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geographic origin (6)

This research is by the same French team, who reported using elemental strontium and strontium isotopes as markers for geographic origin and authenticity of Bordeaux wines, which was reported as a 27 April 2019 News item. In this research, lead (Pb) concentrations and Pb isotope ratios of 43 authentic Bordeaux wines from prestigious châteaux and 14 suspicious Bordeaux origin were determined to evaluate their potential as markers for authenticity and geographical origin. Total Pb concentrations in Bordeaux wines have drastically decreased over the past 50 years corresponding to changes in environmental lead concentrations with a clear shift of isotopic signatures towards geological values. The Pb isotopic ratios determined in both sets of samples clearly demonstrated that the suspicious Bordeaux wines displayed Pb isotopic signatures statistically distinctive from those obtained for authentic Bordeaux wines. Three isotopic ratio signatures using the geological and environmental Pb isotopes data that characterise European and Asian sources were used to give a non-ambiguous discrimination between authentic Pauillac AOC and the counterfeit wines.   

3436675196?profile=RESIZE_710x Read the abstract here

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Bordeaux wines are highly valued and sought after, and hence vulnerable to counterfeiting. French reseachers have used strontium concentration and strontium isotope ratios as markers for Bordeaux wine geographic origin and authenticity. Forty three authentic Bordeaux wines were collected from the world’s most prestigious Bordeaux châteaux. The Sr elemental composition and 87Sr/86Sr ratio were determined on these authentic wines. The results demonstrated relatively small variabilities for 87Sr/86Sr ratio and Sr concentrations in the authentic Bordeaux wines, which can be used with reasonable certainty to identify regional Bordeaux wineries and distinguish them from counterfeit wines.

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The Olive Oil Marketing Regulation requires that olive oils of mixed origin have to be designated as either EU and/or non-EU origin. In this study 2H/1H, 13C/12C and 18O/16O ratios were analysed in bulk olive oils using  isotope ratio mass spectrometry (IRMS) as well as 13C/12C and 2H/1H in the four main fatty acids (linoleic, oleic, palmitic and stearic acids) using IRMS coupled with GC (gas chromatography). The isotopic composition of olive oils was successfully used to distinguish samples originating in the two areas. When bulk data were combined with fatty acid isotopic data the differentiation power of the method was improved. The improvement is due to the specific isotopic fingerprint of the individual countries making up the EU and non-EU samples. 

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Chinese researchers have developed an integrated approach combining HPLC/DAD, GC/MS, near infrared (NIR) spectroscopy, and chemometrics  to geographically discriminate saffron samples from Iran and China. Using a dataset based on 98 samples of saffron, the saffron compounds picrocrocin and two types of crocins were found to be the discriminating markers, and the Chinese samples had higher contents of safranal and picrocrocin but lower cis-crocin 3Gg, kaempferol-3-O-sophoroside and isophorone. 

 Furthermore, an NIR method was successfully established to rapidly distinguish the Chinese and Iranian samples. The relationship between an ISO standard and the contents of the chemical indices was also studied. The results indicated that the ISO standard should be revised, especially for analysing safranal.

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Marketing of cocoa and chocolate products made from single origin cocoa is becoming more popular. However, a reliable analytical method able to verify the geographical origin of cocoa is lacking. The potential of HR MAS 1H NMR (Magic-angle spinning NMR in solid state) on cocoa powder combined with chemometrics for metabolic profiling was assessed for the geographical origins of 60 fermented and dried cocoa beans of 23 different cocoa producing countries from the three major crop-growing areas (Africa, Central/South America, Asia/Oceania) was evaluated. The same samples were also subjected to extraction and analysis with liquid solution 1H NMR. The same metabolites were determined by both methods apart from the additional determination of of cocoa lipids by HR MAS 1H NMR, which were lost in the extraction for liquid 1H NMR. HR MAS 1H NMR  gave better discrimination in the verification of geographical origin.

Read the abstract at: NMR determination of cocoa origin

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A study has been completed to look at the ratio of stable isotopes of  δ18O, (D/H)I, (D/H)II, δ13C, δ15N and 87Sr/86Sr moving from the soil, through the cultivation of grapes and their preparation at different stages into wine.  The isotopic ratio of 87Sr/86Sr does not vary significantly from grape to wine, and δ15N has been proposed as further isotopic marker for the geographical characterisation of grape products.

The paper in Food Chemistry by Caterina Durante et al is in press, but the abstract can be read at http://www.sciencedirect.com/science/article/pii/S0308814616306318

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