Thomas Kuballa

Thomas Kuballa
Chemisches und Veterinäruntersuchungsamt Karlsruhe | CVUA · Water, Beverages, NMR

Professor

About

147
Publications
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3,196
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Publications

Publications (147)
Article
Full-text available
Highly reactive decomposition products of deuterated chloroform can deteriorate samples dissolved in this commonly used solvent for nuclear magnetic resonance (NMR) spectroscopy. Samples for metabolomics studies often contain a complex mixture of sensitive substances such as phospholipids, peptides, unsaturated fatty acids or vitamins. If these rea...
Article
The animal species of raw meat and processed meat products was determined by 1H NMR spectroscopy with subsequent multivariate data analysis. Sample preparation was based on comprehensive lipid extraction to capture nonpolar and polar (amphiphilic) fat components of meat. A nontargeted approach was used to analyze the 1H NMR data, followed by a prin...
Article
Full-text available
Craft breweries that tend to convince consumers with new interpretations of (ancient) beer styles increasingly influence the traditional beer market. Thereby, also ingredients not directly compliant with German beer purity laws come into use. Official food control currently faces the general problem of verifying food authenticity based on instrumen...
Article
Lebensmittelauthentizität ist eine komplexe Fragestellung mit vielfältigen Aspekten, wie z.B. dem geographischen Ursprung mit EU-Qualitätsregelungen. Produkte mit solchen Spezifikationen haben einzigartige Merkmale und sind häufig qualitativ hochwertig, weswegen sie oft gefälscht werden. Neben dem geographischen Ursprung gibt es weitere Möglichkeit...
Article
Full-text available
Coffee silver skin is produced in large amounts as a by-product during the coffee roasting process. In this study, coffee silver skin of the species Coffea arabica L. and Coffea canephora Pierre ex A. Froehner as well as silver skin pellets produced in the coffee industry were characterized with respect to both nutritional value and potential heat-...
Article
Full-text available
Toxicologically relevant levels of the psychoactive ∆9-tetrahydocannabinol (∆9-THC) as well as high levels of non-psychoactive cannabinoids potentially occur in CBD (cannabidiol) oils. For consumer protection in the fast-growing CBD oil market, facile and rapid quantitative methods to determine the cannabinoid content are crucial. However, the curr...
Preprint
Full-text available
Toxicologically relevant levels of the psychoactive ∆9-tetrahydocannabinol (∆9-THC) as well as high levels of non-psychoactive cannabinoids potentially occur in CBD (cannabidiol) oils. For consumer protection in the fast-growing CBD oil market, facile and rapid quantitative methods to determine the cannabinoid content are crucial. However, the curr...
Article
Full-text available
The food additive sorbic acid is considered as an effective preservative for certain cereal products, and propionic acid is commonly added in bakery wares, e.g., bread and fine bakery wares. The aim of this study was to develop and validate a new nuclear magnetic resonance spectroscopy (1H NMR) method for the routine screening and quantification of...
Preprint
Full-text available
The food additive sorbic acid is considered as an effective preservative for certain cereal products, and propionic acid is commonly added in bakery wares, e.g. bread and fine bakery wares. The aim of this study is to develop and validate a new nuclear magnetic resonance spectroscopy (¹H NMR) method for routine screening and quantification of...
Article
Full-text available
Due to legal regulations, the rise of globalised (online) commerce and the need for public health protection, the analysis of spirit drinks (alcoholic beverages >15% vol) is a task with growing importance for governmental and commercial laboratories. In this article a newly developed method using nuclear magnetic resonance (NMR) spectroscopy for th...
Preprint
Full-text available
Due to legal regulations, the rise of globalised (online) commerce and the need for public health protection, the analysis of spirits (alcoholic beverages > 15 % vol) is a task with growing importance for governmental and commercial laboratories. In this article a newly developed method using nuclear magnetic resonance (NMR) spectroscopy for the si...
Article
Background Coffee is a popular beverage with two species, Coffea canephora and C. arabica, being commercially exploited. The quality and commercial value of coffee is dependent on species and processing. C. arabica typically obtains a higher price on the market compared to C. canephora. Coffee beans undergo roasting during processing, resulting in...
Article
Full-text available
Monitoring coffee quality as a means of detecting and preventing economically motivated fraud is an important aspect of international commerce today. Therefore, there is a compelling need for rapid high throughput validated analytical techniques such as quantitative proton nuclear magnetic resonance (NMR) spectroscopy for screening and authenticity...
Preprint
Full-text available
Monitoring coffee quality as a means of detecting and preventing economically motivated fraud is an important aspect of international commerce today. Therefore, there is a compelling need for rapid high throughput validated analytical techniques such as quantitative proton NMR spectroscopy for screening and authenticity testing. For this reason, we...
Article
Full-text available
Furan fatty acids (FuFAs) are a class of naturally occurring minor fatty acids with fish as the richest food source. Typically, FuFA analysis is cumbersome and involves several steps. We developed a quantitative 1H NMR method (qNMR) in which fish oil samples were directly measured after dilution with CDCl3 stabilized with silver (which was essentia...
Article
Honig ist ein naturbelassenes Lebensmittel und das soll es auch bleiben. Blütennektar und/oder Honigtau wird von fleißigen Bienen gesammelt und zu Honig umgesetzt. Es gibt strenge lebensmittelrechtliche Vorgaben bezüglich der Gewinnung, Beschaffenheit und Kennzeichnung um die Qualität des Honigs für den Verbraucher zu garantieren. Das Produkt Honig...
Chapter
The World Health Organization estimates that globally out of the 6.2 L of pure alcohol consumed per person (15 + years), 25% is unrecorded alcohol. Unrecorded alcohol is defined as alcohol not registered in the legislation where it is consumed and includes homemade, surrogate, and counterfeit alcohols. Since the production, distribution, and consum...
Article
This article points out some important requirements for accurate analysis of MOSH (mineral oil saturated hydrocarbons) and MOAH (mineral oil aromatic hydrocarbons) using NMR spectroscopy. These include the selection of integration windows of MOSH not above delta 3.0 ppm as this might lead to inclusion of non-aliphatic compounds, but also the exclus...
Article
Full-text available
In cosmetic products, hydrocarbons from mineral oil origin are used as ingredients in a wide variety of consistency, from liquid oil to solid wax. Refined mineral oil hydrocarbons consist of MOSH (mineral oil saturated hydrocarbons) and a low proportion of MOAH (mineral oil aromatic hydrocarbons). MOSH and MOAH comprise a variety of chemically simi...
Article
Both the German and European organic food markets are growing fast, and there is also a rising demand for organic chicken eggs. Consumers are willing to pay higher prices for organic eggs produced in an animal appropriate environment considering animal welfare. Strict labelling requirements do not prevent chicken eggs from being a subject of food f...
Article
Full-text available
The four heat-induced coffee contaminants—acrylamide, furfuryl alcohol (FA), furan and 5-hydroxymethylfurfural (HMF)—were analyzed in a collective of commercial samples as well as in Coffea arabica seeds roasted under controlled conditions from very light Scandinavian style to very dark Neapolitan style profiles. Regarding acrylamide, average conte...
Article
Full-text available
Die 1H NMR-Spektroskopie, eine schnelle und effektive „Fingerprint-Methode“, bietet in Kombination mit chemometrischen Analysetechniken eine Möglichkeit der Haltungsüberprüfung von Hühnereiern.
Preprint
Full-text available
The three heat-induced coffee contaminants acrylamide, furfuryl alcohol (FA) and 5-hydroxymethylfurfural (HMF) were analyzed in a collective of commercial samples as well as in Coffea arabica seeds roasted under controlled conditions from very light Scandinavian style to very dark Neapolitan style profiles. Regarding acrylamide, average contents in...
Article
Beverage fraud involving counterfeiting of brand spirits is an increasing problem not only due to deception of the consumer but also because it poses health risks e.g. from possible methanol admixture. Suspicious spirit samples from Russia and Kenya were analysed using 1H nuclear magnetic resonance (NMR) spectroscopy in comparison to authentic prod...
Article
Full-text available
Mineral oils (such as paraffinum liquidum or white oil), which consist of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH), are widely applied in various consumer products such as medicines and cosmetics. Contamination of food with mineral oil may occur by migration of mineral oil containing products from packa...
Article
Nuclear magnetic resonance (NMR) spectroscopy has achieved increased application in the field of food authenticity control. Its instrumental variability is very low so that it is possible to compile large databases of authentic spectra. Adulterations in food fraud cases can be detected and quantification of compounds for regulatory limits control c...
Chapter
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In diesem Programm sollte erneut geprüft werden, ob die Hersteller seitdem wirksame Maßnahmen zur Reduzierung von Benzolgehalten in Karottengetränken für Säuglinge und Kleinkinder getroffen haben. Diese Ergebnisse sollten mit denen des BÜp aus dem Jahr 2011 verglichen werden. Zusätzlich sollte der Status von Kirschgetränken für Säuglinge und Kleink...
Article
Full-text available
A simple, rapid, and selective quantitative nuclear magnetic resonance spectroscopic method was evaluated for the determination of the content of fluorinated pharmaceuticals. 19F NMR spectra were either obtained in dimethylsulfoxide-d 6 or aqueous buffer, using trifluoroacetic acid as internal standard. Quantification of 13 fluorine-containing phar...
Article
Full-text available
Die Bezeichnung Schwarzwaldforelle ist seit dem 25.11.1997 in das Verzeichnis der geographisch geschützten Angaben (g. g. A.) der EU aufgenommen und darf seither nur noch nach den in den entsprechenden EU-Verordnungen (z. Z. VO (EU) 1151/2012) niedergelegten Regeln erzeugt und in Verkehr gebracht werden. Wenn die Bezeichnung "Schwarzwaldforelle" ve...
Article
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Für einen effizienten Verbraucherschutz hat das CVUA Karlsruhe ein ressourcenschonendes Screening-Verfahren auf Basis der quantitativen Nuclear-Magnetic -Resonance-Spektrometrie (qNMR) etabliert, welches in einem Analysengang elf verschiedene wertgebende Bestandteile von Erfrischungsgetränken bestimmen kann. Aufbauend auf dieser Methode wurde vom C...
Article
Full-text available
Mineral hydrocarbons consist of two fractions, mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). MOAH is a potential public health hazard because it may include carcinogenic polycyclic compounds. In the present study, 400 MHz nuclear magnetic resonance (NMR) spectroscopy was introduced, in the context of offici...
Preprint
Full-text available
Mineral hydrocarbons consist of two fractions, mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). MOAH is a potential public health hazard because it may include carcinogenic polycyclic compounds. In the present study, 400 MHz nuclear magnetic resonance (NMR) spectroscopy was introduced, in the context of offici...
Article
Samples of unrecorded opaque beers (n=58; 40 based on maize, 5 on sorghum and 13 on other plants) and recorded wines (n=8) in Kenya were screened for aflatoxins using a rapid ELISA technique followed by confirmation using liquid chromatography-tandem mass spectrometry. Six of the maize beers were obtained from Kibera slums in Nairobi County. Aflato...
Article
Full-text available
Nuclear magnetic resonance (NMR) spectroscopy is evaluated as an efficient analytical technique for simultaneous identification and quantitation of multiple compounds in alcohol-free beverages. The method was validated for three different types of soft drinks, including a beverage with high sugar content, a diet product and an energy drink. The sam...
Article
Full-text available
Aktuelle Untersuchungsergebnisse aus dem CVUA Karlsruhe zeigen, dass es derzeit keinen Grund zur Sorge um einen verbotenen Einsatz von Melamin in Proteinpulvern und Nahrungsergänzungsmitteln gibt. Mit einer neuen Untersuchungsmethode wurden verschiedene Proben auf Melamin untersucht. Dabei konnten keine Verunreinigungen oder Verfälschungen mit dies...
Article
Vor 500 Jahren, am 23. April 1516, wurde in Ingolstadt durch den bayerischen Herzog Wilhelm IV. und seinen Bruder Herzog Ludwig X. eine Landesverordnung erlassen, die einen Passus enthielt, der heute als „Reinheitsgebot des Bieres“ bekannt ist. Nach dieser Verordnung durfte zur Bierherstellung nur Gerste, Hopfen und Wasser verwendet werden. Hefe wu...
Data
Supplementary Figures S1-S13 (19F NMR spectra of all investigated compounds).
Article
Full-text available
Saffron, the dried stigmata of the plant Crocus sativus L., is a spice used for colouring and flavouring food. It is considered to be the most expensive spice, which can be explained by the laborious way the stigmata have to be harvested. There is a considerable profit to be made by adulterating saffron, e.g. by mixing it with other saffron plant m...
Article
Nuclear magnetic resonance (NMR) spectroscopy was applied to the analysis of alcoholic products in the context of health and safety control. A total of 86 samples of unrecorded alcohol were collected in Novosibirsk and nearby cities in Russia. Sampling was based on interviews with alcohol dependent patients, and unrecorded alcohol thus defined incl...
Article
Full-text available
Eiweißstoffe ( Proteine ) beeinflussen maßgeblich den gesamten Prozess des Bierbrauens sowie die Eigenschaften des erhaltenen Bieres. So sind sie nicht nur für den Geschmack und die Vollmundigkeit von Bier verantwortlich, sondern auch für die Bildung und Stabilität des Bierschaumes sowie für die Trübung eines Bieres. Der Eiweißgehalt von Bier wird...
Article
Full-text available
The consumption of alcoholic beverages has been classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC) since 1988. More recently, in 2010, ethanol as the major constituent of alcoholic beverages and its metabolite acetaldehyde were also classified as carcinogenic to humans. Alcoholic beverages as multi-compon...
Article
A nuclear magnetic resonance (NMR) method was developed to quantify cations in mineral water. The procedure was based on integration of signals from metal-ethylenediaminetetraacetic acid (EDTA) complexes at δ 2.70 ppm for Mg²⁺ and δ 2.56 ppm for Ca²⁺. The limits of detection were below 0.5 mg/L. Lack of precision did not exceed 5%. Linearity was be...
Conference Paper
Full-text available
The globalization of trade of foods with its overwhelming variety has led to an increased demand for authentic products by all parts of the food value chain. In particular high-priced products are commonly adulterated, mislabeled or completely substituted. Honey is a typical example for such foods, which show an increasing number of adulterations,...
Poster
Full-text available
UV-C treatment of grape must or wine is a promising approach to control the growth and activity of microorganisms during the winemaking process. This method is independent from the addition of sulfur dioxide, however, it may affect the chemical composition of the must or wine. Especially constituents Iike polyphenols are able to absorb UV-C light,...
Article
Full-text available
Biermischgetränke erfreuen sich nach wie vor großer Beliebtheit und der jährliche Absatz von Biermischungen liegt bei etwa 4 Millionen Hektolitern [1]. Üblicherweise handelt es sich hierbei um Mischungen aus Bier und Limonade oder Mineralwasser oder anderen Zusätzen wie z. B. Cola. Je nach Region tragen Biermischgetränke häufi g unterschiedliche Be...
Article
Full-text available
Biermischgetränke erfreuen sich nach wie vor großer Beliebtheit und der jährliche Absatz von Biermischungen liegt bei etwa 4 Millionen Hektolitern [1]. Üblicherweise handelt es sich hierbei um Mischungen aus Bier und Limonade oder Mineralwasser oder anderen Zusätzen wie z. B. Cola. Je nach Region tragen Biermischgetränke häufig unterschiedliche Bez...
Technical Report
Full-text available
In the first part of the NMR technical report (see Guide to NMR Method Development and Validation – Part I: Identification and Quantification), the special criteria to facilitate development of NMR-based applications is described. These guidelines (Part I) mostly deal with general requirements, such as NMR spectra acquisition, identification, devel...
Article
Full-text available
The role of the peregrine falcon (Falco peregrinus) as a bioindicator for the accumulation of organohalogen compounds and other persistent organic pollutants has been established in field studies. Biometric indices for damage caused by pollutants such as the shell thickness and the shell index were determined and the egg contents were analyzed for...
Article
Full-text available
Recent studies have detected microplastic fibres and particles in some food groups including honey and beer. The aim of this work was to replicate a method for micro plastic analysis in beer. Several methodological pitfalls were detected in the literature method, including the staining agent rose bengal used in microscopic analysis, which false-neg...
Article
A fast and reliable nuclear magnetic resonance (NMR) method for quantitative analysis of targeted compounds with overlapped signals in complex mixtures has been established. The method is based on the combination of chemometric treatment for spectra deconvolution and the PULCON principle (pulse length based concentration determination) for quantifi...
Article
Full-text available
Ob Flasche oder Dose, jeder kennt sie, jeder mag sie – oder auch nicht. Energydrinks gehören mit zu den Lebens­mitteln, über die seit Jahren am meisten diskutiert wird. Wie haben Sie es geschafft, sich in der großen Getränkewelt zu etablieren und zu behaupten? Was steckt eigentlich in der Dose, die für viele so anziehend erscheint?
Article
Full-text available
Electronic cigarettes (e-cigarettes) are advertised to tobacco users as a tool to decrease cigarette consumption and to reduce toxic exposure associated with conventional tobacco smoking. Little is known about the compounds contained in such products, their exposure and long-term health effects. NMR spectroscopy was used to ascertain the content of...
Article
An eight-fold suppression pulse sequence was recently developed to improve sensitivity in 1H NMR measurements of alcoholic beverages [Magn. Res. Chem. 2011 (49): 734–739]. To ensure that only one combined hydroxyl peak from water and ethanol appears in the spectrum, adjustment to a certain range of ethanol concentrations was required.To explain thi...
Article
This paper reports 1H NMR and NIR spectroscopic analysis of hydrogen bonding in acetone mixtures with water, CHCl3, CCl4, and CDCl3 with varying acetone concentrations (0–100 vol%). Spectroscopic data were chemometrically analyzed using independent component analysis to resolve the spectra of complexes existing in the solutions and to obtain their...
Article
1,3-Dimethylamylamine (DMAA) is a stimulant that can be found in pre-workout sports nutrition and dietary supplements. This practice is illegal because DMAA is not a safe food ingredient but rather an unapproved medicinal compound due to its pharmacological action. In order to determine the DMAA content in such products, a nuclear magnetic resonanc...