄谢| 久久久久精品性色| 少妇的逼水好多| 欧美精品一区二区大全| 丰满乱子伦码专区| 国产亚洲一区二区精品| 成年人免费黄色播放视频 | 曰老女人黄片| 精品一区二区三卡| 午夜福利网站1000一区二区三区| 国产精品人妻久久久影院| 午夜老司机福利剧场| 高清在线视频一区二区三区| 天堂中文最新版在线下载| 99久久中文字幕三级久久日本| 亚洲成人手机| 91成人精品电影| 黑丝袜美女国产一区| 26uuu在线亚洲综合色| 免费观看性生交大片5| 国产无遮挡羞羞视频在线观看| 国产伦理片在线播放av一区| 免费高清在线观看视频在线观看| 啦啦啦中文免费视频观看日本| 99热全是精品| 国产在线视频一区二区| 日本wwww免费看| 国产成人a∨麻豆精品| 成年av动漫网址| 岛国毛片在线播放| 女人精品久久久久毛片| 亚洲国产色片| 亚洲国产精品999| 免费人妻精品一区二区三区视频| 国产黄片视频在线免费观看| 亚洲av在线观看美女高潮| 久久国产精品大桥未久av | 国产欧美日韩精品一区二区| a级毛片在线看网站| √禁漫天堂资源中文www| 曰老女人黄片| 国产成人一区二区在线| 日韩不卡一区二区三区视频在线| 夜夜骑夜夜射夜夜干| 精品亚洲成国产av| 日本-黄色视频高清免费观看| 爱豆传媒免费全集在线观看| 51国产日韩欧美| 亚洲人成网站在线观看播放| 欧美日韩在线观看h| 人人妻人人添人人爽欧美一区卜| 纯流量卡能插随身wifi吗| 国产精品一区二区三区四区免费观看| 色吧在线观看| 少妇人妻精品综合一区二区| 人妻一区二区av| 国产一区二区三区av在线| 欧美日韩视频高清一区二区三区二| 欧美3d第一页| 久久久久久久久久人人人人人人| 国产成人精品婷婷| 国产精品一二三区在线看| 欧美人与善性xxx| 少妇被粗大猛烈的视频| 婷婷色综合www| 夜夜爽夜夜爽视频| 国产永久视频网站| 天美传媒精品一区二区| 乱码一卡2卡4卡精品| 夜夜看夜夜爽夜夜摸| xxx大片免费视频| 麻豆成人午夜福利视频| 国产午夜精品一二区理论片| 精品久久久久久久久亚洲| 一二三四中文在线观看免费高清| 少妇精品久久久久久久| 久久久午夜欧美精品| 国产综合精华液| 欧美 日韩 精品 国产| 性高湖久久久久久久久免费观看| 777米奇影视久久| 国产精品久久久久久精品电影小说| 日韩欧美一区视频在线观看 | 少妇猛男粗大的猛烈进出视频| 99热这里只有精品一区| 在线看a的网站| 久久久国产一区二区| 国产黄色视频一区二区在线观看| 国产在线视频一区二区| 女人精品久久久久毛片| 久久久久国产精品人妻一区二区| 免费大片黄手机在线观看| 亚洲美女视频黄频| 春色校园在线视频观看| av专区在线播放| 日本与韩国留学比较| 国产av国产精品国产| 国产在线一区二区三区精| 中文字幕人妻丝袜制服| 亚洲国产精品一区三区| av在线app专区| 日本黄大片高清| 欧美另类一区| 亚洲美女搞黄在线观看| 日韩av不卡免费在线播放| 成人漫画全彩无遮挡| 丝袜在线中文字幕| 精品熟女少妇av免费看| 天美传媒精品一区二区| 黄色欧美视频在线观看| 精品久久久久久久久亚洲| 久久午夜福利片| 亚洲精品国产av成人精品| 韩国高清视频一区二区三区| 99久久人妻综合| 在线观看免费视频网站a站| 国产欧美亚洲国产| 亚洲伊人久久精品综合| 多毛熟女@视频| 国产在视频线精品| 99热这里只有是精品在线观看| 黑人巨大精品欧美一区二区蜜桃 | videossex国产| 大又大粗又爽又黄少妇毛片口| 婷婷色麻豆天堂久久| av国产精品久久久久影院| 中文字幕人妻熟人妻熟丝袜美| 国产成人精品无人区| 男女国产视频网站| 熟妇人妻不卡中文字幕| 国产免费福利视频在线观看| 久久青草综合色| 91成人精品电影| 亚洲激情五月婷婷啪啪| 最后的刺客免费高清国语| 99久久精品一区二区三区| 街头女战士在线观看网站| 国产精品久久久久久av不卡| 成人午夜精彩视频在线观看| 亚洲国产av新网站| 日韩一区二区三区影片| 全区人妻精品视频| 精品午夜福利在线看| 久久人人爽人人片av| av有码第一页| 精品午夜福利在线看| 国产亚洲一区二区精品| 国产免费福利视频在线观看| 天美传媒精品一区二区| 久久这里有精品视频免费| 午夜av观看不卡| 成人无遮挡网站| 午夜视频国产福利| 99久久中文字幕三级久久日本| 一级黄片播放器| 久久久久久久久久久免费av| 青春草亚洲视频在线观看| 亚洲精品国产av蜜桃| 你懂的网址亚洲精品在线观看| 91久久精品国产一区二区三区| 久久久久久久国产电影| 日产精品乱码卡一卡2卡三| 亚洲成人手机| 在线精品无人区一区二区三| 最近2019中文字幕mv第一页| 麻豆成人av视频| 最黄视频免费看| 国产精品熟女久久久久浪| 欧美激情国产日韩精品一区| 国产精品免费大片| 亚洲人成网站在线播| 国产成人精品无人区| 久久99热这里只频精品6学生| 91成人精品电影| 自拍偷自拍亚洲精品老妇| 王馨瑶露胸无遮挡在线观看| 久久亚洲国产成人精品v| 日本vs欧美在线观看视频 | 少妇丰满av| 国产淫片久久久久久久久| 免费看光身美女| 自拍欧美九色日韩亚洲蝌蚪91 | 七月丁香在线播放| 晚上一个人看的免费电影| 我的老师免费观看完整版| 一区二区三区四区激情视频| 欧美老熟妇乱子伦牲交| 中文精品一卡2卡3卡4更新| 超碰97精品在线观看| 免费观看在线日韩| 热re99久久国产66热| 人妻 亚洲 视频| 免费播放大片免费观看视频在线观看| 丰满饥渴人妻一区二区三| 国产熟女欧美一区二区| 日日爽夜夜爽网站| 麻豆成人av视频| av又黄又爽大尺度在线免费看| 久久精品久久久久久久性| 午夜福利在线观看免费完整高清在| 观看美女的网站| 欧美97在线视频| 国产一区二区在线观看日韩| 人妻系列 视频| 人体艺术视频欧美日本| 久久 成人 亚洲| 青春草视频在线免费观看| 久久精品国产自在天天线| 简卡轻食公司| 亚洲第一区二区三区不卡| 久久精品久久精品一区二区三区| 免费看不卡的av| 免费不卡的大黄色大毛片视频在线观看| 建设人人有责人人尽责人人享有的| 日本免费在线观看一区| 美女内射精品一级片tv| 日本黄色日本黄色录像| 久久午夜综合久久蜜桃| 日韩精品免费视频一区二区三区 | 黑丝袜美女国产一区| 9色porny在线观看| 赤兔流量卡办理| 成人国产av品久久久| 成年女人在线观看亚洲视频| 国产精品国产三级国产av玫瑰| 亚洲成人一二三区av| 纵有疾风起免费观看全集完整版| 午夜91福利影院| 人妻一区二区av| 欧美精品国产亚洲| 精品人妻一区二区三区麻豆| 最黄视频免费看| 免费黄色在线免费观看| 伊人亚洲综合成人网| 丰满少妇做爰视频| 久久久国产精品麻豆| 噜噜噜噜噜久久久久久91| 亚洲国产毛片av蜜桃av| 极品人妻少妇av视频| 丰满饥渴人妻一区二区三| 人妻夜夜爽99麻豆av| 观看美女的网站| h视频一区二区三区| 亚洲怡红院男人天堂| 99热这里只有是精品在线观看| 男女免费视频国产| 亚洲欧美清纯卡通| 免费av不卡在线播放| 成人漫画全彩无遮挡| 美女中出高潮动态图| 国产一区二区在线观看av| 欧美3d第一页| av播播在线观看一区| a 毛片基地| 久久久久久久久久人人人人人人| 国产精品久久久久久av不卡| 精品酒店卫生间| 久久久久久久亚洲中文字幕| 色网站视频免费| 国产精品国产三级国产av玫瑰| 人妻人人澡人人爽人人| tube8黄色片| 肉色欧美久久久久久久蜜桃| 极品人妻少妇av视频| 人妻人人澡人人爽人人| av黄色大香蕉| 九九在线视频观看精品| 亚州av有码| 成年人午夜在线观看视频| 中文字幕人妻熟人妻熟丝袜美| 99视频精品全部免费 在线| 亚洲av福利一区| 狂野欧美激情性bbbbbb| 亚洲精华国产精华液的使用体验| 国产精品成人在线| 美女福利国产在线| 国产伦在线观看视频一区| 日韩av免费高清视频| 老女人水多毛片| 国产一区二区三区av在线| 午夜激情福利司机影院| 伊人亚洲综合成人网| 国内精品宾馆在线| 精品熟女少妇av免费看| 大香蕉97超碰在线| 肉色欧美久久久久久久蜜桃| 高清欧美精品videossex| 亚洲成色77777| 国产在线男女| 视频区图区小说| 丝袜在线中文字幕| 美女主播在线视频| 三上悠亚av全集在线观看 | 亚洲精品一区蜜桃| 精品一区二区免费观看| 精品亚洲乱码少妇综合久久| 国产一区二区在线观看av| 欧美日韩亚洲高清精品| 亚洲天堂av无毛| 麻豆乱淫一区二区| 日本与韩国留学比较| 免费黄色在线免费观看| a级毛片在线看网站| 男人爽女人下面视频在线观看| 久久国产精品大桥未久av | 欧美精品一区二区大全| 黄色视频在线播放观看不卡| 22中文网久久字幕| 国产美女午夜福利| 婷婷色麻豆天堂久久| 国产精品99久久99久久久不卡 | 九色成人免费人妻av| 丝袜喷水一区| 国产精品人妻久久久影院| 新久久久久国产一级毛片| 99久久精品热视频| 亚洲精品一区蜜桃| 色吧在线观看| 欧美一级a爱片免费观看看| 各种免费的搞黄视频| 中文字幕人妻熟人妻熟丝袜美| 九九久久精品国产亚洲av麻豆| 国产欧美日韩一区二区三区在线 | 黄色毛片三级朝国网站 | av不卡在线播放| 中文字幕人妻丝袜制服| 老司机亚洲免费影院| 全区人妻精品视频| 五月天丁香电影| 天堂中文最新版在线下载| 国产在视频线精品| 午夜福利在线观看免费完整高清在| 夜夜骑夜夜射夜夜干| 国产精品久久久久久久电影| 午夜福利影视在线免费观看| 国产免费福利视频在线观看| 国产 精品1| 天天操日日干夜夜撸| 一本一本综合久久| 永久免费av网站大全| 亚洲av免费高清在线观看| 国产精品久久久久久久电影| 国内精品宾馆在线| 在线观看av片永久免费下载| 日韩一区二区三区影片| 国产黄色免费在线视频| 免费黄色在线免费观看| 欧美精品一区二区免费开放| 免费看日本二区| 91aial.com中文字幕在线观看| 99热6这里只有精品| 亚洲精品乱码久久久久久按摩| 国产成人aa在线观看| 日韩人妻高清精品专区| 午夜激情福利司机影院| av播播在线观看一区| 国产精品久久久久久精品古装| 亚洲熟女精品中文字幕| 狠狠精品人妻久久久久久综合| 日韩中字成人| 精品99又大又爽又粗少妇毛片| 五月伊人婷婷丁香| 乱人伦中国视频| 最黄视频免费看| 久久久久久人妻| 99久久精品热视频| 日本91视频免费播放| 精品一区二区免费观看| 亚洲第一av免费看| 成人特级av手机在线观看| 亚洲欧美成人精品一区二区| 人人妻人人添人人爽欧美一区卜| 成人免费观看视频高清| 中文字幕精品免费在线观看视频 | 久久亚洲国产成人精品v| 人人澡人人妻人| 99re6热这里在线精品视频| 黄色怎么调成土黄色| 黄色一级大片看看| 在线观看免费高清a一片| 久久久久久久久久人人人人人人| 国产精品熟女久久久久浪| 亚洲国产精品一区二区三区在线| 最近2019中文字幕mv第一页| 亚洲美女黄色视频免费看| 亚洲成人一二三区av| av福利片在线| 久久精品国产鲁丝片午夜精品| 国产成人免费观看mmmm| 午夜影院在线不卡| 精品一区在线观看国产| 亚洲,欧美,日韩| 中文字幕av电影在线播放| 免费大片黄手机在线观看| 国产成人免费无遮挡视频| 亚洲成人av在线免费| 亚洲va在线va天堂va国产| 午夜福利在线观看免费完整高清在| 曰老女人黄片| 国产午夜精品久久久久久一区二区三区| 晚上一个人看的免费电影| 精品久久久久久电影网| 黄色欧美视频在线观看| 久久影院123| 免费大片黄手机在线观看| 王馨瑶露胸无遮挡在线观看| 我的老师免费观看完整版| 97精品久久久久久久久久精品| 亚洲精品久久久久久婷婷小说| 久久99热6这里只有精品| 69精品国产乱码久久久| 91成人精品电影| 一边亲一边摸免费视频| 亚洲无线观看免费| 国产av国产精品国产| 最近中文字幕2019免费版| 在线 av 中文字幕| 国产精品国产三级专区第一集| 一级av片app| 如日韩欧美国产精品一区二区三区 | 中国国产av一级| 久久精品国产亚洲av涩爱| 99久久综合免费| 欧美日韩一区二区视频在线观看视频在线| 深夜a级毛片| 人人妻人人添人人爽欧美一区卜| 久久国产精品男人的天堂亚洲 | 精华霜和精华液先用哪个| 国产乱人偷精品视频| 亚洲av福利一区| 蜜桃在线观看..| 免费观看性生交大片5| 成人亚洲欧美一区二区av| 成年人午夜在线观看视频| 蜜臀久久99精品久久宅男| 亚洲av不卡在线观看| 美女国产视频在线观看| 日韩欧美一区视频在线观看 | 大陆偷拍与自拍| 在现免费观看毛片| 只有这里有精品99| 亚洲av在线观看美女高潮| 欧美精品国产亚洲| 欧美激情国产日韩精品一区| 99九九在线精品视频 | 香蕉精品网在线| 精品久久久久久电影网| 日韩一区二区视频免费看| 久久人人爽av亚洲精品天堂| 国产精品一区二区在线观看99| 男人和女人高潮做爰伦理| 亚洲精品乱码久久久久久按摩| 极品教师在线视频| 日韩大片免费观看网站| 在线播放无遮挡| 亚洲成人手机| 22中文网久久字幕| 亚洲国产成人一精品久久久| xxx大片免费视频| 国产伦理片在线播放av一区| 大片免费播放器 马上看| 边亲边吃奶的免费视频| 如何舔出高潮| 日韩三级伦理在线观看| 人妻一区二区av| av国产久精品久网站免费入址| 欧美精品人与动牲交sv欧美| 如何舔出高潮| 在线观看三级黄色| 亚洲性久久影院| 王馨瑶露胸无遮挡在线观看| 久久久亚洲精品成人影院| 亚洲精品456在线播放app| 桃花免费在线播放| 国产精品不卡视频一区二区| 18禁在线无遮挡免费观看视频| 纵有疾风起免费观看全集完整版| 久热久热在线精品观看| 777米奇影视久久| 欧美人与善性xxx| 日韩免费高清中文字幕av| 男女啪啪激烈高潮av片| 免费黄网站久久成人精品| xxx大片免费视频| 在线精品无人区一区二区三| 99久久精品国产国产毛片| 只有这里有精品99| 精品亚洲成国产av| 18禁在线播放成人免费| 高清午夜精品一区二区三区| 免费在线观看成人毛片| 久久久久久伊人网av| 久久久欧美国产精品| 久久国产亚洲av麻豆专区| 天天操日日干夜夜撸| 亚洲国产成人一精品久久久| 日韩av免费高清视频| 欧美日本中文国产一区发布| 成年人午夜在线观看视频| 69精品国产乱码久久久| 男女无遮挡免费网站观看| 91在线精品国自产拍蜜月| 亚洲欧美一区二区三区黑人 | 一本色道久久久久久精品综合| 日韩成人伦理影院| 夜夜骑夜夜射夜夜干| 国产精品成人在线| 国产精品麻豆人妻色哟哟久久| 久久久精品94久久精品| 黄色日韩在线| 免费黄色在线免费观看| 日本vs欧美在线观看视频 | 王馨瑶露胸无遮挡在线观看| 亚洲精品日韩在线中文字幕| 精品亚洲乱码少妇综合久久| 在线观看国产h片| 国产av码专区亚洲av| 久久99热6这里只有精品| 国产精品国产三级国产av玫瑰| 人人妻人人爽人人添夜夜欢视频 | 久久女婷五月综合色啪小说| 亚洲精品第二区| 久久久久久久久大av| 亚洲伊人久久精品综合| 久久久a久久爽久久v久久| 最新的欧美精品一区二区| 一级毛片久久久久久久久女| 国产伦理片在线播放av一区| 亚洲色图综合在线观看| 免费观看在线日韩| 韩国av在线不卡| 免费播放大片免费观看视频在线观看| videos熟女内射| 九色成人免费人妻av| 国产精品99久久久久久久久| 国产精品久久久久久av不卡| 午夜福利网站1000一区二区三区| 在线免费观看不下载黄p国产| 亚洲精品,欧美精品| 蜜桃久久精品国产亚洲av| av免费在线看不卡| 午夜免费观看性视频| 18禁在线播放成人免费| 久久久久久久久久久免费av| 色婷婷久久久亚洲欧美| 纵有疾风起免费观看全集完整版| 天堂俺去俺来也www色官网| 少妇丰满av| 日本欧美视频一区| 国产精品女同一区二区软件| 亚洲av二区三区四区| 色婷婷久久久亚洲欧美| av播播在线观看一区| 国产精品蜜桃在线观看| 日本vs欧美在线观看视频 | 午夜av观看不卡| 特大巨黑吊av在线直播| 久久久久久伊人网av| 日韩精品免费视频一区二区三区 | 免费看光身美女| 亚洲高清免费不卡视频| 免费观看av网站的网址| 三级国产精品片| 又大又黄又爽视频免费| 又黄又爽又刺激的免费视频.| 国产欧美另类精品又又久久亚洲欧美| 欧美变态另类bdsm刘玥| 人人澡人人妻人| 波野结衣二区三区在线| 亚洲精品国产av成人精品| 亚洲精品视频女| 国产深夜福利视频在线观看| 国产成人精品婷婷| 国产成人精品一,二区| av免费观看日本| 老熟女久久久| 自拍欧美九色日韩亚洲蝌蚪91 | 精品久久国产蜜桃| 欧美+日韩+精品| 国产免费一区二区三区四区乱码| 欧美xxⅹ黑人| 99热全是精品| 免费播放大片免费观看视频在线观看| 在线观看人妻少妇| 伦理电影免费视频| 人妻制服诱惑在线中文字幕| 午夜福利影视在线免费观看| 男女啪啪激烈高潮av片|