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Special Issue "Isotopic Techniques for Food Science"

A special issue of Molecules (ISSN 1420-3049).

Deadline for manuscript submissions: closed (15 July 2020) | Viewed by 15711

Special Issue Editors

Prof. Dr. Nives Ogrinc
E-Mail Website
Guest Editor
Jožef Stefan Institute, Department of Environmental Sciences, Jamova 39 1000, Ljubljana
Interests: food chemistry; isotope analysis; geographic variability; authenticity
Dr. Federica Camin
E-Mail Website
Guest Editor
Fondazione Edmund Mach, Research and Innovation Centre, Department of Food Quality and Nutrition, Traceability Unit, via Mach 1, 38010, San Michele all’Adige, Trento, Italy
Interests: stable isotope ratios; food; authenticity; origin traceability; fraud; mass spectrometry; compound-specific analysis; databases; modeling

Special Issue Information

Dear Colleagues,

Today, the analytical verification of food safety and quality together with authenticity and traceability plays a central role in food analysis, and over the past few years, there has been a renewed effort towards the development of new, rapid, and accurate methods for verifying both quality and safety. Among the exploitable techniques, stable isotope ratio analysis (SIRA) has gained increasing importance for determining the authenticity of foods of animal and plant origin for both producers and control agencies. Furthermore, modern instruments can produce large complex datasets, which have, in parallel, led to the development of sophisticated chemometric methods for their evaluation, and the development of appropriate models with the ability to discriminate the authenticity and origin of food products.

This Special Issue of Molecules seeks to explore emerging topics and trends in isotopic techniques and their application to food science—from instrumentation, measurement, and data analysis to novel applications.

Prof. Dr. Nives Ogrinc
Dr. Federica Camin
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2300 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • isotopic techniques
  • light and heavy elements
  • mass spectrometry
  • NMR spectroscopy
  • authenticity
  • traceability
  • modeling

Published Papers (12 papers)

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Editorial

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Editorial
Special Issue “Isotopic Techniques for Food Science”
Molecules 2021, 26(1), 134; https://doi.org/10.3390/molecules26010134 - 30 Dec 2020
Viewed by 742
Abstract
Today, the analytical verification of food safety and quality together with authenticity and traceability plays a central role in food analysis [...] Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)

Research

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Article
Fatty Acid Composition of Cosmetic Argan Oil: Provenience and Authenticity Criteria
Molecules 2020, 25(18), 4080; https://doi.org/10.3390/molecules25184080 - 07 Sep 2020
Cited by 7 | Viewed by 1331
Abstract
In this work, fatty-acid profiles, including trans fatty acids, in combination with chemometric tools, were applied as a determinant of purity (i.e., adulteration) and provenance (i.e., geographical origin) of cosmetic grade argan oil collected from different regions of Morocco in 2017. The fatty [...] Read more.
In this work, fatty-acid profiles, including trans fatty acids, in combination with chemometric tools, were applied as a determinant of purity (i.e., adulteration) and provenance (i.e., geographical origin) of cosmetic grade argan oil collected from different regions of Morocco in 2017. The fatty acid profiles obtained by gas chromatography (GC) showed that oleic acid (C18:1) is the most abundant fatty acid, followed by linoleic acid (C18:2) and palmitic acid (C16:0). The content of trans-oleic and trans-linoleic isomers was between 0.02% and 0.03%, while trans-linolenic isomers were between 0.06% and 0.09%. Discriminant analysis (DA) and orthogonal projection to latent structure—discriminant analysis (OPLS-DA) were performed to discriminate between argan oils from Essaouira, Taroudant, Tiznit, Chtouka-Aït Baha and Sidi Ifni. The correct classification rate was highest for argan oil from the Chtouka-Aït Baha province (90.0%) and the lowest for oils from the Sidi Ifni province (14.3%), with an overall correct classification rate of 51.6%. Pairwise comparison using OPLS-DA could predictably differentiate (≥0.92) between the geographical regions with the levels of stearic (C18:0) and arachidic (C20:0) fatty acids accounting for most of the variance. This study shows the feasibility of implementing authenticity criteria for argan oils by including limit values for trans-fatty acids and the ability to discern provenance using fatty acid profiling. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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Article
Milk Authentication: Stable Isotope Composition of Hydrogen and Oxygen in Milks and Their Constituents
Molecules 2020, 25(17), 4000; https://doi.org/10.3390/molecules25174000 - 02 Sep 2020
Cited by 4 | Viewed by 1079
Abstract
This paper summarises the isotopic characteristics, i.e., oxygen and hydrogen isotopes, of Slovenian milk and its major constituents: water, casein, and lactose. In parallel, the stable oxygen isotope ratios of cow, sheep, and goat’s milk were compared. Oxygen stable isotope ratios in milk [...] Read more.
This paper summarises the isotopic characteristics, i.e., oxygen and hydrogen isotopes, of Slovenian milk and its major constituents: water, casein, and lactose. In parallel, the stable oxygen isotope ratios of cow, sheep, and goat’s milk were compared. Oxygen stable isotope ratios in milk water show seasonal variability and are also 18O enriched in relation to animal drinking water. The δ18Owater values were higher in sheep and goat’s milk when compared to cow milk, reflecting the isotopic composition of drinking water source and the effect of differences in the animal’s thermoregulatory physiologies. The relationship between δ18Omilk and δ18Olactose is an indication that even at lower amounts (>7%) of added water to milk can be determined. This procedure once validated on an international scale could become a reference method for the determination of milk adulteration with water. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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Article
Feasibility of Casein to Record Stable Isotopic Variation of Cow Milk in New Zealand
Molecules 2020, 25(16), 3658; https://doi.org/10.3390/molecules25163658 - 11 Aug 2020
Cited by 4 | Viewed by 968
Abstract
Dairy products occupy a special place among foods in contributing to a major part of our nutritional requirements, while also being prone to fraud. Hence, the verification of the authenticity of dairy products is of prime importance. Multiple stable isotopic studies have been [...] Read more.
Dairy products occupy a special place among foods in contributing to a major part of our nutritional requirements, while also being prone to fraud. Hence, the verification of the authenticity of dairy products is of prime importance. Multiple stable isotopic studies have been undertaken that demonstrate the efficacy of this approach for the authentication of foodstuffs. However, the authentication of dairy products for geographic origin has been a challenge due to the complex interactions of geological and climatic drivers. This study applies stable isotope measurements of δ2H, δ18O, δ13C and δ15N values from casein to investigate the inherent geo-climatic variation across dairy farms from the South and North Islands of New Zealand. The stable isotopic ratios were measured for casein samples which had been separated from freeze-dried whole milk samples. As uniform feeding and fertilizer practices were applied throughout the sampling period, the subtropical (North Island) and temperate (South Island) climates were reflected in the variation of δ13C and δ15N. However, highly correlated δ2H and δ18O (r = 0.62, p = 6.64 × 10−10, α = 0.05) values did not differentiate climatic variation between Islands, but rather topographical locations. The highlight was the strong influence of δ15N towards explaining climatic variability, which could be important for further discussion. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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Article
Influence of Fermentation Water on Stable Isotopic D/H Ratios of Alcohol Obtained from Concentrated Grape Must
Molecules 2020, 25(14), 3139; https://doi.org/10.3390/molecules25143139 - 09 Jul 2020
Cited by 2 | Viewed by 747
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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Article
Validation of the 2H-SNIF NMR and IRMS Methods for Vinegar and Vinegar Analysis: An International Collaborative Study
Molecules 2020, 25(12), 2932; https://doi.org/10.3390/molecules25122932 - 25 Jun 2020
Cited by 4 | Viewed by 1349
Abstract
This paper presents the results of a collaborative study involving seven laboratories and concerning two samples of wine vinegar, one of apple vinegar and four of balsamic vinegar. The aim of the study was to define standard deviations of repeatability (sr) and reproducibility [...] Read more.
This paper presents the results of a collaborative study involving seven laboratories and concerning two samples of wine vinegar, one of apple vinegar and four of balsamic vinegar. The aim of the study was to define standard deviations of repeatability (sr) and reproducibility (sR) for vinegar and balsamic vinegar stable isotope ratios of H (D/H), C (δ13C) and O (δ18O), in order to establish them as fully recognized official standards. Acetic acid was extracted and subjected to (D/H)CH3 and δ13C analysis. δ18O analysis was performed on whole samples. The grape must solution remained after distillation of balsamic vinegar was fermented and the resulting ethanol was subjected to (D/H)I, (D/H)II, R and δ13C analysis. The sr and sR were 0.6 ppm and 1.1 ppm for (D/H)CH3, 0.14‰ and 0.25‰ for δ13C of acetic acid, 0.1‰ and 0.17‰ for δ18O of water, 0.19 ppm and 0.64 ppm for ethanol (D/H)I, 1.14 and 1.31 ppm for (D/H)II, 0.09 and 0.11‰ for δ13C of ethanol. These data are in line with those in the literature or reported in corresponding official methods, and sr and sR of balsamic vinegar are in line with those of vinegar and must. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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Article
Fatty Acid and Stable Carbon Isotope Composition of Slovenian Milk: Year, Season, and Regional Variability
Molecules 2020, 25(12), 2892; https://doi.org/10.3390/molecules25122892 - 23 Jun 2020
Cited by 3 | Viewed by 1006
Abstract
This study examined the percentage and stable isotope ratios of fatty acids in milk to study seasonal, year, and regional variability. A total of 231 raw cow milk samples were analyzed. Samples were taken twice per year in 2012, 2013, and 2014, in [...] Read more.
This study examined the percentage and stable isotope ratios of fatty acids in milk to study seasonal, year, and regional variability. A total of 231 raw cow milk samples were analyzed. Samples were taken twice per year in 2012, 2013, and 2014, in winter and summer, covering four distinct geographical regions in Slovenia: Mediterranean, Alpine, Dinaric, and Pannonian. A discriminant analysis model based on fatty acid composition was effective in discriminating milk according to the year/season of production (86.9%), while geographical origin discrimination was less successful (64.1%). The stable isotope composition of fatty acids also proved to be a better biomarker of metabolic transformation processes in ruminants than discriminating against the origin of milk. Further, it was observed that milk from Alpine and Mediterranean regions was healthier due to its higher percentage of ω-3 polyunsaturated fatty acid and conjugated linoleic acid. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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Article
Can We Discover Truffle’s True Identity?
Molecules 2020, 25(9), 2217; https://doi.org/10.3390/molecules25092217 - 08 May 2020
Cited by 10 | Viewed by 1715
Abstract
This study used elemental and stable isotope composition to characterize Slovenian truffles and used multi-variate statistical analysis to classify truffles according to species and geographical origin. Despite the fact that the Slovenian truffles shared some similar characteristics with the samples originating from other [...] Read more.
This study used elemental and stable isotope composition to characterize Slovenian truffles and used multi-variate statistical analysis to classify truffles according to species and geographical origin. Despite the fact that the Slovenian truffles shared some similar characteristics with the samples originating from other countries, differences in the element concentrations suggest that respective truffle species may respond selectively to nutrients from a certain soil type under environmental and soil conditions. Cross-validation resulted in a 77% correct classification rate for determining the geographical origin and a 74% correct classification rate to discriminate between species. The critical parameters for geographical origin discriminations were Sr, Ba, V, Pb, Ni, Cr, Ba/Ca and Sr/Ca ratios, while from stable isotopes δ18O and δ13C values are the most important. The key variables that distinguish T. magnatum from other species are the levels of V and Zn and δ15N values. Tuber aestivum can be separated based on the levels of Ni, Cr, Mn, Mg, As, and Cu. This preliminary study indicates the possibility to differentiate truffles according to their variety and geographical origin and suggests widening the scope to include stable strontium isotopes. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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Article
Use of Lead Isotopic Ratios as Geographical Tracer for Lambrusco PDO Wines
Molecules 2020, 25(7), 1641; https://doi.org/10.3390/molecules25071641 - 02 Apr 2020
Cited by 5 | Viewed by 960
Abstract
In this study, the lead isotope signature was tested with the aim to verify its potential as geographic tracer for wine production and particularly for the Lambrusco PDO wines of the province of Modena (Italy). A solid phase extraction procedure, for separating lead [...] Read more.
In this study, the lead isotope signature was tested with the aim to verify its potential as geographic tracer for wine production and particularly for the Lambrusco PDO wines of the province of Modena (Italy). A solid phase extraction procedure, for separating lead from the investigated matrices, soil and wine, was optimized. Furthermore, different mathematical models, based on an exponential law and internal or external correction approach, were evaluated for the correction of instrumental mass dependent fractionation. The optimized analytical procedure yielded isotopic ratio data relative to the lead NIST 981 standard, 208Pb/206Pb = 2.16664 and 207Pb/206Pb = 0.914645, in good agreement both with the tabulated values and with the most recent literature data. Measured isotope ratio data highlight the contribute of multiple lead sources in bottled wine but different from the one present in soils. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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Article
Acorn Isotopic Composition: A New Promising Tool for Authenticity Maps of Montado’s High-Value Food Products
Molecules 2020, 25(7), 1535; https://doi.org/10.3390/molecules25071535 - 27 Mar 2020
Cited by 4 | Viewed by 1408
Abstract
It is often overlooked that even food production is linked to the ecology of plants and animals. Living organisms respond to environmental short-and long-term variability: acknowledging this may help in the ultimate goal of valorizing a territory/product. We investigated acorns of the two [...] Read more.
It is often overlooked that even food production is linked to the ecology of plants and animals. Living organisms respond to environmental short-and long-term variability: acknowledging this may help in the ultimate goal of valorizing a territory/product. We investigated acorns of the two main Quercus species of the Portuguese Montado, a main feed of the renown black Iberian pig. We tested their responses to an aridity gradient by morphological parameters and isotopic signature. Q. rotundifolia and Q. suber acorns did not differ morphologically, even if a higher variability in all parameters was observed in acorns of Q. suber. According to the site-specific Aridity Index, correlations are indicative to higher weight and length only in Q. suber acorns from more arid sites. As for isotopic composition, there were no differences in nitrogen or carbon (δ15N and δ13C) between the two species. However, combining the samples and testing for association with the Aridity Index, we found that more arid sites lead to a 15N enrichment. This result, combined with the positive correlation between AI and acorns length, support the use of acorns as a tool, their isoscapes of nitrogen being a stepping stone for the provenance of the black Iberian pig. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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Article
Carbon and Nitrogen Isotope Ratios of Food and Beverage in Brazil
Molecules 2020, 25(6), 1457; https://doi.org/10.3390/molecules25061457 - 24 Mar 2020
Cited by 10 | Viewed by 2244
Abstract
Several previous studies on targeted food items using carbon and nitrogen stable isotope ratios in Brazil have revealed that many of the items investigated are adulterated; mislabeled or even fraud. Here, we present the first Brazilian isotopic baseline assessment that can be used [...] Read more.
Several previous studies on targeted food items using carbon and nitrogen stable isotope ratios in Brazil have revealed that many of the items investigated are adulterated; mislabeled or even fraud. Here, we present the first Brazilian isotopic baseline assessment that can be used not only in future forensic cases involving food authenticity, but also in human forensic anthropology studies. The δ13C and δ15N were determined in 1245 food items and 374 beverages; most of them made in Brazil. The average δ13C and δ15N of C3 plants were −26.7 ± 1.5‰, and 3.9 ± 3.9‰, respectively, while the average δ13C and δ15N of C4 plants were −11.5 ± 0.8‰ and 4.6 ± 2.6‰, respectively. The δ13C and δ15N of plant-based processed foods were −21.8 ± 4.8‰ and 3.9 ± 2.7‰, respectively. The average δ13C and δ15N of meat, including beef, poultry, pork and lamb were -16.6 ± 4.7‰, and 5.2 ± 2.6‰, respectively, while the δ13C and δ15N of animal-based processed foods were −17.9 ± 3.3‰ and 3.3 ± 3.5‰, respectively. The average δ13C of beverages, including beer and wine was −22.5 ± 3.1‰. We verified that C-C4 constitutes a large proportion of fresh meat, dairy products, as well as animal and plant-based processed foods. The reasons behind this high proportion will be addressed in this study. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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Review

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Review
Phenolic Compounds in Poorly Represented Mediterranean Plants in Istria: Health Impacts and Food Authentication
Molecules 2020, 25(16), 3645; https://doi.org/10.3390/molecules25163645 - 10 Aug 2020
Cited by 2 | Viewed by 1479
Abstract
Phenolic compounds are well-known bioactive compounds in plants that can have a protective role against cancers, cardiovascular diseases and many other diseases. To promote local food development, a comprehensive overview of the phenolic compounds’ composition and their impact on human health from typical [...] Read more.
Phenolic compounds are well-known bioactive compounds in plants that can have a protective role against cancers, cardiovascular diseases and many other diseases. To promote local food development, a comprehensive overview of the phenolic compounds’ composition and their impact on human health from typical Mediterranean plants such as Punica granatum L., Ziziphus jujuba Mill., Arbutus unedo L., Celtis australis L., Ficus carica L., Cynara cardunculus var. Scolymus L. is provided. Moreover, the potential use of these data for authenticity determination is discussed. Some of the plants’ phenolic compounds and their impact to human health are very well determined, while for others, the data are scarce. However, in all cases, more data should be available about the content, profile and health impacts due to a high variation of phenolic compounds depending on genetic and environmental factors. Quantifying variation in phenolic compounds in plants relative to genetic and environmental factors could be a useful tool in food authentication control. More comprehensive studies should be conducted to better understand the importance of phenolic compounds on human health and their variation in certain plants. Full article
(This article belongs to the Special Issue Isotopic Techniques for Food Science)
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