基于稳定同位素比率和矿质元素含量分析的进口大豆产地溯源

目的探索稳定同位素比率和矿质元素含量分析用于进口大豆溯源的可行性。方法采用稳定同位素质谱测定阿根廷和巴西大豆中的4种轻元素碳、氮、氢、氧的稳定同位素比率,采用电感耦合等离子体质谱测定大豆中的38种矿质元素含量,对结果进行方差分析,并运用正交偏最小二乘法判别分析构建大豆产地判别模型。结果大豆的碳、氮、氢、氧稳定同位素比率(δ~(13)C、δ~(15)N、δ~2H、δ~(18)O)和镁、铝、钪等26种矿质元素含量具有明显的地域差异,结合多元统计学方法,可以有效地区分阿根廷和巴西所产的大豆,交叉验证的判别准确率均达到了100%。结论稳定同位素比率和矿质元素含量分析结合多元统计学方法可对阿根廷和巴西大豆进行有效的产地溯源,具有较大的应用前景,有望为进口大豆产地溯源技术的研究提供新的方法。     

稳定性C、H、O、N、S同位素在绿茶产区溯源的应用

为确定稳定同位素对绿茶溯源的可行性。利用同位素质谱仪测定来自安徽、福建、贵州、山东、四川、浙江、西藏7地区的绿茶样品的碳、氢、氧、氮、硫同位素。通过比较分析不同地域来源的绿茶中稳定性碳、氢、氧、氮、硫同位素组成特征。结果表明,各地区绿茶中稳定性碳、氢、氧、氮、硫同位素存在一定差异。多同位素指标组合判别效果好于单一同位素指标的判别效果,稳定性碳、氢、氧、氮、硫同位素指标组合分析是绿茶产地溯源的有效指标,准确率可达84.8%。利用稳定性碳、氢、氧、氮、硫同位素指标与多元统计分析方法相结合可以对不同地域来源的绿茶进行有效区分。     

基于稳定同位素与稀土元素指纹特征的大桃产地判别分析

研究建立大桃产地判别技术,为保护地理标志产品、追溯原产地来源提供理论依据。本研究采集河北省顺平县、乐亭县、永清县和北京市平谷区共4个产地的92份普通大桃样品,利用元素分析-稳定同位素质谱仪测定大桃中稳定性碳、氮、氢、氧同位素比值,利用电感耦合等离子体质谱仪测定16种稀土元素含量,结合多重比较分析和一般判别分析建立大桃的产地判别模型。多重比较分析结果表明,平谷大桃的氮同位素与其他产地差异显著(P0.05),平谷、顺平丘陵山区与乐亭县大桃的碳同位素比值差异显著(P0.05),稀土元素铈、铕、钆和铒含量的地域分布差异最为明显;根据多重比较分析结果,将4种稳定同位素(δ~(13)C、δ~(15)N、δ~2H和δ~(18)O)结合8种稀土元素作为变量(钇、铈、铕、钐、镨、钕、钆和铒)进行一般判别分析,确定3个具有显著相关性(P0.05)的判别函数,以此建立的判别模型对不同产地的大桃原始样本回代检验和交叉检验的整体正确判别率分别为97.8%和95.7%。利用稳定同位素和稀土元素指纹特征结合化学计量学方法对小空间尺度下的大桃产地判别具有可行性。     

河北太行山中麓大枣产地溯源初探

目的探索稳定同位素碳氮对大枣产地溯源的可行性。方法用同位素比质谱仪(isotopic ratio mass spectrometry,IMRS)测定河北省赞皇、行唐、阜平3县10个枣园的大枣果肉中的δ~13C和δ~15N值,通过聚类分析,研究太行山中麓大枣枣肉中同位素组成的区域分布。结果阜平县不施肥组c3自成一类,赞皇县50%样品聚为第二类,行唐100%样品聚为第三类,赞皇和阜平剩余样品与行唐样品存在交叉。结论赞皇、行唐、阜平三地大枣枣肉中C、N同位素组成存在差异,用同位素技术对大枣进行产地溯源是可行的。     

青梅酒中乙醇稳定碳同位素的测定

建立了气相色谱-稳定同位素比值质谱法测定青梅酒中乙醇的稳定碳同位素比值(δ~(13)C)。青梅酒与丙酮混合后,用GC-IRMS法测定乙醇的δ~(13)C值。结果表明,该方法能快速准确的测定青梅酒中乙醇的碳稳定同位素比值,准确率和精确度均满足测定需求。通过测定4个品牌青梅酒中乙醇的δ~(13)C值,品牌A、B、C和D青梅酒中乙醇δ~(13)C值分别为-13.87‰~-13.56‰、-14.30‰~-13.60‰、-14.29‰~-13.86‰和-14.09‰~-13.52‰。表明本方法前处理简单、测定结果准确,可用于青梅酒的产地溯源。     

碳氮稳定同位素鉴别有机奶粉

本文以有机奶粉和非有机奶粉为研究对象,以有机奶粉和非有机奶粉的碳稳定同位素比值和氮稳定同位素比值为研究目标,探索有机奶粉和非有机奶粉的碳、氮稳定同位素组成的差异性。研究结果显示,有机奶粉的碳稳定同位素比值(δ~(13)C)整体趋势更负于非有机奶粉的δ~(13)C值,有机奶粉的氮稳定同位素比值(δ~(15)N)稍低于非有机奶粉的δ~(15)N值。尽管两种样品的δ~(13)C值和δ~(15)N值的数据范围有交叉,但是根据统计分析,有机奶粉的δ~(13)C值和δ~(15)N值与非有机奶粉的δ~(13)C值和δ~(15)N值具有差异性(p0.05)。有机奶粉与非有机奶粉δ~(13)C值和δ~(15)N值的差异性主要受牛奶来源的影响,主要与动物的饲料、牧场土壤及肥料等有关。研究结果虽然经有限的样本获得,但是该方法对监管有机食品的真实性具有一定的参考价值。     

基于碳、氮稳定同位素技术的羊肉产地溯源可行性研究

选择内蒙古12个旗县,共计141只羊的背最长肌、股二头肌、臂三头肌、和腹下肌四个部位肌肉,共564份样品,运用元素分析仪-同位素比质谱仪联用(EA-IRMS)法测定样品δ13C和δ15N值,确定不同部位、不同产地羊肉的同位素组成,以及用其组成特征进行羊肉产地溯源的可行性分析。结果显示,四个部位的δ13C、δ15N值差异性不显著(p>0.05);用δ13C和δ15N值进行二维投射和层聚类分析,可以完全的将呼伦贝尔和锡林郭勒放牧羊肉与西部区四子王旗、和林县和达拉特旗舍饲羊肉区分。结果表明,通过稳定同位素δ13C和δ15N值可以区分部分旗县羊肉样品,为通过该方法实现肉制品的产地溯源提供了技术支撑和理论依据。     

不同产地三文鱼的稳定同位素指纹特征及原产地溯源

本研究从深圳口岸获取我国三文鱼主要进口国（法罗群岛、挪威、智利、加拿大以及澳大利亚）的三文鱼样品共16?份,并采集中国产三文鱼（虹鳟）样品2?份,分析三文鱼肌肉、表皮、鳞片以及骨骼中的碳、氮、氢、氧、硫稳定同位素比值,比较不同产地以及不同部位同位素分布差异,采用判别分析对不同产地进行判别。三文鱼的碳、硫以及氢、氧稳定同位素具有显著的产地差异。不同组织之间同位素呈现明显的同位素分馏效应。鳞片以及表皮同位素比值对产地的指示效果优于肌肉和骨骼,结果表明采用稳定同位素能完全将以上产地的样品区分开,且还能将中国的虹鳟与进口的三文鱼进行区分。对市场随机购买的6?份三文鱼样品的产地鉴别结果表明,稳定同位素技术能有效鉴别市场中三文鱼的产地造假行为,可用于对市场上三文鱼的产地追溯,以期为我国食品安全提供技术保障。     

稳定同位素-有机成分结合判别猕猴桃的产地来源

目的:分析猕猴桃的稳定同位素、有机成分组成特征与含量随地域变化的规律,各指标组合对样品产地的鉴别效果,为猕猴桃产地溯源指标体系的建立和产地鉴别提供依据。方法:利用稳定同位素比率质谱仪检测来自陕西省周至县和眉县、四川省沐川县、湖南省永顺县90个猕猴桃样品的稳定碳、氮、氢同位素比率,用理化分析方法测定VC、VE、总糖含量,探讨各指标随地域变化的规律;利用判别分析,研究稳定同位素与有机成分结合对猕猴桃产地的判别效果。结果:不同产地猕猴桃的δ15N值、δ2H值、VC、VE及总糖含量具有显著性差异,δ13C值无显著差异(P0.05)。猕猴桃中δ13C值具有随海拔高度和年均温度的升高而增大的趋势,δ15N值受土壤类型和施肥的影响较大,δ2H值具有随海拔升高而降低的趋势。利用C、N、H同位素指标对不同省份、亚地区猕猴桃产地的总体正确判别率分别为57.8%和66.6%,结合VC、VE和总糖指标总体正确判别率分别提高到88.9%和96.7%。结论 :N、H同位素对猕猴桃产地的判别能力优于C同位素,VC、VE及总糖可辅助区分地理环境相似地区的样品。稳定性同位素与有机成分结合可明显提高猕猴桃产地的判别效果。     

基于果核壳的元素和稳定同位素比值测定及车厘子产地分析

该研究应用电感耦合等离子体质谱仪（ICP-MS）,元素分析-稳定同位素比质谱仪（EA-IRMS）对车厘子果核壳中37种元素含量和氢、氧、碳、氮稳定同位素比值进行测定,并应用于车厘子产地分析中。车厘子去果肉和果仁后,将果核壳烘干并研磨成粉末,微波消解后通过ICP-MS对元素含量进行测定,果核壳粉末通过元素分析-稳定同位素比质谱仪对氢、氧、碳、氮稳定同位素比值（δ2H、δ18O、δ13C和δ15N）进行测定。应用上述方法对澳大利亚、美国、新西兰、智利和中国的车厘子样品进行元素含量和稳定同位素比值的测定,并对检测结果进行方差分析、主成分分析、聚类分析和判别分析,对车厘子产地的归属进行研究。研究结果表明基于车厘子果核壳的元素含量和稳定同位素比值综合分析,可以对车厘子产地进行区分,其中Mn、Co、Rb、Sr、Ba和δ2H组合指标整体交叉检验判别准确率92.1%。     

Isolation,Composition, Structure,Properties, Modifications,and Uses of Yam Starch

Starch is the major carbohydrate in yam tubers and can amount up to 80% of the dry matter. The starch quality determines the quality of food and industrial products made from yam tubers. This review summarizes the present knowledge of the isolation, composition, structure, property, modifications, and uses of starches from diverse yam species. Compared with other tuber and root starches, there is a lack of systematic information on the yam starches. This hinders the further development of yams as sustainable crops as well as the value‐added processing of the starches. Therefore, suggestions on how to better understand and utilize these starches are provided.     

Survey of trace elements (Al,As, Cd,Cr, Co,Hg, Mn,Ni, Pb,Se, and Si) in retail samples of flavoured and bottled waters

Concentrations of eleven trace elements (Al, As, Cd, Cr, Co, Hg, Mn, Ni, Pb, Se, and Si) were measured in 39 (natural and flavoured) water samples. Determinations were performed using graphite furnace electrothermetry for almost all elements (Al, As, Cd, Cr, Co, Mn, Ni, Pb, and Si). For Se determination hydride generation was used, and cold vapour generation for Hg. These techniques were coupled to atomic absorption spectrophotometry. The trace element content of still or sparkling natural waters changed from brand to brand. Significant differences between natural still and natural sparkling waters (p < 0.001) were only apparent for Mn. The Mann–Whitney U-test was used to search for significant differences between flavoured and natural waters. The concentration of each element was compared with the presence of flavours, preservatives, acidifying agents, fruit juice and/or sweeteners, according to the labelled composition. It was shown that flavoured waters generally increase the trace element content. The addition of preservatives and acidifying regulators had a significant influence on Mn, Co, As and Si contents (p < 0.05). Fruit juice can also be correlated to the increase of Co and As. Sweeteners did not provide any significant difference in Mn, Co, Se and Si content.     

Mineral contents of some southern Italian wines. II. Determination of Li, Na, Mg, K, Ca, Co, As, Rb, Sr, Ag, Sb, Ba

Following our study of the mineral contents of some Southern Italian wines, this work reports on the detection of 12 elemental components. The elements were determined using ICP-AES, flame atomic emission or absorption spectroscopy. The values determined for Li, Na, Mg, K, Ca, Rb, Sr and Ba were within the usual ranges for wines (average values for these elements were: 0.010, 26.2; 94.4; 888; 94.0; 3.30, 0.82 and 0.11 mg/l respectively). All the wines contained low levels of As, the concentrations of which were always under 0.20 mg/l, the maximum level permitted by E.E.C. standards. The measuring of Co, Ag, and Sb led us to ascertain, in all the wines, concentrations lower than 0.01 mg/l for Co and Ag and below the instrumental detection level for Sb (0.06 mg/l). In a previous study wines from D.O.C. areas of Southern Italy were analysed by the technique of inductively coupled plasma atomic emission spectroscopy (ICP-AES), for 14 minerals. This paper deals with further investigation of the mineral composition of the same wines for different metal constituents, analysed by ICP-AES, flame atomic emission, or atomic-absorption spectroscopy (two techniques). The first technique was applied to the detection of Co, As, Sr, Ag, Sb, and Ba. The alkaline metals Li, Na, K, and Rb were determined by flame atomic emission, a technique which possesses better detection limits for these elements. For Mg and Ca the atomic absorption methods were applied.     

卷烟中锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量分析

采用微波消解-电感耦合等离子体质谱法测定了41个牌号烤烟型卷烟和雪茄烟样品烟丝中的锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量,并按照类型和价位对卷烟中这10种有害元素含量进行了统计分析。结果发现:①卷烟中锂和铜的含量较高,铊的含量很低,铬、镍、镉、铅、砷、硒和钼7种元素的平均含量为0.55～4.42μg/g;②雪茄烟中铬、镍、砷、钼、镉、铊和铅的含量一般高于烤烟型卷烟,而硒元素的含量则相反,但差别较小;烤烟型卷烟中锂和铜的含量与雪茄烟没有显著差异;③高档卷烟中的锂、镍、镉、铊和铬含量较低,而砷、铅的含量较高;不同价位卷烟的铜、硒和钼含量差异不显著。     

Varied Composition of Tocochromanols in Different Types of Bran: Rye,Wheat, Oat,Spelt, Buckwheat,Corn, and Rice

The profiles of tocopherol (T) and tocotrienol (T3) homologues in 37 samples of seven different types of bran (rye, wheat, oat, spelt, buckwheat, rice, and corn), available on the Polish market, were studied. Tocochromanols were identified and quantified by reverse phase-high-performance liquid chromatograph/fluorescence detector and reverse phase-ultra performance liquid chromatography-electrospray ionization/mass spectrometry. Only rice bran contained all eight tocochromanol types. Corn bran lacked β-T3; rye, wheat, oat, and spelt bran lacked γ-T3 and δ-T3; and buckwheat bran lacked β-T3, γ-T3, and δ-T3. In buckwheat and corn bran tocopherols predominated (98 and 78%, respectively); whereas rye, wheat, oat, spelt, and rice bran were rich in tocotrienols (78, 76, 66, 87, and 66%, respectively). The average total tocochromanol contents in the oat, corn, spelt, buckwheat, wheat, rye, and rice bran were 5.5, 16.2, 15.8, 14.7, 12.8, 10.7, and 9.1 mg/100 g of dry weight, respectively. Tocochromanol concentrations in samples of the same type bran from different sources varied considerably. Better labeling of bran products to reflect this variation would assist with control of vitamin E daily dietary requirements.     

Optimization of extraction conditions of total phenolics, antioxidant activities, and anthocyanin of oregano, thyme, terebinth, and pomegranate

The purpose of this study was to evaluate the total phenolic extracts and antioxidant activity and anthocyanins of varieties of the investigated plants. These plants include oregano, thyme, terebinth, and pomegranate. The optimum extraction conditions including temperature and solvent of the extraction process itself were investigated. Total phenolic and anthocyanin extracts were examined according to Folin-Ciocalteu assay and Rabino and Mancinelli method, respectively. The effect of different extracting solvents and temperatures on extracts of phenolic compounds and anthocyanins were studied. Plant samples were evaluated for their antioxidant chemical activity by 2, 2-diphenyl-1-picrylhydrazl assay, to determine their potential as a source of natural antioxidant. Results showed that all tested plants exhibited appreciable amounts of phenolic compounds. The methanolic extract (60 °C) of sour pomegranate peel contained the highest phenolic extract (4952.4 mg/100 g of dry weight). Terebinth green seed had the lowest phenolic extract (599.4 mg/100 g of dry weight). Anthocyanins ranged between 3.5 (terebinth red seed) and 0.2 mg/100 g of dry material (thyme). Significant effect of different extracting solvents and temperatures on total phenolics and anthocyanin extracts were found. The methanol and 60 °C of extraction conditions found to be the best for extracting phenolic compounds. The distilled water and 60 °C extraction conditions found to be the best for extracting anthocyanin.     

Analysis of cheese for histamine, tyramine, tryptamine, histidine, tyrosine, and tryptophane

A method is described for determining the content of selected biologically active amines (histamine, tyramine, tryptamine) and amino acids (histidine, tyrosine, tryptophane) in cheeses by high performance liquid chromatography. The amines and amino acids were quantified by employing a counter ion-containing mobile phase and by comparing peak areas of high performance liquid chromatography charts for sample cheeses versus standard cheeses containing known amounts of added amines based on dual injections of samples and standards. Recovery of amines and amino acids varied from 87.5 to 111%. Histamine, which has been associated with food poisoning in concentrations of 185 mg/100 g in Swiss cheese and 180 to 500 mg/100 g in fish, was found in concentrations above 500 mg/100 g in Swiss cheese. The high performance liquid chromatography analytical method should be useful for screening to detect cheese samples containing toxic amounts of histamine and for research studies designed to determine the cause and effect relationships for histamine production in cheese.     

Physicochemical,morphological, thermal,pasting, and textural properties of starch acetates

Acetylated starches are a commercially important group of modified starch known for their reduced retrogradation tendency, high clarity, low viscosity, high swelling power, and lower gelatinization temperature and time. Due to these remarkable properties, acetylation is a commonly used chemical modification for preparing stabilized starches. This review summarizes the methods used for preparation of starch acetates and corresponding effects of acetylation on morphological, thermal, pasting, digestibility, textural, and other functional characteristics of starches isolated from various botanical sources. Starch acetates are also useful as packaging material, as wall material for encapsulating active ingredients, and to improve the storage stability of different products.     

鲁浙粤豫苏冀六省造纸工业近年发展特点之比较

对我国6省造纸工业具有不同地方特色的四种发展模式及前景进行了分析和预测。