基于矿物元素指纹图谱的黑龙江黄豆产地溯源

该研究探讨了矿物元素指纹分析技术对黑龙江黄豆产地溯源的可行性,筛选出判别黑龙江黄豆产地溯源的有效指标。利用电感耦合等离子体质谱仪(inductively coupled plasma mass spectrometry,ICP-MS)测定来自齐齐哈尔和北安2个地域50份黄豆样品中52种矿物元素的含量,并对数据进行了方差分析、主成分分析和判别分析。研究表明,46种矿物元素含量在地域间存在显著差异,通过逐步判别分析筛选出8项元素指标建立黄豆产地判别模型,所建立的模型对黄豆产地整体交叉检验判别率为95.7%。As、Ru、Gd含量在黄豆与土壤间呈显著正相关(P0.05),Tb含量在黄豆与土壤间呈极显著正相关(P0.01),由4种元素建立的判别模型对产地判别准确。因此,上述元素是黄豆矿物元素产地鉴别较可靠的指纹信息指标。     

贵州名优茶与产地土壤矿质元素相关性及其溯源影响的研究

为探究贵州省名优茶产地不同深层土壤对茶叶矿质元素溯源效果的影响,以土壤-茶叶的多矿质元素法结合主成分分析(PCA)、反向传播(BP)神经网络法、逐步线性判别分析(SLDA)对茶叶产地进行溯源。结果显示,不同产地的茶叶和土壤具有独特的矿质元素指纹,茶叶中Fe、Mn、K、Ca、Mg、Cu的含量与土壤中对应元素含量显著相关(P<0.05),以这6种矿质元素含量结合PCA可有效区分茶叶的地理起源;不同深层土壤对茶叶产地的溯源有不同影响,通过SLDA法、BP神经网络法明确了以60~80 cm的土层进行产地溯源的效果最优,产地溯源验证判别率分别为98.5%(SLDA法)和100%(BP神经网络法),并基于SLDA法确定了Zn、Cu、P、Mn、Fe、Mg和K 7种元素构建的贵州名优茶产地溯源模型。此外,研究发现茶叶产地溯源几乎不受茶树品种的影响。本研究结果为贵州省名优茶矿质元素指纹图谱的建设及土壤-茶叶产地溯源的关系研究提供了理论依据。     

基于矿物元素指纹的羊肉产地溯源技术

为探讨矿物元素指纹对羊肉产地溯源的有效性,找寻表征地域特性的元素指标,利用电感耦合等离子体质谱仪分析中国内蒙古自治区阿拉善盟、锡林郭勒盟和呼伦贝尔市3个牧区,及重庆市和山东省菏泽市2个农区脱脂羊肉和土壤样品中4种常量元素(K、Ca、Na、Mg)和13种微量元素(V、Mn、Fe、Cr、Ni、Cu、As、Be、Sb、Zn、Se、Ba、Tl)的含量,对其进行方差分析、相关分析和判别分析。结果表明,羊肉中矿物元素含量组成在地域间有明显差异,农区元素含量普遍高于牧区。脱脂羊肉中Ca、Zn、Be、Ni、Fe、Ba、Sb、Mn和Se9种元素含量的地域差异与土壤相关,它们对农牧区的正确判别率达90%以上,对5个地域的正确判别率在70%～100%之间。利用羊肉中矿物元素指纹分析技术可鉴别和追溯羊肉的产地来源,为羊肉及其他食品的产地溯源研究提供方法参考。     

浦江葡萄同位素与矿物元素特征及地理标志保护模型构建

为探讨稳定同位素与矿物元素在葡萄产地鉴别上的可行性,本研究分别从浦江、浙江其他产地(慈溪、温岭)、上海和安徽4个不同产地采集代表性葡萄样品;通过稳定同位素比率质谱(EA-IRMS)元素分析仪和电感耦合等离子体质谱(ICP-MS)测定其同位素比率与矿物质元素含量,结合化学计量学统计工具对浦江葡萄开展原产地判别研究.结果表...     

不同地域来源牛肉中脂肪酸组成及含量特征分析

建立食品追溯体系是食品安全风险管理的重要措施之一。本研究采用气相色谱仪对来自吉林、宁夏、贵州和河北地区的牛肉脂肪样品进行检测,分析不同地域来源样品中脂肪酸组成及含量差异特征,探讨脂肪酸分析对牛肉产地来源区分的可行性。结果表明,不同地域来源牛肉样品中脂肪酸组成及含量有显著差异,吉林和河北地区牛肉中的SFA(含量均高于62%)显著高于贵州和宁夏地区;宁夏地区牛肉中C16:1和C18:1均显著高于其他地区,含量分别为3.362%和27.041%;贵州与河北地区牛肉中a-C18:3、C20:5和PUFA-n3极显著高于吉林和宁夏地区,吉林地区牛肉中的PUFA-n3含量仅为贵州地区的46%。脂肪酸组成及含量特征分析是鉴别牛肉产地来源一种很有潜力的方法。     

稳定同位素和元素指纹分析在白术产地溯源中的应用

为解决道地药材白术的产地溯源问题,本研究采用稳定同位素比质谱仪(EA-IRMS)和电感耦合等离子质谱仪(ICP-MS)测定了6个产地168种白术中δ¹³C、δ¹⁵N、δ²H、δ¹⁸O和δ³⁴S值及41种矿质元素含量,并结合化学计量学对不同产地白术进行鉴别。结果表明,线性判别分析(LDA)可以区分6个产地的白术。基于不同变量共建立7种不同判别模型,其平均交叉验证率分别为:稳定同位与素(88.17%)、矿质元素(98.67%)、常量矿物元素(41.83%)、 痕量矿质元素(99.33%)、稳定同位素与矿物质元素(100%)、稳定同位素与常量矿质元素(91.83%)以及稳定同位素与痕量矿物质(98.83%)。其中,δ¹⁸O、 δ³⁴S值以及Li、Dy、Sm、Er等稀土元素是影响判别的主要因素,主要由产地地理位置、气候条件和土壤类型决定。综上,基于稳定同位素、矿质元素和化学计量学的方法可对不同产地白术进行产地溯源。     

稻米中同位素与多元素特征及其产地溯源PCA-LDA判别

通过探究谷物中同位素与多元素的地域特色及其产地溯源的可能性,本研究采用稳定同位素质谱和等离子发射光谱质谱法测定稻米中同位素比率和多元素含量,并结合化学计量学中主成分分析(PCA)和线性判别分析(LDA)法建立模型,对不同省份的稻米进行产地溯源判定。结果表明,各地产的稻米中稳定同位素δ15N、δ13C、δD、δ18O数值范围不同,而且Li、Be和Na等其他矿物元素的含量变化较大,Pb、Sr同位素比率也各不相同,具有一定的地域特征。PCA法能够初步辨别各稻米地产,本研究进一步采用PCA-LDA法能够对大区域(黑龙江省、江苏省和辽宁省)的稻米进行产地判别,通过对23个样本进行判别验证,正确率为91%。对于黑龙江省4个地产的稻米样品,由于地理差异性比较小,同时样本数比较少,故只对其中2个产地稻米进行判别。通过同位素比率和多元素的含量的测定再结合化学计量学分析,一定程度上能够区分不同产地的稻米,为稻米产地溯源的可行性提供了方法依据。     

利用稳定同位素进行农产品溯源研究进展

随着消费者对农产品质量与安全要求的提高,农产品溯源保持着良好的发展态势。稳定同位素在农产品研究中应用广泛,主要包括农产品产地溯源、真伪鉴别等。在产地溯源方面,研究较多的是牛肉、羊肉、牛奶、葡萄酒、蜂蜜、水产品、茶叶、谷物等农产品。一直以来,缩小溯源区域范围是产地溯源的难点和重点。稳定同位素技术与矿物元素技术、氨基酸技术、脂肪酸技术相结合是缩小溯源区域范围的最佳方法。在农产品真伪鉴别方面,农产品掺杂掺假形式多样、手段复杂,消费者难以辨别。在农产品加工过程中稳定同位素分馏方面,研究已经展开,且逐步深入。本文综述了2015—2020年稳定同位素在农产品产地溯源、真伪鉴别以及加工过程中的分馏研究进展,阐述了稳定同位素与其他技术结合进行农产品溯源区域范围的研究,并对利用稳定同位素进行农产品溯源研究予以总结和展望。     

不同牧场及饲养方式下阿拉善双峰驼乳脂肪酸特征及产地溯源研究

为研究距离较近的不同牧场及不同饲养方式下双峰驼乳脂肪酸特征,并建立产地溯源模型,本试验从内蒙古自治区阿拉善左旗采集5个牧场共139份双峰驼乳样品,用气相色谱法测定驼乳中脂肪酸含量,并利用脂肪酸指纹特征建立不同牧场及不同饲养方式下驼乳的溯源模型。结果表明,不同牧场及不同饲养方式下的驼乳中含量较高的脂肪酸为棕榈酸、油酸、硬脂酸及肉豆蔻酸。相比谷饲,草饲方式下驼乳的饱和脂肪酸(SFA):单不饱和脂肪酸(MUFA):多不饱和脂肪酸(PUFA)比例(S:M:P为12:6:1)更接近联合国粮农组织(FAO)和世界卫生组织(WHO)建议的居民膳食S:M:P比例(1:1:1),更符合居民营养需求。建立的不同牧场及饲养方式下驼乳的溯源模型交叉验证准确率分别为82.7%及95.0%。此外,硬脂酸、棕榈油酸、木焦油酸、豆蔻油酸、二十碳五烯酸、二十二碳二烯酸、十七烷酸、亚油酸、花生酸、γ-亚麻酸、花生二烯酸、十五烷酸、反亚油酸、二十碳烯酸及二十一烷酸是鉴别牧场来源的关键重要性因子,二十碳五烯酸、二十碳烯酸、十五烷酸、木焦油酸、硬脂酸、棕榈油酸、十三烷酸、十五碳烯酸、十七碳烯酸、花生酸、二十一烷酸、豆蔻油酸及肉豆蔻酸是鉴别不同饲养方式的关键重要性因子。综上,脂肪酸指纹分析法可有效鉴别短距离的双峰驼乳来源,为双峰驼乳近距离的产地溯源及真实性鉴别提供了技术支持。     

茶叶产地溯源与鉴别检测技术研究进展

茶叶是我国重要的特色农产品,地域特色和品质特征明显,溯源与鉴别检测技术对保证其产地和品质真实性具有重要意义.本文系统介绍了国内外茶叶产地溯源和种类鉴别中稳定同位素、多矿物元素、近红外光谱和化学指纹图谱等检测技术的研究进展,分析茶叶产地溯源与鉴别检测技术面临的关键问题,提出茶叶产地溯源和鉴别的研究重点,对我国茶叶原产地保护具有积极的借鉴作用.     

基于矿质元素指纹的粉葛产地溯源研究

为明确矿质元素指纹对粉葛产地鉴别的可行性,筛选出鉴别粉葛产地的有效指标,本研究采用电感耦合等离子体质谱仪(ICP-MS)测定陕西、湖北、广西3个地域粉葛和土壤样品中B、Na、Mg、P、K、Ca、Mrn、Co、Cu、Zn、Rb、Sr、Mo、Cd、Cs、Ba、La、Ce、Pr、Nd、Sm和Ti 22种矿质元素含量,并结合主...     

糯米糍荔枝叶片矿质养分含量充足范围的确定

对深圳市4个典型丰产园糯米糍荔枝叶片7种矿质养分(氮、磷、钾、钙、镁、锌和硼)含量的统计分析表明:采样地点和生育时期均对叶片营养元素含量有显著的影响。四个关键生育时期(末次秋梢老熟期、花芽形态分化期、谢花期和果实成熟期)的单株样与混合(多株)样的供试矿质养分含量之间大部分没有显著差异。本研究根据丰产园糯米糍荔枝叶片混合样的分析结果提出了7种矿质养分的充足含量范围。     

CO2浓度升高与施氮对薏苡苗期营养元素吸收运输的影响

为明确大气CO₂浓度升高及氮肥施用对薏苡(Coix lacryma-jobi L.)苗期营养元素吸收运输的影响,本研究以兴仁白壳薏苡为试验材料,采用盆栽控制试验,通过人工气候箱模拟CO₂浓度升高,探究薏苡各器官中营养元素对CO₂浓度升高和施用氮肥的响应。结果表明,CO₂浓度升高使薏苡根中TOC含量显著增加15.82%;叶、茎中TP含量显著增加18.98%、29.41%(P<0.05);叶、根中N含量显著减少8.15%、8.31%(P<0.05);叶、茎、根中K含量无显著差异。施氮使薏苡叶、茎、根中N含量显著增加19.52%、28.42%、23.29%;叶、茎中TP含量显著增加14.60%、51.96%(P<0.05);根中K含量显著减少22.57%(P<0.05);叶、茎、根中TOC含量无显著差异。两者交互作用下,薏苡茎、根中N含量显著增加6.49%、8.99%;叶中TP含量显著增加15.33%(P<0.05);叶中N含量显著减少4.22%;叶、茎中K含量显著减少18.47%、33.25%(P<0.05);叶、茎、根中TOC含量无显著差异。在CO₂浓度升高条件下,薏苡叶片中中量元素S和微量元素Cu、Zn、Ni含量,分别显著减少18.06%、54.01%、37.96%、50.99(P<0.05);而茎中Mn、Cu、Zn、Ni含量,分别显著增加90.20%、70.55%、46.80%、149.50%(P<0.05)。CO₂浓度升高能促进Mg、S根向茎的运输以及Zn、Mn茎向叶的运输,施用氮肥能促进Fe茎向叶的运输。综上所述,CO₂浓度升高和氮肥施用会影响薏苡不同器官矿质离子的吸收及选择性运输能力,从而维持植物体内营养元素平衡。本研究结果可为深入认识未来大气环境变化下,薏苡对营养元素的需求变化特征,以及薏苡栽培中施肥策略的选择提供科学依据。     

Human milk fat globules from different stages of lactation: a lipid composition analysis and microstructure characterization

The physicochemical properties of human milk fat globules (MFG) at different lactation stages from Danish mothers and the microstructure changes of MFG membrane (MFGM) at varied temperatures were investigated, and the relationship between chemical composition and the microstructure of MFGM was elucidated. The fat content in MFG was found to be significantly increased as lactation progressed, and colostrum MFG had the largest mean diameter of 5.75 ± 0.81 μm and the lowest ζ potential of -5.60 ± 0.12 mV. Chemical composition analyses of MFG revealed the following: (i) Colostrum milk fat constituted higher content in PUFAs (ω-6, and long-chain ω-6 and ω-3) than transitional and mature milk fats, with the corresponding lower content of SFA in its sn-2 position. (ii) The content of polar lipids among total lipids varied during lactation course (maximized at transitional stage); however, in terms of subclasses of polar lipids, no significant change of the relative content of sphingomyelin was observed, while the content of phosphatidycholine in mature milk was higher than that in colostrum and transitional milk. (iii) Inspection of fatty acid composition in phospholipids from different lactation milk revealed no remarkable and regular changes could be generalized; and no obvious difference of the morphologies of MFGM at different lactation stages can be visualized. An investigation of the microstructure change of MFGM vs temperature demonstrated that the segregated domains became larger as temperature decreased to 4 °C, while it became smaller when increased to 37 °C. This phenomenon indicated that, in addition to sphingimyelin and cholesterol, phospholipids might also contribute to increasing the segregated domains at lower temperature, while, at elevated temperature, these domains could be diminished, most likely due to a restructuring or distributing of sphingimyelin and cholesterol.     

苹果酸对泌乳早期奶牛泌乳性能和代谢产物的影响

选用28头经产奶牛,根据泌乳期、上一泌乳期305d的产奶量和预产期,采用随机区组设计分为4组,研究苹果酸(07、0、140和210g/d)对泌乳早期奶牛采食量、泌乳性能、血液代谢产物和尿酮浓度的影响。结果表明:日粮添加苹果酸对奶牛的采食量、乳脂率、乳蛋白率、乳糖率和乳干物质率无显著影响,140g/d组和210g/d组产奶量和饲料转化效率显著高于对照组(P<0.05)。添加苹果酸后,140g/d组和210g/d组血浆葡萄糖浓度显著高于对照组(P<0.05),而血浆游离脂肪酸和β-羟丁酸浓度显著低于对照组(P<0.05);140g/d组和210g/d组尿酮浓度显著低于对照组和70g/d组(P<0.05)。根据试验结果,苹果酸适宜添加量为140g/d。     

Adequacy of vitamin A and fat in the breast milk of lactating women in south Sri Lanka

OBJECTIVE: To determine vitamin A (retinol) and fat concentrations in breast milk during early lactation. METHODS: Healthy lactating women (n 88) aged between 18 and 35 years were randomly selected for the study from urban, semi-urban, rural and estate (plantation) sectors of Galle District. Their anthropometry was recorded; breast milk samples were collected from the right breast one hour after the last feed. Breast milk retinol was determined by HPLC and fat content by the crematocrit method. RESULTS: Subjects were in the 2nd to 9th month of lactation. Retinol concentrations of the breast milk samples ranged from 0.10 to 2.46 micromol/l, with a mean of 0.50 micromol/l, and correlated positively with parity (Pearson correlation coefficient, r = 0.307; P = 0.01) and negatively with period of lactation (r = -0.209; P = 0.05). The fat content of breast milk ranged between 5.09 and 56.46 g/l with a mean of 26.95 g/l. A significant difference in either breast milk fat or retinol content and mean birth weight of the babies was not seen between the groups. The ratio of retinol to fat in breast milk was positively correlated with weight (r = 0.274; P = 0.01) and height (r = 0.328; P < 0.001) of the mothers. CONCLUSIONS: In this primary investigation on breast milk quality the fat content was found to be marginal; the majority of lactating mothers (92.0%) were not providing the minimum daily requirement (1.05 micromol/l) of retinol to their babies.     

Analysis of the peptide profile of milk and its changes during thermal treatment and storage

In this study a new method was developed for analysis of the low molecular weight protein fraction of milk, allowing a simple and fast overview of the peptide profile of various milk samples. For this purpose, immobilized metal affinity chromatography (IMAC) was coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). By this technique, two major peptides in milk could be identified as fragments of alpha-s1-casein. During heat treatment of raw milk, five new peptides were generated, the origin of which could be assigned to the casein fraction. Storage experiments with extended shelf life milk at 4 degrees C did not show any changes in the peptide profile, whereas in ultra high temperature milk stored at room temperature, one peptide increased significantly, which was identified as the N-terminus of alpha-s1-casein. The peptide was assumed to be formed in an enzymatic reaction, which was confirmed in a storage experiment with sterilized milk. Analyses of different commercially available milk samples confirmed the results obtained with the heated and stored milk. Furthermore, differences in the peptide profiles of the samples, probably due to different cow breeds or lactation stages, were observed. These results establish IMAC prior to MALDI-TOF-MS as a valid tool for the rapid analysis of the peptide profile of milk.