1,720,996 research outputs found
Multiple Assignment Recovered Analysis (MARA) NMR for a Direct Food Labeling: the Case Study of Olive Oils
No full textThe multiple assignment recovered analysis (MARA) on nuclear magnetic resonance (NMR) spectra is here presented with the aim to provide the quantitative label of chemical mixtures such as foodstuff. The method takes advantage from the multiple NMR signals generated by any chemical; these will be all proportional to the concentration of the parent compound. In a well-known system, the selection of many integration regions enables the development of simple relationships fulfilled just by specific quantitative values of the expected components. As long as the number of equations is bigger than the known quantitative variables, MARA-NMR best-fitting algorithm will be suitably designed to output trustworthy and robust results. This is definitely demonstrated for the extra-virgin olive oil (EVOO) taken as case study: MARA-NMR showed consistency with traditional analytical measurements over 30 specimens recording satisfactory repeatability. The minimization procedure is applied by tuning the quantitative variables; these are affecting the function ρ which represents the experimental lapse from the corresponding theoretical dataset. MARA-NMR is an effective, innovative, and quick method for food labeling; unlike other analytical techniques, it is self-consistent smoothing out random instrumental outliers or unpredictable anomalies. MARA is customized in order to be versatile paving the way for new updated, extended, and refined labeling protocols and also for the extension of this approach on the study of whichever matrix
NMR Detection of specific minor components separated by complex matrices such as extra-virgin olive oil (EVOO)
No full textDo vine cropping and breeding practices affect the biogenic amines' content of produced wines?
No full textBiogenic amines (BAs) are nitrogen compounds commonly found in wine and some of them are commonly associated with poor sanitary conditions of the grapes. The main BAs of the wine are histamine, tyramine, putrescine, cadaverine, spermine and spermidine. They can be associated with toxic effects in humans and many secondary BAs are believed to be cancerogenic compounds. To assure high levels of food quality and safety, this study aims to investigate the effects of different vineyard management practices on the BA concentrations in experimental Italian red wines produced in the same region from different grape varieties and under identical vinification procedures. The impact of two different horticultural cropping methods and three breeding techniques was considered. The quantification of eight BAs in experimental red wines was carried out by ultra-high performance liquid chromatography (UHPLC) coupled to a photodiode array (PDA) detector on dansylated amines. The results of the multivariate analysis evidenced that a correlation does exist between the BA content in wine and the relative vine management
Determination of 1,2/1,3-diglycerides in Sicilian extra-virgin olive oils by 1H-NMR over a one-year storage period
No full textThis study is aimed to monitor by 1H NMR spectroscopy the effect of a 12-month storage period on the 1,2-diglycerides over 1,3-diglycerides ratio for five mono-cultivar ‘extra virgin olive oils’ (EVOO) (Arbequina, Arbosana, Cerasuola, Nocellara and FS17) and one blend of two different cultivars (Nocellara + Biancolilla) preserved in the dark and at room temperature. These quantifications, at 500 MHz, are readily extracted through a specific and original integration difference method. Albeit it was known that the isomerisation rate is affected by the free acidity, we here demonstrate that it also depends on the presence of specific macromolecules (lipases), indeed, different EVOO cultivars with similar free acidity, show different isomerisation rate. Our results are consistent with similar diglyceride monitoring performed on Greek and Spanish EVOOs by 31P NMR
Food to Life - IV International Conference on Foodomics - 8-9-October-2015 - Cesena - Italy
No full textMetabolite Determination of typical food in mediterranean diet by HR-MAS NM
An in-depth study of the volatile variability of chinotto (Citrus myrtifolia Raf.) induced by the extraction procedure
No full textA variety of extraction methodologies were applied to chinotto (Citrus myrtifolia) fruits from Sicily, along with sensory and chemical analyses. By gas chromatographic techniques, either in monodimensional (GC-FID, GC–MS) or in multidimensional (MDGC) fashion, it was established how the isolation procedure affected the volatile fingerprint of such fruit. In general, limonene, linalyl acetate, myrcene, β-pinene, α-pinene, (E)-β-ocimene, linalool and geranyl acetate resulted to be the predominant volatiles. However, although revealed at lower levels, other compounds, such as trans-linalool oxide, perilla alcohol, trans-limonene oxide, may be responsible for peculiar olfactory notes. Compounds such as linalool, myrcene, β-pinene, octanal, decanal, and geranyl and perillyl acetates were selectively extracted by blending plus the addition of solvents. (E)-β-Ocimene and nootkatone were considerably expressed in hand-squeezed and solvent-extracted samples, respectively. On the other hand, linalyl acetate was the most abundant compound in samples extracted by solvent. Concerning the sensory evaluations, odor characters varied depending on the oil extraction methodology. Indeed, the flowery and citrus notes were perceived in all samples by the majority of panelists; conversely, the minty attribute was the one least smelled in five out of six samples. Enantio-MDGC analysis highlighted seven chiral pairs, with the following enantiomeric ratios: (−)/ (+) limonene (1.8/98.2), (−)/(+) linalyl acetate (99.4/0.6), (+)/(−) β-pinene (99.8/0.2), (−)/(+) linalool (5.5/94.5), (+)/(−) terpinen-4-ol (48.9/51.1), (−)/(+) α-pinene (22.3/77.7) and (−)/(+) α-terpineol (20.5/79.5)
15th Euro Fed Lipid Congress 27-30 August 2017- Uppsala- Swden " Oil, Fats and Lipids: New Technologies and Applications for a Healthier Life
No full textQuick unreferenced NMR quantification of Squalene in vegetable oils
Full text linkWe present here a simple method for the rapid quantification of squalene in vegetable oils by NMR (Nuclear Magnetic Resonance). The method was validated by adding internal standards to several vegetable oil samples. Quantification was accomplished by exploiting the characteristic resolved signal of terminal methyl groups at 1.67 ppm, which allowed squalene quantification regardless of the hydrophobic matrix. Theoretical principles are fulfilled by the method and, despite the general belief that NMR displays intrinsic low sensitivity, acceptable accuracy (<4%) and reproducibility (<6%) can be reached when squalene is over 2000 ppm, even in “worst case scenarios.” This method may be useful in the continuing efforts to rapidly generate accurate and complete quantitative data suitable for inclusion in the identification labels of vegetable oil products. Practical applications: Unreferenced and accurate quantification of squalene in vegetable oils, was validated here by the analysis of several1H-NMR spectra of vegetable oils and of standard doped samples. Moreover, we found that squalene can affect the NMR spectra of other quantifiable species. These data may be useful to produce more accurate and precise analyses of vegetable oil using their1H-NMR profiles. Collectively, our data indicate that quantification of squalene in vegetable oils can be easily accomplished by1H-NMR, opening new potentialities in NMR-based fat analysis. The ability of squalene to alter NMR spectra should be taken into account, particularly in oils with a high squalene content, such as Sicilian olive oils
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