1,721,006 research outputs found
IRMS, SNIF-NMR and proton NMR in wine analysis
Full text linkWine is an important element of world food industry; last year the wine production in EU was over 180 million hl (over 60% share of the world) and contributed over € 7 billion to EU trade balance. Such large markets always attract fraudulency and wine is no exception: in 2012 to 2015 counterfeit goods have cost € 59 billion, of these spirits and wine being € 2.7 billion. Therefore, effective control of such adulterations requires use of robust and reliable analytical methods for authentication of wines. One of these is isotope ratio mass spectrometry (IRMS), via which it is possible to measure ratios of nature stable isotopes of carbon, hydrogen and oxygen in wine. They depend on the origin of the compounds containing them and, therefore, allow for determining geographical origin of the samples and addition of water and exogenous sugar. Another approach is Site-specific Natural Isotopic Fractionation Nuclear Magnetic Resonance Spectroscopy (SNIF-NMR). By this method, the site-specific D/H isotope ratio in methylic and methylenic sites of ethanol is measured, and the values aid in determining the origin of ethyl alcohol in wine. In 1990s European Commission and International Organization of Vine and Wine (OIV) has adopted this method as a certified official method for analysis of wines. It is the only method based on NMR recognized as official standard. IRMS and SNIF-NMR methods are robust and reliable, but have some disadvantages, such as use of expensive standards, prolonged sample preparation, expensive equipment maintenance; also, the analysis is destructive in many cases. Over the recent years, a new approach for wine analysis emerged: proton NMR spectroscopy, which can be used for either targeted analysis, or non-targeted profiling. Compared to classical methods, proton NMR requires less sample preparation, less time to record the spectrum and has cheaper equipment maintenance costs. However, it has not yet been officially approved for food authentication
Caratterizzazione delle mele italiane a polpa rossa: approfondimenti NMR su fattori varietali, conservazione e geografici
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Characterization of Italian, red-fleshed apples: NMR insights into varietal, storage, and geographic factors
No full textNuclear magnetic resonance applications in fermented foods and plant-based beverages: challenges and opportunities
Full text linkCurrently, there has been a growing interest in fermented foods and plant-based beverages (PBBs) by the consumers because of the benefits they provide to human health or due to restrictions in the diet associated to some pathologies or personal choices. Nuclear magnetic resonance (NMR) is a versatile technique that presents many advantages for the identification and quantification of metabolites in food with a variety of one- and two-dimensional experiments. This review delves into the current applications of NMR in the fields of fermented foods and PBBs. The interest from researchers in the analysis of fermented foods by NMR in the recent literature mainly focused on three main sub-areas: characterization of exopolysaccharides (EPS) and their functional, and rheological properties; metabolomics to find discriminant markers during and after the process of fermentation for the optimization of the productive process or development of products; and characterization of traditional and novel foods. However, the area of plant-based beverages studies by NMR presented a remarkable literature gap. The opportunities for future investigations concerning food authentication, traceability, and functional food development, among others, are presented
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
NMR profiling of grape musts from some Italian regions
Full text linkWith wine fraud, being a widespread problem [1], the need for more sophisticated and precise analytical methods of its detection remains ever persistent. Nuclear magnetic resonance (NMR) spectroscopy has been widely used for analysis of wine in recent years [2,3], but wine musts were much less studied; in fact, only one paper dealt with the NMR spectra of actual musts [4]. Difficulties arise mostly because grape musts are “live” objects, which undergo rapid fermentation at room temperature, if not inhibited either by freezing or chemical preservative; but even such measures are not sufficient to halt it completely [5].
We have investigated over 300 samples of grape must from 17 of 20 different Italian regions using 1H NMR spectroscopy with water signal suppression, postprocessing in the MatLab software with dynamic alignment [6] and optimized binning [7] to alleviate the effect of fermentation on the chemical shifts of mobile protons. After that, multivariate statistics was performed with techniques such as PCA, PLS-DA and OPLS-DA with respect to various group parameters such as regions, vitivinicultural zones, harvest periods and grape varieties. Advantages and drawbacks of each method were addresse
1H NMR profiling and chemometric analysis for ripening and production characterization of Grana Padano cheese
Full text linkGrana Padano (GP) cheese is a renowned PDO Italian cheese whose nutritional characteristics and market price are influenced by the ripening stage. In this work, it was demonstrated that the combined use of untargeted 1H NMR profiling and chemometric analysis can be used as a powerful tool to quantitatively characterize GP ripening and production, focusing on both aqueous and lipid fractions. An initial exploratory analysis revealed substantial variations in the aqueous fraction attributable to aging time, year and season of production. Multivariate analysis was adopted to show these differences, mainly attributable to amino acids. In contrast, the lipid fraction analysis highlighted the impact of production season on fatty acid unsaturation, influenced by feed variations. As regards the production process, this study focuses on the variations induced by bactofugation. In this respect, the aqueous fraction was found to be extensively influenced by this centrifugation step, affecting compounds crucial to organoleptic characteristic
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