Nanomaterials can be technologically produced specifically for the food industry. The array of possible applications in foods as well as in food contact materials is vast, ranging from antimicrobial packaging, through encapsulating substances to protect them from oxidation, to improved bio-availability of substances.
Under the leadership of the Institute for Food Technology and Bioprocess Engineering, the Max Rubner Institute conducts cross-institute research on nanoparticles in foods. Currently, our focus is on developing verification and characterisation methods for technologically produced nanomaterials. Detecting and characterising them in a complex food matrix is vital for determining human exposure to technologically produced nanomaterials as well as for assessing the pathway and biological effects of these nanomaterials after oral ingestion.
However, MRI also conducts application research. Some food contact materials are already being marketed outside of the EU, such as packaging foils, cutting boards, or food containers. They contain nano-scale silver particles, called “nano-silver that are supposed to have antimicrobial effects. MRI has conducted two projects to study antimicrobial effects in such food contact materials as well as possible leaching of silver nano-particles into foods.
Another interesting research area is nano-capsules as carrier systems for (bio-)active substances that serve to emulsify water-insoluble substances in water or water-soluble substances in oil. Encapsulated active substances are better protected from oxidation during processing and storage and can better withstand the passage through the digestive tract and absorption by the human body. This principle occurs in nature: one example is micellar casein, which is a natural nanoparticle in milk that encases calcium and transports it into the body. MRI is investigating how nano-encapsulation or extremely fine grinding of plant material can increase the absorption of bioactive substances in the body (bio-availability). Other research projects focus mainly on the question as to whether and how the use of nano-encapsulated plant materials can extend the shelf life of fish products in oil-in-water emulsions.
The complex composition of foods causes interactions between nano-materials and food components such as proteins, carbohydrates, and fats. These interactions can change the characteristics of nanoparticles. MRI therefore studies models of interactions, such as oil-in-water emulsions and protein gels, in order to gain a fundamental understanding of these mechanisms.
The nanomaterials used as well as their interactions with the food matrix must be recorded metrologically. Since there is no standard method to characterise nanomaterials in complex systems such as foods, the analytical methods, like sample preparation and measuring, are constantly being developed, adapted and optimised.