Food & Beverage

Although not yet used as commonly as in other scientific fields, Raman spectroscopy is gaining popularity as an analysis technique in food and beverage applications.

Typically, analytical techniques for food and beverage characterization involve determination of the composition via quantitative methods, quality control (including adulteration, bacterial contamination), and identification of impurities or undesired material. Usually, chromatography (GC, GC-MS, HPLC), is employed for such characterization but might be time-consuming, use solvents and require sample preparation. Additionally, contrary to infrared techniques, Raman spectroscopy is not sensitive to high water content, and is thus well adapted to analyze aqueous solutions.

Raman imaging of a thin section of maize cells on a CaF2 substrate.

Raman imaging of a thin section of maize cells on a CaF2 substrate
Acknowledgement : Dr Reg Wilson and Dr Klaus Wellner - Institute of Food Research (IFR), Norwich, United Kingdom

From macro to micro analysis
Raman spectroscopy can be used to examine powders, solids, liquids in different geometries. For example, bulk measurements for assessing the quality of powders or translucent samples can be performed by Transmission Raman to obtain spectra from large volumes. Quantitative analyses based on Raman spectroscopic data of bulk material, representative of the whole sample are then possible. On the other hand, micro Raman brings information on micrometer level, which is required when assessing the distribution of components in grains, particles within powders, or micro-organisms present in foods.

SERS analysis
Usually not sensitive to trace amounts of compounds and limited to the quantification and detection of the major compounds of a mixture, Raman spectroscopy, via the use of SERS (surface enhancement Raman spectroscopy), has proven to be very useful in the detection of trace materials such as pesticides in fruits. SERS involves the enhancement of the Raman signal, using gold or silver nano-substrates, thus allowing the detection of trace organic compounds down to ppm levels.

Typical applications:

  • Determination of fat / oil composition
  • Adulteration of oil
  • Detection and Identification of bacteria and other micro-organisms
  • SERS detection of pesticides in foods
  • Analysis of Carotenoïdes
  • Detection of Melamine in milk
  • Structural characterization of grains, crops, ...
  • Quantitative analysis

Application Notes

Food & Beverage - Application Notes

  • RA51 : Raman Characterisation of Fat Composition

    • Nils Kristian Afseth, Research Scientist, Nofima – Norwegian Institute of Food, Fisheries and Aquaculture Research, PB 210, N1431 - Aas, Norway
    • Vincent Larat, HORIBA Scientific, 231 rue de Lille, 59650 Villeneuve d’Ascq, France
    • Raman Spectroscopy was used as a probe for the analysis of fatty acids. The presented examples show that this technique can be used for characterisation of fats of both animal and vegetal origins.Two experimental configurations were used: backscattering and transmission, involving different analysis methods: point measurement, XY mapping and multivariate analysis.

  • RA52 : Characterisation of Encapsulated Flavours using Raman Spectroscopy

    • Zoran Mandžuka1, Marjan Donko1, Vincent Larat2
    • 1FrutaromEtol d.o.o., QualityAssuranceDepartment, Škofja vas 39, 3211 Škofja vas, 2HORIBA Scientific, 231 rue de Lille,
    • 59650 Villeneuve d’Ascq
    • Raman spectroscopy has been used to analyse the process of micro-encapsulation of flavours. This contribution shows the example of distribution of limonene and quantification of its content within the micro-particles.

  • RA55 : Transmission Raman Spectroscopy: review of applications.

    • Vincent Larat, HORIBA Scientific, 213 rue de Lille, 59650 Villeneuve d’Ascq, France
    • Variation of composition in fatty acids was established between the different fat layers (outer and inner) of adipose tissues. In that respect, being able to get an averaged spectrum of a bulk sample is necessary, if global information is required.
    • Transmission Raman spectroscopy provides such averaged information. Adipose tissues of lamb, veal and pork chops were measured: samples of various sizes and thicknesses were analyzed without any preparation by transmission Raman spectroscopy.

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