Application of NMR in the food industry

NMR is one of the new techniques used in the food industry. This technique was generally discovered in 1946 and its first application in the food industry related to the detection of compounds in food was reported in 1970. NMR is able at the molecular level of physical and chemical properties of various systems To analyze. The basis of NMR work is the analysis of the nuclei of atoms that are inherently magnetic and can act like very small magnets. Fruit ripening, etc. can be examined by NMR. Also, NMR under favourable conditions can have a germicidal effect and is used in various processes.

Simplified NMR is the term Nuclear Magnetic Resonance. It was first discovered independently in 6491 by Felix Bloch of Stanford University and Edward Parcel of Harvard University. They were able to show the absorption of electromagnetic radiation as a result of the transfer of the energy level of the nucleus in a strong magnetic field. Particles like H + that have magnetic properties act like small magnets. These particles when placed in a magnetic field. They are in the direction of the field, also these particles change direction under the influence of radio waves, by cutting off the radio current source, these waves start moving to their original place. The speed of motion depends on the bond of this particle to other elements instead of the original. If this article has a strong bond with other elements, the rate of return to the initial state will be fast, and if it does not have a strong bond with other elements, the rate of return to the original state will be slow. In fact, in this system, the physicochemical properties of the material can be understood from the rate of return of the particle to its original state.

Because elements H and C make up the bulk of nutrients. In the food industry, H NMR and C NMR are mostly used, in H NMR, the analysis is based on how H returns to its original position. If  H   is tightly bound to the food, it returns to its original position more quickly after the radio wave source is cut off. But if it has a weaker connection with other elements, it will return to its original place at a slower rate. When the source of radio waves is cut off, the signal in the vertical axis decreases overtime to reach zero, which is why these diagrams (Free Induction Decay) are called FID.

The destructive effect of NMR on microorganisms

This property of NMR was discovered by Hoffman in 1946. Hoffman realized that if food were placed in the centre of the magnet, its microorganisms would be destroyed. For this application, NMR uses an oscillating field (sine field strength). Using a device that generates a 1 to 611 Tesla magnetic field. In this case, the frequency of 111-11 kHz is used with a pulse of about 1 logarithmic cycle reduces the population of microorganisms. Because we have a small temperature change in this system (about 1-1 ° C), the mechanism of destruction of microorganisms is not thermal. The mechanism of this action is still unclear. But two main mechanisms have been proposed for the destructive effect of NMR on microorganisms, which are:

1. The energy introduced by magnetic waves enters the components that have magnetic properties, ie atoms that have magnetic properties and can resonate (such as DNA, proteins, microorganisms, etc.), for example, change a peptide bond, and that The other part can not and does its main duty.

2- It may affect the mobility of ions in cells, and change the entry and exit of different ions.

Some enzymes need ions to work (cofactor). If the binding of these ions to the enzyme changes, the activity of the enzyme decreases and is lost.

'Application of NMR in the food industry' 'Application of NMR " " NMR" "NMR Solvents"

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Nuclear magnetic resonance applications: 

In Chines: 核磁共振应用

In Russian: Приложения ядерного магнитного резонанса

IN Germany: Kernspinresonanzanwendungen