Nuclear Magnetic Resonance (NMR) - Articles and news items
Issue 6 2015 • 9 December 2015 • Stephan Schwarzinger, Felix Brauer and Paul Rösch, Research Center for Bio-Macromolecules, University Bayreuth, ALNuMed GmbH / Bernd Kämpf, FoodQS GmbH, Markt Erlbach
Honey – for thousands of years it has been the only source of sweet taste, and it still is the prototype of an all-natural, healthy food. In particular with the growing trends for organic food and a healthy life-style honey has enjoyed steadily increasing popularity. Unfortunately, while demand is on the rise, supply is short. The reasons for this are complex and interwoven and have their origin in bee diseases, climate change as well as agro-industrial production methods. As a consequence, an increasing number of honeys mixed with non-natural sweet syrups has been detected in the international trade. Such economically motivated adulteration is seen also in other foods such as fruit juice, olive oil or wine, and it is most reliably exposed by NMR-profiling. This technology is based on the comparison of hundreds of spectral features of authentic honeys with the sample to be tested…
Featured news • 18 March 2015 • Bruker
Update of NMR FoodScreener™ module for wine now delivers easy and cost efficient analysis for quality and authenticity of samples regarding origin, variety and addition of water…
Issue 2 2013 • 26 April 2013 • Francesco Capozzi, Foodomics Laboratory, Department of Agro-Food Science and Technology, University of Bologna
Nuclear magnetic resonance (NMR) spectroscopy is an investigation technique to study matter. It is based on the properties of magnetically active nuclei, which respond to a perturbation induced in a sample by applying a radio wave pulse. The nuclei, if immersed in an intense magnetic field, respond to the pulse by oscillating at a particular frequency, thus generating a signal which is recorded and transformed by the instrument as a graph, the so-called spectrum, reporting the intensity of the response as a function of the oscillation frequency. The frequency of each nucleus is characteristic of its position in the molecule and depends on the physico-chemical state of the substances. The response depends, in fact, not only on the structure of the molecule to which the atom belongs to, but also on the chemical environment in which the molecule is immersed.
Issue 4 2012 • 6 September 2012 • Luisa Mannina, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma & Laboratorio di Risonanza Magnetica Annalaura Segre, Istituto di Metodologie Chimiche, CNR and Anatoly P. Sobolev Laboratorio di Risonanza Magnetica Annalaura Segre, Istituto di Metodologie Chimiche, CNR
NMR spectroscopy is currently one of the key methods for food characterisation1. Foodstuff is a complex matrix including many different compounds with different chemical structures, concentrations, solubility, properties and nutritional values. Each food type contains primary and secondary metabolites. Primary metabolites, i.e. organic acids, amino acids and sugars, involved in the basic functions of the living cell are ubiquitous although they are present in different species at different concentrations. Secondary metabolites such as phenolic compounds, terpenes and sterols are specific to food type and can be considered markers of the product. Together with primary metabolites, they are important from a nutritional point of view. NMR methodology enables primary and secondary metabolites to be identified and quantified, bringing high-throughput spectroscopic / structural information on a wide range of metabolites simultaneously with high precision.
NMR methodology is especially helpful for molecular identification. The metabolite identification is usually obtained by means of 1D and 2D experiments, addition of standard compounds, literature data and by comparison with a database of standard compounds. Moreover, the identification of metabolites in a mixture is often obtained without separation of individual components. Rather simple, direct and rapid sample preparation procedures without prerequisite derivatisation of components are usually required. 1H NMR is a quantitative technique owing to the proportionality of signal integral to the molar concentration of the corresponding metabolite.
Issue 3 2012 • 4 July 2012 • Serge Rezzi, Bioanalytical Science Department, Nestlé Research Centre
Since the pioneer discovery of nuclear magnetic resonance (NMR) spectroscopy by Isidor Rabi in 1938, it has become a central analytical technology in multiple scientific domains of chemistry, physics and biology. Uniquely suited to measure the spin properties of magnetically active nuclei, NMR has emerged as a very popular technique for both routine and research applications. The food industry for instance uses NMR to study food structure, composition and effects on the metabolism. We briefly review in the following some key features making NMR a successful analytical platform in modern food and nutrition industry. Emphasis is given to recent developments of high resolution NMR (HR-NMR) spectroscopy for food quality and authenticity and nutritional metabonomics.
The popularity of HR-NMR in food and nutrition research relies first with a series of technical advantages such as minimal sample prepara – tion, non-invasiveness, reduced matrix effects, detailed structural information, quantitative capacity within a broad dynamic range and high reproducibility. HR-NMR remains a technique of choice for establishing the structure of molecules as well as for analysing complex food matrices. Indeed, minimal structural modifications introduced by various stereo – chemistry, chiral centre and position of functional groups result in measurable changes of chemical shifts, signal multiplicity and couplings that can be exploited.
For many years, NMR spectroscopy was largely overlooked by the food industry. Maybe this was understandable. The instruments were expensive, the skills required to operate them could at best be described as specialist and there wasn’t a broad understanding of the way in which the technology could be applied within the industry. I joined the Food Science Group at Fera (then the Central Science Laboratory) in 1999. NMR spectroscopy was mainly used for measuring isotopes to check the authenticity of wines and fruit juice, whilst an archaic bench top contraption was used for fat and water measurements.
Issue 2 2009 • 1 June 2009 • Matthieu Adam-Berret and François Mariette, Cemagref & Université européenne de Bretagne
Fats are present in most food products and they have a significant importance for fat-containing products such as chocolate and butter. The physical properties of fats depend on the polymorphic behaviour and inter-solubility of their major triacylglycerol components and the phase behaviour of these mixtures is of paramount importance for the food industry. Indeed, fat structures formed by their crystals determine the functional properties of fat-containing products such as their texture, plasticity and morphology. DSC and XRD are the two techniques generally used to characterise fats. Crystal size is another important parameter for determining the physical properties of fats because it affects the rheological properties and consequently modifies taste, graininess and texture.
Water is a major constituent in many foods. For example, in several of our basic food items such as muscle-based foods and vegetables, water is the dominating component and is in many ways of primary importance for the quality of these products. Low-field proton NMR relaxometry is an excellent technique for studying water properties in […]
Issue 2 2008, Past issues • 13 June 2008 • J. P. M. van Duynhoven, Gert-Jan W. Goudappel, Elena Trezza, Adrian M. Haiduc, Franck Duval, Wladyslaw P. Weglarz, Unilever Food and Health Research Institute, Vlaardingen, The Netherlands
NMR is a versatile tool for structural assessment of food materials and this pertains in particular for its benchtop and hand-held implementations. Such “small NMR” equipment can literally be deployed in all phases of foods innovation. This is illustrated by several industry examples.
Important tasks of the fruit juice industry are to protect the good and healthy image for its whole product range and protect the market against any unserious producers. In order to assure fair competition, safe products and consumer satisfaction, the fruit juice industry has installed independent and centralised control bodies under the umbrella of EQCS (European Quality Control System). SGF (SGF INTERNATIONAL E.V. – SURE GLOBAL FAIR) is the biggest member association of and its department, SGF/IRMA (International Raw Material Assurance) and is in charge of controlling the supply market in more than 50 countries worldwide. Facing a very large number of control samples, conventional analyses are limited to spot checks and more or less arbitrary choices of specific aspects to control, due to high costs. Systematic so called “full analyses” are too expensive for any control organisation and for the companies’ own entrance controls. Besides safety controls, the analytical scope should cover the addition of external sugar, water, flavour compounds or cheaper fruit types than the declared ones1,2.
ABF Ingredients ANDEROL EUROPE BV Armfield Ltd Avantes Berndorf Band GmbH BIOTECON Diagnostics GmbH Cargo Oil AB Elea GmbH Engilico FUCHS LUBRITECH GmbH GLOBALG.A.P. Foodplus GmbH InS Services (UK) Ltd IONICON Analytik GmbH JAX INC. JBT Corporation LUBRIPLATE Lubricants Company NETZSCH Pumpen & Systeme GmbH NSF International Ocean Optics PCE Instruments UK Ltd R-Biopharm Rhone Ltd Randox Food Diagnostics Stancold SteriBeam The Tintometer® Group TOMRA Sorting Food Uhde High Pressure Technologies GmbH Verder UK Ltd Verner Wheelock Vikan UK Ltd