Using <Superscript>1</Superscript>H and <Superscript>13</Superscript>C NMR techniques and artificial neural networks to detect the adulteration of olive oil with hazelnut oil

The lack of any official analytical method to detect the adulteration of olive oil with a low percentage of hazelnut oil is explained by the similarities in the chemical compositions of both kinds of oils. To counter this problem, an artificial neural network based on ¹H-NMR and ¹³C-NMR data has been developed to detect olive oil adulteration, and the results from this ANN are presented here. A training set consisting of hazelnut oils, pure olive oils, and olive oils blended with 2–20% hazelnut oils was used to design and train a multilayer perceptron with 100% correct classifications. This mathematical model was also validated using an external validation set of blend samples (3–15%) and genuine samples. The detection limit of the model was around 8%.     

Online determination of <Superscript>2</Superscript>H/<Superscript>1</Superscript>H and <Superscript>13</Superscript>C/<Superscript>12</Superscript>C isotope ratios of cinnamaldehyde from different sources using gas chromatography isotope ratio mass spectrometry

The combination of gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) and gas chromatography-pyrolysis-isotope ratio mass spectrometry (GC-P-IRMS) is applied to the authenticity assessment of cinnamaldehyde from various sources. For that reason, cinnamon oils were self-prepared by steam distillation from three different varieties of cinnamon bark on the market, C. ceylanicum (ceylon), C. cassia (cassia) and C. burmanii (cassia vera). Furthermore, the so-called wood cinnamon was investigated, which is produced from the outer bark of older branches of cinnamon of minor quality. Self-prepared oils were analysed from commercial cinnamon powder. In addition several commercial samples of cinnamon oil and cinnamaldehyde, some of them declared to be natural, were investigated. ²_V-SMOW and ¹³C_V-PDB values of cinnamaldehyde were determined and characteristic authenticity ranges were deduced, allowing the differentiation between synthetic and natural samples. By correlation of both the ²_V-SMOW and ¹³C_V-PDB values, characteristic authenticity ranges were defined for ceylon, cassia and wood cinnamon. The ²_V-SMOW and ¹³C_V-PDB values of cassia vera samples are in the range of cassia. By comparing the ²_V-SMOW values of different self-prepared samples (ground bark, distillate) of cinnamon determined by TC/EA-IRMS with the corresponding GC-IRMS values, online GC-IRMS methods are proved to be essential in the authentication of complex natural products.     

Authenticity control of pistachios based on <Superscript>1</Superscript>H- and <Superscript>13</Superscript>C-NMR spectroscopy and multivariate statistics

¹H- and ¹³C-NMR-spectra of pistachio oil from Iran, USA and Turkey were analysed with multivariate statistics in order to classify pistachios according to their countries of origin. The integrals of the resonances of the NMR-spectra contain information about the fatty acid composition of pistachio oil which is supposed to reflect the climatic conditions at the crop area. Consequently, NMR-spectroscopy was thought to be a suitable method for the distinction of those pistachio oils. Cluster analysis was found to lead to a distinction between pistachio samples from Turkey and other countries. Principle component analysis was used to extract components from the data, which primarily contain the information about unsaturated acyl chains in the oil and allowed to assign the samples very well to their respective countries of provenance. Linear discriminant analysis provides similar results with low error rate estimations. It was demonstrated that those data gained by ¹H- and ¹³C-NMR-spectroscopy from samples with unknown provenance can be classified by principle component analysis as well as by discriminant analysis.     

Wine Analysis and Authenticity Using <Superscript>1</Superscript>H-NMR Metabolomics Data: Application to Chinese Wines

A NMR-based metabolomics method was developed to semiautomatically quantify the main components of wine. The method was applied to discriminate wines from two regions of China, Shanxi and Ningxia, which were produced by 6 wineries and for 6 vintages. Two different cultivars, Cabernet Sauvignon and Beihong, were used for winemaking. The method allowed the quantification of 33 metabolites including sugars, amino acids, organic acids, alcohols, and phenolic compounds. Depending on the compounds, the LOD values were in the range of 0.6 to 116 mg/L. The results showed that NMR-based metabolomics combined with multivariate statistical analysis allowed wine separation as a function of terroir and cultivar. Nevertheless, wine differentiation as a function of wineries and ageing would need to be examined more carefully.     

Chemometrics-Enhanced Micelle-Mediated Extraction Spectrophotometric Method for Simultaneous Determination of Cu<Superscript>2+</Superscript> and Zn<Superscript>2+</Superscript> in Medicinal Plant,Rice and Water Samples Using Continuous Wavelet Transform

A new micelle-mediated extraction method for the pre-concentration of trace amounts of Cu²⁺ and Zn²⁺ as a prior step to their simultaneous spectrophotometric determination has been developed in various samples. The analytes were complexed with new synthesized ligand 4,4′-((4-chlorophenyl)methylene)bis(1,3-diphenyl-1H-pyrazol-5-ol) (CPBMPY) and Triton X-100 was added as a extraction agent. The optimal reaction and extraction conditions were optimized and the analytical characteristics of the method were obtained. The detection limit of the method was 0.90 and 0.30 ng mL^?1 for Cu²⁺ and Zn²⁺, respectively. Continuous wavelet transformation (CWT) of visible spectra as a very simple and accurate method was developed for the simultaneous determination of binary mixtures of Cu²⁺ and Zn²⁺ ions. A zero-crossing technique was applied on the transformed signals and the constructed calibrations were tested by analyzing the composition of the different binary mixtures. The proposed procedure successfully was applied to analysis of water, rice, and medicinal plant and reference material samples. The amounts of metal ions obtained by the proposed methods were in good agreement with those obtained by Graphite furnace atomic absorption spectrometry.     

Antioxidant Capacity of Hydrophilic Food Matrices: Optimization and Validation of ORAC Assay

It is widely accepted that ORAC is a useful method for assessing food extracts that contain various antioxidants. The principal aim of this study was to validate the ORAC assay. We first identified parameters that can interfere with the ORAC assay and we optimized it. Then, experiments were conducted to determine the limits of linearity and response function, to determine the accuracy profiles to circumvent some of the drawbacks of traditional validation procedures. Trueness, selectivity and limits of quantification of the method were also determined. Our objective of ORAC method validation is thus to give guarantees that most of the results generated during use of this method will be close enough to unknown true value of antioxidant capacity of food matrices. The validation results indicate that the described method will give accurate and reliable results for Trolox equivalent values ranging from 50 to 200 μmol/L.     

Elemental Profile and <Superscript>87</Superscript>Sr/<Superscript>86</Superscript>Sr Isotope Ratio as Fingerprints for Geographical Traceability of Wines: an Approach on Romanian Wines

Wine geographical traceability is an important topic in the context of wine authentication and for that, many researchers worldwide have addressed this subject by developing different methodologies based on multivariate analysis of natural chemical composition data (inorganic or organic parameters) and isotopic signature. The goal of this work was to assess the potential of elemental composition and strontium isotope ratio (⁸⁷Sr/⁸⁶Sr) of wines from important wine-producing regions in Romania, located in relatively small geographical areas, in order to highlight reliable markers for wine geographical origin discrimination. Elemental profile determinations were performed by ICP-MS, GFAAS, and FAAS techniques after microwave acid digestion of the wine samples. The ⁸⁷Sr/⁸⁶Sr isotope ratio of the resulted extracts was determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS), after separating strontium and rubidium using cation-exchange chromatography with Dowex 50W-X8 resin and the complexation ability of the carboxylic acid EDTA. The variation of elemental composition (Ga, Sr, and Al), Ca/Sr ratio, and the ⁸⁷Sr/⁸⁶Sr ratio of the investigated wine clearly demonstrated that these variables are suitable tracers for wine geographic origin determination. The proposed methodology allowed a 100 % successful classification of wines according to the region of provenance.     

Fingerprint and authenticity roasted coffees by <Superscript>1</Superscript>H-NMR: the Brazilian coffee case

With globalization, it has become necessary to adopt policies to regulate the coffee market, addressing problems including the authenticity and traceability of products. It is therefore important to establish methodologies that can help to safeguard the interests of producer countries and add value to products. For this purpose, the use of NMR combined with multivariate statistical procedures can be an attractive option. The aim of this study was to develop a fast and effective technique, using ¹H NMR coupled with multivariate statistics, to create a fingerprint of roasted coffees, distinguishing them according to the main Brazilian producer regions. Several compounds suitable for differentiating roasted coffees were identified in the fingerprint. Discriminant analysis revealed good distinction among the samples. The compounds catechol, trigonelline, caffeine, and n-methylpyridine were most important for the differentiation. The findings should assist coffee-producing countries in adopting measures to protect their markets and to add value to coffee products.     

太子参提取物抗氧化能力的比较研究

以柘荣太子参为原料,研究不同浓度乙醇的提取物及初步纯化物的抗氧化能力,通过体外模拟消化明确主要抗氧化成分在胃肠消化过程中的稳定性和抗氧化能力,并对主要成分进行初步鉴定。结果表明,70%乙醇粗提物抗氧化性较好,其经大孔树脂D101富集纯化后30%乙醇的洗脱物（X30）具有更好的抗氧化能力;皂苷和黄酮对抗氧化具有决定性作用,在胃肠消化过程中黄酮的稳定性好,X30在胃肠消化过程中仍具有较好的抗氧化性;皂苷类主要有sublateriol C和laetiposide F,黄酮类化合物主要包括 6,8-Di-C-beta-D-arabinopyranosylapigenin、apigenin 8-C-[xylosyl-（1->2）-galactoside]、isovitexin 2″-O-（6′″-（E）-p-coumaroyl）glucoside、木犀草素等。     

The Comparison of Cinnamomi Cortex and <Emphasis Type="Italic">Cinnamomum burmannii</Emphasis> Blume Using <Superscript>1</Superscript>H NMR and GC-MS Combined with Multivariate Data Analysis

Cinnamomi Cortex (CC, rougui) is the stripped trunk bark of Cinnamomum cassia Presl (CCP) and commonly is used to treat dyspepsia, gastritis, blood circulation disturbances, and inflammatory diseases. However, Cinnamomum burmannii Blume (CBB), an edible ingredient in food from a different Cinnamomum, sometimes replaces CC due to their similar functions and appearance. To identify and distinguish CC from CBB, we investigated the metabolite differences in polar and non-polar extracts of these species by high-resolution ¹H nuclear magnetic resonance (¹H NMR) spectroscopy and gas chromatography–mass spectrometry (GC-MS) combined with multivariate statistical analyses. The results showed a significantly higher separation in GC-MS analysis (non-polar extracts) than ¹H NMR analysis (polar extracts). One-way ANOVA revealed that polar extracts (acetate, α-glucose, sucrose, glycerol, fructose) and non-polar extracts (trans-cinnamaldehyde, α-copaene, δ-cadinene, 2-methoxycinnamaldehyde, (?)-calamenene, α-muurolene, γ-muurolene, α-calacorene, cubenol and α-muurolol) contributed greatly to the comparison of CC and CBB. These results indicate that the ¹H NMR- and GC-MS-based metabolomic approach can effectively differentiate the phytochemical compositions among different species in plants, which in turn could identify important metabolites with known pharmacological activity.     

Rapid Assessment of Fish Freshness and Quality by <Superscript>1</Superscript>H HR-MAS NMR Spectroscopy

A new analytical method that allows the rapid assessment of fish freshness and quality is presented. The method is based on ¹H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy and allows the rapid determination of two well-established indicators of fish freshness and quality: the K value and the trimethylamine nitrogen (TMA-N) content. The method is demonstrated on four different species of fish (sea bream, sea bass, trout, and red mullet) stored on ice at 0 °C. The results obtained are in agreement with more cumbersome methods classically used to determine the K value and the TMA-N concentration. The main advantage of the ¹H HR-MAS NMR approach is to allow a direct measurement of these two parameters directly on unprocessed fish sample without using any preliminary extraction. The total analysis time, including sample preparation, is of the order of 40 min per sample.     

Characterization of <Emphasis Type="Italic">Ficus sycomorus</Emphasis> tannin using ATR-FT MIR,MALDI-TOF MS and <Superscript>13</Superscript>C NMR methods

The Ficus sycomorus bark tannin was extracted and characterized using Attenuated Total Reflectance Fourier Transform Middle Infrared (ATR-FT MIR) spectra in the 1800 and 600 cm^?1 range, Matrix Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry (MALDI-TOF MS) and Carbon-13 Nuclear Magnetic Resonance (¹³C NMR) spectroscopy methods. Ficus sycomorus species have a very high percentage (46%) yield of tannin. These three characterization methods have shown that the Ficus sycomorus bark tannin is condensed and particularly a procyanidin type. It is composed of quercetin, apigenin, fisetinidin, catechin, gallocatechin, chalcone, radicinin, catechin gallate units with the presence of carbohydrates, quinone and gallic acid residues. The analysis results revealed that quercetin are the major constituents of Ficus sycomorus bark tannin. This procyanidin type tannin can give good wood adhesives.     

Physical,mechanical and biological properties of thermo-mechanically densified and thermally modified timber using the Vacu<Superscript>3</Superscript>-process

Densification and thermal modification change wood properties in different ways depending on the treatment conditions and the wood species. In the presented investigations, densification and thermal modification were applied consecutively. The primary objective of this treatment combination was the compensation of reduced mechanical properties due to the thermal modification by densification. The combined processes were applied to five European wood species: poplar (Populus nigra L.), beech (Fagus sylvatica L.), Norway spruce (Picea abies Karst.), English oak (Quercus robur L.) and European ash (Fraxinus excelsior L.). Depending on the mean density of the species, a thermo-mechanical densification of 43 or 50% was imposed to improve mechanical strength parallel to the grain. Subsequently, the densified material was thermally modified in the so-called Vacu³-process at 230 °C and 20 or 80% vacuum and at 240 °C and 20% vacuum. The thermal modification resulted in changing wood colour, mechanical strength, hardness, dimensional stability and durability. All the wood modification processes were carried out at industrial scale after pre-tests at laboratory scale. The modified material was characterized regarding flexural properties, static and dynamic hardness, structural integrity, abrasion resistance, moisture dynamics, dimensional stability, and durability against white, brown and soft rot fungi. In summary, the test results showed that the consecutive application of thermo-mechanical densification and thermal modification leads to significantly improved durability whilst mechanical properties at least for beech, ash and poplar remained and the material is dimensionally stable.     

4种茶叶水提物及茶多酚的体外抗氧化性能研究

采用水提法对红茶、乌龙茶、绿茶和茉莉花茶进行提取,并对抽提物中总酚含量和各个儿茶素单体含量进行测定,通过常见的3种抗氧化能力测试方法,即DPPH法、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐[(2,2-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid)diammonium salt,ABTS)]法及铁离子还原/抗氧化能力(ferric ion reducing antioxidant power,FRAP)法对4种茶叶水提物的体外抗氧化能力进行评价,同时比较茶多酚和VC的抗氧化活性。结果表明:4种茶叶水提物均有很强的体外抗氧化活性,绿茶、茉莉花茶、乌龙茶的DPPH法及FRAP法抗氧化活性测试结果优于红茶,红茶的ABTS+·清除率略高于其他3种茶。相关性分析结果显示儿茶素总量、总酚含量、没食子儿茶素(gallocatechin,GC)、表没食子儿茶素(epigallocatechin,EGC)、表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)、表儿茶素没食子酸酯(epicatechin gallate,ECG)含量和DPPH法、FRAP法结果呈现正相关,而与ABTS法结果呈现负相关。此外,试验结果表明茶多酚的抗氧化能力高于V_C。     

Use of the Oxygen Radical Absorbance Capacity (ORAC) Assay to Predict the Capacity of Mango (<Emphasis Type=Italic>Mangifera indica</Emphasis> L.) By-Products to Inhibit Meat Protein Oxidation

The potential activity of mango by-products to inhibit the peroxyl radical-mediated oxidation of tryptophan residues (Trp) of myofibrillar proteins (MP) was studied. Extracts of seeds, peels and pulps were studied in terms of their antioxidant activity, assessed by the oxygen radical absorbance capacity (ORAC) assay employing fluorescein and pyrogallol red as probes (ORAC-FL and ORAC-PGR, respectively). The effect of the extracts of mango by-products on the oxidation of Trp was evaluated by fluorescence spectroscopy. Data obtained employing the ORAC-FL assay showed a low discrimination of the antioxidant activity of the samples (Peel ≈ Seed > Pulp). However, employing the ORAC-PGR assay it was possible to differentiate the antioxidant activity of the samples (Seed > Peel >> Pulp). Extracts obtained from mango seed, peel, and pulp protected Trp of MP when the latter was exposed to AAPH (2,2′-azo-bis(2-amidinopropane) dihydrochloride)-derived free radicals. Such effect was in good agreement with the ORAC-PGR data, showing that this assay could be employed to predict the protection of Trp residues of MP.     

Chemometric Analysis of <Superscript>1</Superscript>H NMR Fingerprints of <Emphasis Type="Italic">Coffea arabica</Emphasis> Green Bean Extracts Cultivated under Different Planting Densities

High planting density has been used to increase coffee production but there are few studies related to the variations it provokes in metabolite compositions. The use of ¹H NMR data associated with chemometric techniques allows the determination of metabolic fingerprints and verification of metabolic changes when coffee is subjected to high planting densities. The aim of this work is to investigate ¹H NMR spectral data of green bean extracts of Coffea arabica cv. IAPAR 59 grown in a square pattern at two planting densities, 6000 and 10,000 plants ha^?1. Thirty extracts were obtained using a simplex centroid design with four solvents (ethanol, acetone, dichloromethane, and hexane). The lyophilized extracts were dissolved in DMSO-d₆ to obtain the ¹H NMR spectra. The spectral data were analyzed with principal component (PCA) and cluster analyses (CA). Significant differences between ethanolic and non-ethanolic extracts were found by PCA. Only the ethanolic mean spectrum showed characteristic chemical shifts of sugars and trigonelline. Acetone extracts were separated by cluster analysis.     

Biochemical,physical and sensory quality of ice-stored Atlantic cod (<Emphasis Type="Italic">Gadus morhua</Emphasis>) as affected by pre-slaughter stress,percussion stunning and AQUI-S<Superscript>™</Superscript> anaesthesia

Biochemical, physical and sensory quality of farmed Atlantic cod subjected to percussion stunning (control), anaesthesia (AQUI-S^™) and excessive exercise (30 min chasing before slaughter, ‘stressed’) were analysed after 7 days of ice storage. The white muscle energy status (initial pH, muscle twitches and high-energy phosphates) revealed that the fish were truly representatives of rested (percussion stunned and anaesthetised) and stressed cod. Sensory evaluation showed that the fillets of cod exposed to percussion stunning and AQUI-S^™ anaesthesia prior slaughter had slightly higher whiteness scores, and that the fillets of AQUI-S^™ anaesthetised cod had slightly shinier surfaces than the fillets of cod exposed to pre-slaughter stress. Furthermore, fillets of anaesthetised (AQUI-S^™) cod had significantly higher inosine monophosphate (IMP) contents and lower K-values than fillets of cod exposed to pre-slaughter stress, after 7 days of ice storage. Pre-slaughter stress did to some extent affect fillet colour immediately after killing and after ice storage. Otherwise, no significant effects of stress were observed with regard to biochemical, physical or sensory quality (ultimate pH, water content, drip loss, water holding capacity, texture and gaping) of farmed Atlantic cod.     

21种蜂花粉水提取物抗氧化活性的比较研究

采用O2-·、·OH、DPPH·等自由基生成体系和铁离子还原/抗氧化力测定法(FRAP法)对21种蜂花粉水提取物清除自由基的能力和总抗氧化活性进行了比较研究.结果表明对·OH清除能力最强的是五味子.山茶、油莱、枸杞、苦菜、养麦等次之,玉米、樱花和玫瑰最弱.对O2-·的清除能力以樱桃、山楂和野菊花较强,养麦和五味子最弱.对DPPH·的清除量以苦菜最高,其次是梨花、玉米、山茶、桂花、枇杷、西瓜等,白莲和荞麦的清除量最低.总抗氧化活性以五味子最强,黄芪和樱花较强,枇杷、养麦、白莲较弱.     

“复方抗氧化制剂”抗氧化能力的研究

探讨"复方抗氧化制剂"对大鼠骨骼肌抗氧化能力的影响,以期为开发保健饮料提供一定的参考作用。选取42只雄性Wistar大鼠,随机分为对照组与实验组,8周后分别于安静状态、定量负荷运动后、力竭运动后、力竭运动24 h后测试大鼠骨骼肌总抗氧能力、MDA含量、GSH含量。结果表明,安静状态下、定量负荷运动后、力竭运动后、力竭运动24 h后,实验组大鼠骨骼肌中总抗活性氧能力明显高于对照组(P<0.05),GSH含量明显高于对照组(P<0.05);安静状态下、定量负荷运动后、力竭运动后,实验组大鼠骨骼肌中MDA含量明显低于对照组(P<0.05)。"复方抗氧化制剂"能够提高大鼠在不同功能状态下骨骼肌中抗氧化能力。