Stable Isotope Ratios of Herbs and Spices Commonly Used as Herbal Infusions in the Italian Market.

Stable isotope ratio analysis has been widely used for traceability and authenticity purposes in relation to various food commodities, but only in a limited number of herb and spice species. This study explored the stable isotope ratios of carbon, nitrogen, sulfur, oxygen, and hydrogen (δ13C, δ15N, δ34S, δ18O, and δ2H) of 119 herbs and spices belonging to 116 plant species and 57 plant families collected from the Italian market for the first time. The characteristic value ranges of δ13C, δ15N, δ34S, δ18O, and δ2H of the herbs and spices went from -31.0 to -11.6, -4.7 to 12.0, -5.0 to 22.0, 14.7 to 46.0, and -158 to -12‰, respectively. The isotopic profiles within and between common botanical families and their similarity/dissimilarity between herbs and spices belonging to the common botanical families are also discussed here. The results of this exploratory work highlight the possibility of characterizing herbs and spices and suggest widening the scope of the survey through more extensive sampling and focusing on specific plant species.

Influence of Fermentation Water on Stable Isotopic D/H Ratios of Alcohol Obtained from Concentrated Grape Must.

According to Organisation Internationale de la vigne et du vin (OIV) standards, when analysing the stable isotope ratio of deuterium to hydrogen D/H at the methyl (I) and methylene (II) site of ethanol from concentrated must, a dilution with tap water is needed in order to carry out the alcoholic fermentation. This dilution causes a partial transfer of water hydrogens to the sugar, and this affects the (D/H)I and (D/H)II isotopic values of ethanol, which need to be normalised through specific equations based on the analysis of water δ18O or δ2H. The aim of this study was to evaluate the effectiveness and correctness of these equations experimentally. Grape, cane, and beet sugar, as well as grape must were diluted with water with increasing H and O stable isotope ratios, fermented, and analysed. SNIF-NMR and IRMS techniques were applied following the respective OIV methods. The equations based on the δ2H analysis of the diluted sugar/must solutions proved to be reliable in all the cases, although it is not an OIV standard. When using the equations based on the values of δ18O of the diluted solution, data normalisation was reliable only in cases where the water used for dilution had not undergone isotopic fractionation due, for example, to evaporation. In these cases, δ2H should be analysed.

δ34 S for tracing the origin of cheese and detecting its authenticity.

Casein δ34 S of 725 samples of cheese from all over the world were measured using IRMS. δ34 S alone made it possible to establish characteristic ranges of values for two types of Italian cheese (Grana Padano PDO and Parmigiano Reggiano PDO) and for the different regions and provinces of both the Grana Padano PDO and the Parmigiano Reggiano PDO zones. Moreover, δ34 S of PDO Italian samples were compared to both Italian (not PDO) and foreign competitive cheese samples. In all the cases, sulfur isotopic ratio analysis was a powerful tool to fix characteristic ranges of values for cheeses coming from different countries and to improve the information given by other isotopic parameters.

Determination of the 13C/12C Carbon Isotope Ratio in Carbonates and Bicarbonates by 13C NMR Spectroscopy.

This paper is the first study focused on the innovative application of 13C NMR (nuclear magnetic resonance) spectroscopy to determine the bulk 13C/12C carbon isotope ratio, at natural abundance, in inorganic carbonates and bicarbonates. In the past, 13C NMR spectroscopy (irm-13C NMR) was mainly used to measure isotope ratio monitoring with the potential of conducting 13C position-specific isotope analysis of organic molecules with high precision. The reliability of the newly developed methodology for the determination of stable carbon isotope ratio was evaluated in comparison with the method chosen in the past for these measurements, i.e., isotope ratio mass spectrometry (IRMS), with very encouraging results. We determined the 13C/12C ratio of carbonates and bicarbonates (∼50-100 mg) with a precision on the order of 1‰ in the presence of a relaxation agent, such as Cr(acac)3, and CH313COONa as an internal standard. The method was first applied to soluble inorganic carbonates and bicarbonates and then extended to insoluble carbonates by converting them to Na2CO3, following a simple procedure and without observing isotopic fractionation. Here, we demonstrate that 13C NMR spectroscopy can also be successfully adopted to characterize the 13C/12C isotope ratio in inorganic carbonates and bicarbonates with applications in different fields, such as cultural heritage and geological studies.

Hydrogen and oxygen stable isotope fractionation in body fluid compartments of dairy cattle according to season, farm, breed, and reproductive stage.

Environmental temperature affects water turnover and isotope fractionation by causing water evaporation from the body in mammals. This may lead to rearrangement of the water stable isotope equilibrium in body fluids. We propose an approach to detect possible variations in the isotope ratio in different body fluids on the basis of different homoeothermic adaptations in varying reproductive stages. Three different reproductive stages (pregnant heifer, primiparous lactating cow, and pluriparous lactating cow) of two dairy cattle breeds (Italian Friesian and Modenese) were studied in winter and summer. Blood plasma, urine, faecal water, and milk were sampled and the isotope ratios of H (2H/1H) and O (18O/16O) were determined. Deuterium excess and isotope-fractionation factors were calculated for each passage from plasma to faeces, urine and milk. The effects of the season, reproductive stages and breed on δ2H and δ18O were significant in all the fluids, with few exceptions. Deuterium excess was affected by season in all the analysed fluids. The correlations between water isotope measurements in bovine body fluids ranged between 0.6936 (urine-milk) and 0.7848 (urine-plasma) for δ2H, and between 0.8705 (urine-milk) and 0.9602 (plasma-milk) for δ18O. The increase in both isotopic δ values in all body fluids during summer is representative of a condition in which fractionation took place as a consequence of a different ratio between ingested and excreted water, which leads to an increased presence of the heavy isotopes. The different body water turnover between adult lactating cattle and non-lactating heifers was confirmed by the higher isotopic δ for the latter, with a shift in the isotopic equilibrium towards values more distant from those of drinking water.