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Development of measurement procedures for the detection of particle size distributions in complex matrices using light scattering methods and field-flow fractionation
Project
Project code: MRI-LBV-08-LBV
Contract period: 01.01.2001
- 31.12.2019
Purpose of research: Applied research
Particle size has a significant impact on the processing characteristics and sensory and nutritional properties of foods. The determination of particle sizes in pure powders, dispersions or emulsions can easily be carried out whereas particle size analysis in complex matrices (food, culture media for cell culture, microbiology, etc.) is only possible after adequate sample preparation procedures. It should be noted that due to sample preparation, the particle size of the material of interest may not be changed.
Engineered nanoparticles and/or nanomaterials (ENs) could be present in food as ingredients or additives, but also as contaminants from the environment or from food contact materials. Several methods have been developed to detect ENs in simple matrices. However, a number of challenges will arise when analysing food and beverages for ENs. In contrast to simple matrices, food has a complex composition, is hetero-dispersed and may contain more than one type of EN. When analysing EN in foods, it is therefore not only their particle-size distribution of interest, but also the chemical composition as well as the physical and chemical properties of the ENs within the sample. No single technique can provide all relevant information. Therefore, a range of analytical techniques is required for detection and characterization of nanomaterials in foods. However, many analytical techniques are destructive and therefore a certain sample cannot be analyzed twice or by more than one technique. Furthermore, sample preparation methods very often lead to artefacts or changes of the ENs. The nature of ENs can also change over time; for example, particles could interact to form agglomerates or particles could dissolve. Additional problems arise because it is almost impossible to distinguish between natural and engineered nanomaterials and reference material is often lacking. In addition, the analytical techniques should be sensitive enough to measure low concentrations, as ENs in a food represent only a small part of the total mass. Furthermore different analytical methods such as SEM, SLS, DLS, BET or hydrodynamic chromatography lead in general to different size distributions resp. average particle sizes. Today, only a few analytical methods such as electron microscopy or atomic force microscopy are applicable to the analysis of particularly inorganic ENs such as TiO2 or SiO2 in food. Further suitable methods and procedures have to be developed.
Gräf V., Behsnilian D., Hetzer B., Walz E., Greiner R. (2012) Kleine Teilchen, große Herausforderungen – Nanomaterialien im Lebensmittelbereich. GIT Labor-Fachzeitschrift 8/2012, 581-583. Greiner R., Graef V., Walz E., Behsnilian D. (2011) Challenges in the Identification of Engineered Nanomaterials in Foods. Proceedings of the 11th International Congress on Engineering and Food (CD) NFP230. Greiner R., Graef V., Walz E., Behsnilian D. (2011) Detection and Characterization of Engineered Nanomaterials in Complex Matrices: Where are we today? Proceedings of the 9th Simpósio Latino Americano de Ciências de Alimentos, Campinas, Brazil, 35. Greiner R., Graef V., Walz E., Behsnilian D. (2011) Challenges in the Identification of Engineered Nanomaterials in Foods. Proceedings of the 11th International Congress on Engineering and Food, Vol. 1, 21-22. Greiner R., Graef V., Walz E., Behsnilian D. (2011) Challenges in the Identification of Engineered Nanomaterials in Foods. Proceedings of the German Nutrition Society, 34.
Section overview
Subjects
- Food Chemistry
- Food Processing
- Food microbiology
Framework programme
Funding programme
Excutive institution
MRI - Department of Food and Bio Process Engineering (MRI-LBV)
