TwinTree Insert

19-03 Applications in Biology

spaceholder redFood

Water content and fat-water ratio are two important parameters in many ma­nu­fac­tu­­red food­stuffs. Control of product quality may depend critically on them, but the tra­­di­ti­o­nal chemical methods of measurements may take between a few hours to a day to complete.

NMR methods exist to perform such measurements in less than a minute which is fast enough to help in the control of the production line.

Some companies al­ready use spectrometers dedicated to this sort of work, but there is still room for a huge expansion in the market. Routine analysis is a to­tal­ly tri­vi­al task, however, it may take many weeks for a research scien­tist and a line ma­na­ger to develop an appro­priate method for each particular analytical task, and the num­ber of suitably trained sci­entists is very small.

spaceholder smallredAnother area of routine analysis is that of fruit juices, beer, and wine. The Europ­ean Community has sponsored the develop­ment of an NMR test for the qua­li­ty of wine, par­ti­cu­lar­ly to detect glycol adulter­ation. A routine method for de­ter­min­ing the al­co­hol content in fermentation vats in two-three minutes is avai­lable. Mag­ne­tic re­so­­nan­ce al­lows screening of beer, juices, and wine to au­then­ti­ca­te the origin, purity, and blending with other substances and liquids (SNIF NMR spec­tro­sco­py).

NMR is also useful as a research tool in food science, and MR imaging is be­gin­ning to be applied to foodstuffs as well. An early example was showing how heating to 40°C and then cooling produced a permanent change in the chocolate.

More recently the effect of freeze-thaw cycles on the structure of soft fruit and ve­ge­tab­les has been followed, and a particular promising use is the monitoring and vi­su­a­li­za­tion of the fat content of farmed fish (e.g., aquacul­ture of salmon).

Chlorine-35 (³⁵Cl) NMR was used to show how salt (sodium chloride) in­­ter­­ac­t­ed syn­er­gis­ti­cal­ly with the food additive sodium tripolyphosphate (E 400) so that a smal­ler amount of it still produced the de­sired effect, and ³¹P NMR has been used to demonstrate the hydrolysis of this additive when it is added to meat.

spaceholder smallredDetailed studies have been made of starch and carrageenans, a poly­­sac­­cha­­ri­­de ob­tain­ed from seaweed and used in large quantities in food manuf­acturing.

Starch and carrageenans are important in creating the correct texture in many foods and a fuller understanding of their proper­ties will help in production of chea­­per food of a higher quality and in the more efficient use of raw materials.

spaceholder redAgriculture, Forestry, and Envi­ronment

NMR techniques have only recently begun to be applied to plant systems but one ma­jor area already established is the phospho­rus and nitrogen nutrition of plants.

Basic research in this area can hopefully lead to a more efficient use of fertilizers and thereby lead to reduced pollution of rivers, lakes, and the seas.

MR imaging of plant systems is even younger than spectroscopy but in one study of frost damage in pot grown pine and spruce seedlings it was possible to detect da­mag­ed and dead root systems weeks be­fore the shoots showed any sign of damage.

For instance, with Sweden alone producing 600 million seedlings per year at a price of less than one Euro each, there is consider­able financial in­cen­ti­ve to pre­vent frost-damaged seedlings being planted out. As a basic research tool MR imaging of intact root systems could be invaluable in increas­ing the un­der­stand­ing of how root systems develop, and so help in tackling problems like optimizing the uptake of nu­tri­ents (es­­sen­tial in nutrient-poor soil) or in preventi­ng the blowing over of forest trees (wind throw) which is a source of major eco­nomic losses.

spaceholder smallredSolid-state ¹³C NMR studies of soil have helped soil scientists to understand the ra­ther large and complex organic molecules present in soil. For example, the che­mi­cal ana­ly­ti­cal methods used before the advent of solid-state NMR had se­ri­ous­ly un­der­es­ti­­ma­ted the per­cen­tage of aliphatic carbon groups as against aro­ma­tic carbon groups. An understanding of soil chemistry is im­portant when stu­dy­ing the nutrition of plants and when considering the environ­mental effects of, e.g., acid rain or ra­dio­ac­­tive fall-out after nuclear power plant accidents.

spaceholder smallredA full understanding of the conse­quences caused by increasing levels of green­house gases (especially carbon diox­ide and methane) must include the whole of the car­bon cycle. The soil is an important element of this cycle, having im­men­se amounts of carbon temporarily stabilized in the form of humus.

Direct monitoring of pollution is also possible, particularly in adverse environ­ments, e.g., the artic seas. The size of mus­sel populations, counted by divers, are cur­rently used as an indication of pollution. Recent laboratory results have re­veal­ed quite dis­tinc­ti­ve changes on the ³¹P spectra of mussels when subjected to low doses of pe­tro­che­mi­cals (benzene, phenol, formalin) or heavy metals (cad­mi­um, zinc, lead, mer­­cu­ry). It is hoped that a pollution monitor­ing system might be developed from this work.

19-04 Proteins and Protein Engineering

The latest advances in biochemistry have made it possible to begin to build pro­teins from scratch, and so in principle create a molecule to do a specific task. Be­cause it is the structure of the protein which controls its function, very precise in­for­ma­tion about the structure is essential and high-resolution NMR is one of the few ways of un­co­ver­ing it.

Magnetic resonance can help determine the structures of large biomolecules in pro­­te­o­no­mics, and add information in metabolomics research.

The NMR spectra reveal information about the neighboring atoms for each atom in the molecule. With even a small protein containing hundreds of atoms, one of the ma­jor problems is too much information. The spectroscopist can de­sign the NMR ex­­pe­ri­ment to keep the amount of information to a manageable level, and then mo­le­cu­lar modeling computer programs are used to generate three-dimensional struc­tures from the NMR data. Such research programs have for instance been applied in the devel­opment of new antibiotics as well as x-ray and magnetic resonance con­trast agents.

19-05 Non-Destructive Testing

Some applications of NMR in non-destruc­tive testing have been described be­fore, e.g., the examination of plastic and ceramic components.

Here, a broad ran­ge of appli­cations has been developed, but the spec­trum of pos­sible new ap­pli­ca­tions is wide. MR imaging, particularly diffusion studies, are used for non­­de­­struc­­ti­ve test­ing of, e.g., ceramics. Quality assurance by non-de­structive test­ing is applied for chemical, in­cluding pharmaceutical, dietary, and other raw ma­te­ri­als.

Space technology will exploit the possi­bilities of NMR to assess the influence of mi­cro­gra­vi­ty, ac­ce­le­ra­tion, and vibration upon materials and their possible de­gra­da­ti­on. Monitoring could be performed before and after space flights, and with suit­able equip­ment even in space.

Quality assurance programs with NMR include also measurement and control of other techniques such as chromatography. Small, robust NMR machines are already avail­able, and machines for particular ap­plications custom-tailored for specific tech­­ni­cal solutions can be developed at competi­tive prices, and sample chan­gers with high through­put for uninterrupted operation are available.