茶叶活性成分分离分析技术的应用

重点介绍超临界流体萃取和色谱(SFE和SFC),高效液相色谱(HPLC),气相色谱-质谱(GC-MS)联用技术,核磁共振(NMR),原子吸收光谱法和毛细管电泳(CE)在茶叶生物活性成份的分离,纯化和结构鉴定等应用领域的研究进展。     

牡丹籽壳中白藜芦醇的分离及结构表征

采用乙酸乙酯萃取牡丹籽壳70%乙醇提取物,获得牡丹籽壳乙酸乙酯部位提取物。采用硅胶色谱柱将其分离,然后采用高效液相色谱(HPLC)、紫外光谱(UV)、红外光谱(IR)和核磁共振谱(NMR)等波谱技术对分离获得的白藜芦醇进行鉴定和结构表征。结果表明:分离所得为较高纯度的白藜芦醇单体,纯度为96.25%。     

基于核磁共振技术对亚麻籽油进行脂肪酸组成检测与品质鉴别

采用核磁共振(NMR)技术对山西省内生产的亚麻籽油进行脂肪酸组成检测及品质鉴别。首先运用气相色谱-质谱联用(GC-MS)法确认纯亚麻籽油和掺杂亚麻籽油脂肪酸组成的差异;然后通过核磁共振谱仪确认差异核磁共振氢谱（1H NMR）和碳谱（13C NMR）的特征峰,以快速判别亚麻籽油是否掺杂;最后,采用1H NMR法计算亚麻籽油中的脂肪酸含量,并与国标GC法进行对比。结果表明：与纯亚麻籽油相比,掺杂亚麻籽油中含有花生一烯酸和芥酸;通过花生一烯酸和芥酸1H NMR和13C NMR特征峰可以定性鉴别亚麻籽油是否掺杂;采用1H NMR法计算的亚麻籽油中亚麻酸含量与GC法一致。说明基于NMR技术对亚麻籽油脂肪酸组成进行检测,可以快速鉴别亚麻籽油品质。     

红发夫酵母中3R,3’R-虾青素的分离纯化和结构鉴定

研究红发夫酵母中3R,3’R-虾青素的分离纯化工艺条件,并利用高效液相色谱串联大气压化学电离源质谱(high performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry,HPLCAPCI-MS)、核磁共振(nuclear magnetic resonance,NMR)和高效液相色谱-紫外光谱(high performance liquid chromatography-ultra violet,HPLC-UV)对纯化得到的虾青素结构进行鉴定。结果表明:利用细胞玻璃研磨器进行研磨提取、硅胶柱层析分离和结晶提纯相结合的方法,能够有效减少反式虾青素的异构化,得到的虾青素纯度高于95%。采用高效液相色谱-质谱仪(high performance liquid chromatography-mass spectrometry,HPLC-MS)、超导核磁共振谱仪(1H和13C NMR)以及Chiralpak IC手性固定化纤维柱分析,显示制备的反式虾青素几乎都以3R,3’R结构组成。     

高速逆流色谱分离制备常春油麻藤豆荚中丁香脂素

采用高速逆流色谱(HSCCC)方法从常春油麻藤豆荚中分离制备丁香脂素。HSCCC的溶剂系统条件为V(甲基叔丁基醚)∶V(甲醇)∶V(水)=2∶1∶1。从5 g粗提物中可一次分离得到纯度89.5%的丁香脂素单体1.28g,进一步重结晶可得到纯度98.1%的丁香脂素。分离得到的丁香脂素结构经电喷雾质谱(ESI-MS)以及核磁共振氢谱(1H NMR)和碳谱(13C NMR)进行鉴定。杭州不同地区的常春油麻藤豆荚中丁香脂素的含量在3.0 g/kg以上,是一种优质的天然丁香脂素资源,通过高速逆流色谱分离制备可获得大量天然丁香脂素。     

野生白木香叶乙酸乙酯提取物化学成分的分离鉴定

为探究沉香茶系列保健食品的主要原料白木香(Aquilaria sinensis)叶片药理活性的物质基础,本研究通过含70%丙酮的水溶液渗漉提取、石油醚和乙酸乙酯多次萃取后,运用硅胶柱色谱、Sephadex LH-20凝胶柱色谱和制备高效液相色谱等技术从野生白木香叶片乙酸乙酯萃取部位中分离纯化得到7个化合物,根据MS、NMR等波谱数据分别鉴定其中6个化合物为麦角甾醇(1)、槲皮素-3-O-β-D-吡喃半乳糖苷(2)、豆甾醇(3)、5,4'-二羟基-7-甲氧基二氢黄酮(4)、谷甾醇(5)、槲皮素-3-O-β-D-吡喃葡萄糖苷(6)。6个化合物按照结构可分为甾醇及其衍生物类(3个),黄酮苷类(2个)和二氢黄酮类(1个)。其中化合物1-2为首次在瑞香科植物中分离得到,化合物4是在瑞香科沉香属植物中首次分离得到的二氢黄酮类化合物,并首次报道了该化合物的2D NMR数据及归属。     

高速逆流色谱分离制备胡椒中的胡椒碱

采用高速逆流色谱(high-speed countercurrent chromatography,HSCCC)法从胡椒中分离制备胡椒碱。HSCCC的溶剂系统条件为正己烷-乙酸乙酯-甲醇-水(1:1:1:1,V/V)。从5g粗提物中可一次分离得到纯度为98.72%的胡椒碱单体1.58g,分离得到的胡椒碱结构经电喷雾质谱以及核磁共振氢谱(1H NMR)和碳谱(13C NMR)进行鉴定。该法制备量大、分离效率高,对胡椒碱在食品医药领域的应用具有重要意义。     

短氟链拒液整理剂的合成与表征

通过氟化的环氧丁烷单体开环聚合反应,合成了一种新的含五氟丙基短氟碳链的低聚合度拒液整理剂PFOX。采用FTIR、~1 H NMR、~(19)F NMR、~(13) C NMR质谱和凝胶渗透色谱对PFOX的化学结构进行了表征,结果表明,目标产物符合设计要求,其数均分子量Mn和重均分子量Mw分别是2 419和2 709,分子量分布d为1.12。PFOX含有活泼的端羟基,可以开发一列环保型的拒水拒油的纺织后整理剂,替代将被禁用的长氟链产品。     

1种水溶性霸王花多糖的分离纯化及结构鉴定

目的:从霸王花中提取分离和纯化多糖,并对其理化性质、光谱学特征和结构特征进行研究。方法:霸王花经水提醇沉、脱蛋白、冷冻干燥得到水溶性粗多糖(hylocereus undatus polysaccharide,HUP),再通过DEAE-Cellulose 52纤维素柱和Sephadex G-100凝胶柱层析分离纯化,得到1种水溶性均一多糖HUP0。对获得的纯化组分采用傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FT-IR)、高效分子排阻色谱、气相色谱-质谱联用和核磁共振波谱(nuclear magnetic resonance,NMR)等方法进行化学结构分析。结果:经纯化后得到均一的霸王花多糖样品HUP0,分子质量为33.24 k D,特性黏度(η)为47.16 m L/g,比旋度为+69°,平均粒径为196.96 nm;FT-IR图谱结果表明HUP0是中性糖且以β-构型为主;结合高效液相色谱、单糖组成、甲基化分析、NMR对HUP0的结构进行鉴定分析后,表明HUP0为(1→4)-β-D-半乳聚糖。     

一种蛹虫草多糖的结构特征及体外抗氧化活性

采用分子筛层析法从人工培养蛹虫草子实体中分离纯化得到一种多糖W-CBP80Ⅰ,进而分别采用凝胶渗透色谱(GPC)、气-质联用(GC-MS)、红外光谱(IR)、核磁共振(~1H NMR和~(13)C NMR)研究其理化性质和结构特征。结果表明:W-CBP80Ⅰ含有α-糖苷键,并主要由甘露糖、半乳糖和葡萄糖组成。它主要成分为低分子量多糖,分子量为8.93×10~3。此外,W-CBP80Ⅰ具有体外清除DPPH,羟基和超氧阴离子自由基活性。     

面絮粒度分布对面条品质影响研究

以13种小麦为原料,将面絮按粒度分级,对不同粒度的面絮分布与籽粒、小麦粉、面条品质进行相关性分析,探索采用面絮评价小麦粉制作面条品质的适应性。结果表明,小颗粒面絮(d1.5 mm)含量与籽粒水分呈显著或极显著负相关,大颗粒面絮(d1.5 mm)含量与其呈显著或极显著正相关;小颗粒面絮含量与面筋指数呈显著正相关,大颗粒面絮含量与其呈显著负相关;小颗粒面絮含量与面条质构参数呈显著或极显著正相关,大颗粒面絮含量与其呈显著或极显著负相关;小颗粒面絮含量与面条感官评价得分呈显著或极显著正相关,大颗粒面絮含量与其呈极显著负相关。综合结果表明:采用面絮评价小麦粉制作面条品质具有可行性,小颗粒面絮含量多,有利于提高面条品质;大颗粒面絮含量多,不利于提高面条品质。     

Comparison of different digesta collection methods to determine the apparent digestibilities of the nutrients at the terminal ileum in pigs

Three different cannulation techniques in pigs were tested with 15 crossbred castrates. Four pigs were fitted with a simple T-cannula, six pigs with a postvalve T-caecum cannula (PVTC cannula) and five pigs with ileocaecal reentrant cannulas. Four diets were tested: a conventional diet, a pectin-rich diet, a crude fibre-rich diet and a semisynthetic diet. For quantitative collection of ileal digesta the PVTC cannulation technique was tested for homogeneity of sampling. Cr₂O₃ and TiO₂ were used as solid phase markers and Co-EDTA as a liquid phase marker. The digestibilities of dry matter, nitrogen, crude fibre, ADF and NDF were determined. Digestibilities measured with re-entrant cannula as a quantitative collection method were sometimes significantly higher (P < 0.05) than with the other cannulas. After correction to 100 % Cr recovery the differences were reduced to less than 5%. Nitrogen digestibility measured with the re-entrant cannula was lower than with the PVTC cannula in the fibre-rich and semisynthetic diets. The Crrecovery was mostly lower than 100%, except with PVTC cannulas and the semisynthetic diet. The recovery rates of Co were higher than those of Cr. In the semisynthetic diet, recoveries of Co and Cr were similar. The recovery rate of TiO₂ with the semisynthetic diet was lower than that of the other two markers. The recovery rates of the markers depended on fibre contents of diets. With the pectin-rich and fibre-rich diets the Cr and Co recoveries were lower than with the control diet. In general, digestibility coefficients measured with the three different cannulation techniques were different. However, when corrections were made for marker recoveries there were only small differences.     

大豆蛋白水解物中肽分子分布的研究

研究采用超滤法与凝胶过滤色谱（GFC）相结合实验方法就大豆蛋白酶解产物寡肽混合物的分子量的分布状况进行了测定,研究结果表明,木瓜蛋白酶与Asl.398蛋白酶的酶解物中以分子量在1000D以下的小肽为主：木瓜蛋白酶解产物中分子量1000D以下的占63.9%,1000-2000D之间的4.64%,2000-4000D之间的占8.21%,4000-10000D之间的占8.20%,分子量10000D以上的占15%;Asl.398蛋白酶酶解物中分子量1000D以下的占72.1%,1000D-2000D的占6.42%,2000D-4000D之间的占2.5%,4000-10000D之间的占3.92%,10000D以上的占15%。     

Bovine claw and limb disorders related to reproductive performance and production diseases

As part of a cross-sectional study of Norwegian Red Cattle, associations of lameness, lesions at the tarsus, claw shapes, and claw lesions with reproductive performance and production diseases were examined. Fifty-five tiestall herds and 57 freestall herds were sampled by computerized systematic selection and 2,665 cows were trimmed and limb and claw disorders recorded by 13 specifically trained claw trimmers during the late winter and spring of 2002. After exclusions, 2,583 cows were included in this study. Most claw lesions were mild (score 1). Prevalence of moderate and severe lesions (score 2 + 3) did not exceed 5% for any of the lesions. Hazard ratios for independent variables were identified using Cox regression analyses incorporating herd as a random effect in a positive stable frailty model. Wounds and swellings at the tarsus were associated with more clinical mastitis [hazard ratio (HR) = 4.0] and teat injuries (HR = 2.5). Moderate and severe heel-horn erosions in first-lactation cows were associated with increased calving interval (HR = 0.60). Moderate and severe hemorrhages of the sole in first-lactation cows were associated with decreased interval from calving to first service (HR = 1.6) and moderate and severe hemorrhages of the sole were associated with more milk fever (HR = 8.6). All hemorrhages of the sole (scores = 1, 2, and 3) were associated with more reproductive hormonal treatments (HR = 2.3). All sole ulcers in first-lactation cows were associated with longer interval from calving to last service (HR = 0.59) and longer calving interval (HR = 0.61), whereas sole ulcers in older cows were associated with longer calving interval (HR = 0.62). All sole ulcers also were associated with more milk fever (HR = 4.8) in all cows. Moderate and severe sole ulcers in older cows were associated with increased interval from calving to first (HR = 0.35) and last (HR = 0.37) service. Moderate and severe white-line fissures in older cows were associated with increased return rate from previous insemination (HR = 2.4). Our study shows that claw disorders are associated with poorer reproductive performance and some production diseases.     

Indirect prediction of herd life in Guernsey dairy cattle

Production and type data were used to investigate the relationships of these traits with herd life data in US Guernsey cows that calved from 1985 through 1990. Two definitions of herd life were used: actual days from birth to disposal (true herd life) and herd life adjusted for milk production (functional herd life). Genetic parameters were calculated with data from cows that had an opportunity to reach 84 mo of age (n = 18,725). Linear type traits were preadjusted for stage of lactation and age at classification. True herd life was preadjusted for age at first calving and for functional herd life, within herd-year quartile ranking for milk yield. The (co)variance components for true and functional herd life, milk, fat, protein, and 15 linear type traits were estimated with multiple-trait REML in an animal model. Heritability estimates for true and functional herd life were 0.12 for both traits. Estimated genetic correlations of herd life with body size traits were from -0.14 to -0.29, with feet and leg traits were from -0.10 to 0.06, and with udder traits were from -0.09 to 0.24. These correlation parameters were used for indirect prediction of herd life from available production and type information in Guernseys.     

包装方式对番木瓜汁品质的影响

以番木瓜破碎打浆制成的番木瓜汁(未灭菌)为研究对象,以总糖、总酸、Vc、顶空CO2和O2含量等为品质判定指标,研究普通、真空、充O2、充CO2包装4种包装方式对番木瓜汁贮藏过程中品质的影响。结果表明,随着贮藏时间的延长,包装番木瓜汁总糖含量不断减小,总酸含量不断上升。其中,普通包装番木瓜汁各指标变化速度最快;真空包装番木瓜汁总糖和总酸含量变化速度较快,但CO2上升速度和Vc损失较小;充O2包装番木瓜汁总糖和总酸含量变化较慢,但CO2上升速度和Vc损失较大;充CO2包装番木瓜汁总糖、总酸、Vc、CO2含量变化均较慢,保质效果相对较好。     

Visual attractiveness depends on colorfulness and color contrasts in mixed salads

The aim of the study was to investigate the impact of color and color combinations on visual attractiveness in food. Ten salad mixes were composed to represent pale-colored salads with no color contrasts and colorful salads with high color contrasts. A consumer study was conducted to discover the kind of color combinations that are seen as visually attractive in salad mixes. The salad portions were photographed and the photographs were introduced in the consumer study (n = 93). In addition, the color values (L*, a*, b*) of the salad compounds were measured using digital image analysis. The color dimensions chroma, saturation, vividness, depth and hue angle were calculated. The total color differences and the maximum differences between the salad components’ color values and color dimensions were calculated to describe the color contrasts in the salad portions. The results of the study indicated that colors and color combinations impacted visual attractiveness and that colorful salad portions with high color contrasts between salad components were more attractive than pale-colored salads with no color contrasts. Saturation and depth of color were the color dimensions associated with attractiveness. Color contrasts with the complementary colors red and green and with light and dark colors were preferred, along with high total color differences. The colorfulness and the color contrasts were associated with freshness, variability and complexity, and consequently with attractiveness. The improvement of visual attractiveness in food using intensive colors and stimulating color combinations is one potential way to tempt consumers to choose and consume more vegetables.     

改性棉活性染料的染色性能分析

采用阳离子改性剂对棉纤维进行阳离子化改性,通过单因素试验分析得到优化的染色工艺,并比较了采用优化染色工艺、同一颜色不同型号的14种活性染料上染改性棉纤维的染色性能,挑选出最适合此工艺、此改性剂的四种活性染料。并再次用这四种染料对原棉和改性棉进行了染色,并比较其上染率和固色率。     

芝麻油掺棕榈油鉴别方法的研究

以4种不同熔点棕榈油与4种芝麻油所配制的128个掺伪芝麻油样品为原料,分别采用全样脂肪酸组成分析法、Sn-2位脂肪酸组成分析法和甘三酯结构分析法对芝麻油中掺棕榈油的鉴别方法进行了研究。结果表明:在全样脂肪酸组成分析法中,当以棕榈酸为标准与芝麻油纯样和国标数据比较时,检出限分别为5%和15%。在Sn-2位脂肪酸组成分析法和甘三酯结构分析法中,当与芝麻油纯样数据比较,分别以亚油酸与棕榈酸含量比值(18:2/16:0)和β-POO(Sn-1-棕榈酸-2,3-二油酸甘油酯)含量为判断标准时,检出限分别为20%和12%。综合这3种方法的检出限高低及分析操作难易程度,初步得出结论:在芝麻油掺棕榈油的鉴别方法中,全样脂肪酸组成分析法是最好的鉴别方法,其余2种方法一般不优先采用,但可作为对上述方法的验证与补充。     

Solid Phase Microextraction for Cheese Volatile Compound Analysis

Cheese headspace volatile compounds were extracted with solid-phase microextraction (SPME) fibers, coated with either polydimethylsiloxane or polyacrylate, and thermally desorbed in the injector port for gas chromatographic (GC) analysis. Results with polyacrylate-coated fibers were better than those with a polydimethylsiloxane fiber. Major cheese volatile components such as volatile fatty acids and 5-lactones were readily extracted by both SPME fibers, but minor components such as volatile sulfur compounds were not observed. SPME-GC patterns were distinctly different among cheese varieties, and characteristic volatile compounds could be identified using multivariate techniques.