NMR

Speciation of Meat

Application Note 6BackgroundIn recent years there have been a number of scandals involving fraudulent mislabelling ofmeat in the human food sales chain, in order for the perpetrators to gain criminal monetaryadvantage. One prominent example in 2013 was the horsemeat scandal in Europe, where
food products labelled as “beef” were found to contain significant amounts of horsemeat.
While not hazardous to health, this activity nevertheless constitutes criminal fraud, as theconsumer is paying for a premium product (beef) but receiving a cheaper one (horse).
To combat this activity it is important that reputable food producers and regulators
have methods at their disposal to quickly and reliably check that a meat product iswhat it is claimed to be.
The traditional method of analysis

X-Pulse

The traditional method for identification of meat species is

X-Pulse is a high performance benchtop Nuclear Magnetic

Polymerase Chain Reaction (PCR) and/or gene sequencing

Resonance (NMR) spectrometer operating at 60MHz proton

which, although highly specific, takes several hours tofrequency. It uses a permanent magnet, so does not requirecomplete. Enzyme-linked immunosorbent assay (ELISA) tests

liquid nitrogen, liquid helium, or compressed gasses, andare also used and although they are cheaper and quicker thanit has no special health and safety requirements. It can be

the PCR tests, they are still more expensive per test than theoperated in a normal analytical laboratory by non-NMR expert

X-Pulse method.

laboratory technicians.

The X-Pulse method
The X-Pulse method has been developedin collaboration Quadram Institute
Bioscience (formerly the Institute of FoodResearch) in Norwich, UK. The method
works by analysing the high resolution
60MHz NMR spectrum of oil or fat
extracted from a meat sample to determine
the fatty acid composition of the meat (seeX-Pulse application note 5). Different meat
species exhibit different fatty acid profiles,
and these profiles can be used to identify
the meat species being tested (see Figure1). In practice, there is a certain amount of
natural variation between samples of thesame meat species, due (for example) toorigin, method of feeding, the cut of themeat, etc., so a chemometrics approachhas been developed to classify the fatty
acid profiles and provide automateddifferentiation.

Figure 1 Fatty acid profiles of common meat species

Speciation of Meat

NMR
Application Note 6

Measurement process
Solid meat samples are firsthomogenised, then a representative
sub-sample of 3 - 4g is shaken in a vialwith 1.5ml chloroform. The mixture isthen filtered, and pipetted into a 5mm
NMR tube. The tube is then inserted
into the X-Pulse instrument and aspectrum is collected. The spectrum istransferred to the special applications
software for analysis.
Measurement time
The total measurement time, including sample
preparation, is typically less than 5 minutes for mostsamples, but could be up to an hour for very lean samples.

Results
The special ConfirMeat software
displays the predicted meat speciesof the sample, and indicates where
the measurement result lies in thechemometric model. See Figure 2 foran example of the results output.

Figure 2 Output of ConfirMeat method

Applicability and limitations
The ConfirMeat method is intended for the testing of unblended meat samples, to verify whether or not the sample is of thespecies it is claimed to be. The method cannot be used to quantify constituents in mixtures of meat species, or to detect tracecontamination of one meat species with another. Currently a database is available containing samples of beef, pork and horse.
Identification of other meat species is perfectly possible, but requires the user to build up a suitable database of samples forcomparison.

Summary
X-Pulse provides a fast, convenient and reliable method for identifying meat species. X-Pulse does not require liquid helium,
liquid nitrogen, or compressed gases, and can be operated in a normal laboratory environment without any special health andsafety considerations.

Also available:
X-Pulse for fatty acid compositionof Triglycerides
X-Pulse also provides a fast andsimple method for analysis of fatty
acid composition in oils and fats. The
method works for liquid oils and for oils
extracted from solid foodstuffs,
and takes typically less than
5 minutes per sample.

MQC+ benchtop NMR analysers for fastand easy measurement of total oil or fat.
Applications include:• Fat in food• Solid Fat Content (SFC)• Oil in snack food
• Fat in chocolate• Oil & moisture in seeds

visit nmr.oxinst.com/x–pulse for more information or email magres@oxinst.com

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