Research Focuses
Research Focuses
- Motivation and Strategies
- Natural Nanostructurs in Foods
- Process Induced (secondary) Food Ingredients
- High Pressure Treatment of Foods
- Translational and Application-oriented Research
Our goal is the fundamental understanding of the relationships between the structures of process induced food ingredients and their molecular interactions in food as well as in the human body. Basic research currently focuses on natural food nanostructures, process induced ("secondary") food ingredients, and high-pressure food chemical reactions. In translational and application-oriented research and development projects in cooperation with industrial companies, we look for opportunities to translate basic knowledge into practical applications and new products.
Natural Nanostructurs in Foods
Nanotechnology deals with structures and materials in size ranges around 100 nm. Nature often serves as a source of ideas ("lotus effect"). Little attention is paid to the fact that nanostructured systems also occur "by nature" in food, where they play a decisive role in determining biological and technofunctional properties. Examples are the contractile proteins in muscle meat, the lipoproteins of egg yolks, casein micelles and the fat globule membrane in milk. Our research on natural nanostructures in food is currently focusing on the structure and function of casein micelles.
Caseins, the main proteins of milk in almost all mammals, are present in the form of micelles with hydrodynamic radii between 50 and 300 nm as a result of a self-association process during lactation. The exact structure of the casein micelle and the mechanisms underlying its structuring are largely unknown. In our research we investigate the structure of casein micelles of different mammals. We clarify the relevant interactions for the structure of casein micelles and establish strategies for the targeted modification of natural and artificial micelles as molecular carrier systems ("nanocapsules") of physiologically interesting compounds.
We are interested in the following questions, among others:
- How are casein micelles structured?
- How and why do casein micelles of different mammals (including Homo sapiens) differ?
- What is the function of casein micelles in the overall "milk" system?
- Can casein micelles be specifically modified by enzymatic or non-enzymatic processes and used as molecular carrier systems ("nanocapsules")?
Selected publications on this topic:
Partschefeld C., Schwarzenbolz U., Richter S., Henle T. (2007). Crosslinking of casein by microbial transglutaminase and resulting influence on the stability of micelle structure. Biotechnol. J. 2, 456-461. Fulltext
Menendez O., Schwarzenbolz U., Henle T. (2009) Reactivity of microbial transglutaminase to αs1-, β- and acid casein under atmospheric and high pressure conditions. J. Agric Food Chem. 57, 4177-4184. Fulltext
Heber A., Paasch S., Partschefeld C., Henle T., Brunner E. (2012). 31P NMR investigations of caseins treated with microbial transglutaminase. Food Hydrocolloids 28, 36-45. Fulltext
Process Induced (secondary) Food Ingredients
Drying, fermenting, heating, storing: We practically do not eat any food in its "original state", almost all of our food is processed industrially or in the kitchen. In all these processes, complex chemical reactions take place in the food, leading to the formation of new, "secondary" ingredients. These compounds determine the aroma, color and structure as well as the nutritional value and biological properties of food.
Current research focuses on post-translational protein modifications by carbohydrates (Maillard reaction, glycation) and lipid peroxidation products (lipidation), the formation of physiologically relevant carbohydrate derivatives and bioactive peptides formed by proteolytic processes. We clarify the structure and pathways of individual reaction products, investigate their metabolism and bioactivity in vitro and in vivo, and assess their relevance for food texture.
We are interested in the following questions, among others:
- Which secondary food ingredients do we ingest daily with our food?
- How do process-induced amino acid and carbohydrate derivatives interact in the human body with enzyme and transport systems of the gastrointestinal tract, the human intestinal microbiota or the immune system?
- Has the human body adapted to the uptake and utilisation of these compounds?
- Did ingredients of thermally processed food have an influence on human evolution?
- Can processing-induced food ingredients be used as bio- or technofunctional compounds in food?
Selected publications on this topic:
Henle T. (2007). Dietary advanced glycation end products--a risk to human health? A call for an interdisciplinary debate. Mol. Nutr. Food Res. 51, 1075-1078. Fulltext
Mavric E, Wittmann S, Barth G, Henle T. (2008). Identification and quantification of methylglyoxal as the dominant antibacterial constituent of Manuka (Leptospermum scoparium) honeys from New Zealand. Mol. Nutr. Food Res. 52, 483-489. Fulltext
Hellwig M, Geissler S, Matthes R, Peto A, Silow C, Brandsch M, Henle T. (2011). Transport of free and peptide-bound glycated amino acids: synthesis, transepithelial flux at Caco-2 cell monolayers, and interaction with apical membrane transport proteins. ChemBioChem 12:1270-1279. Fulltext
De Marco LM, Fischer S, Henle T. (2011). High molecular weight coffee melanoidins are inhibitors for matrix metalloproteases. J. Agric. Food Chem. 59:11417-11423. Fulltext
High Pressure Treatment of Foods
High pressure is an alternative method of preserving food. In addition, we are mostly unaware that a large part of the biomass of our planet is under conditions of increased pressure (up to 100 MPa = 1000 bar). Pressure influences the position of reaction equilibria and can therefore have a promoting or inhibiting effect on the course of a chemical reaction. The spatial structure of proteins also changes under pressure.
So far, the high-pressure treatment of foodstuffs has mainly been investigated technically and phenomenologically (e.g. inactivation of microorganisms). Our knowledge about the course of chemical reactions under these conditions comes mainly from organic synthesis chemistry. Therefore, we are interested in the investigation of known food-relevant reactions and their physico-chemical response to a pressure increase of up to 600 MPa. Current research work concerns glycation of proteins (Maillard reaction) under high pressure.
The pressure-induced change in the spatial structure of proteins has the consequence that not only the activity of enzymes but also their substrate specificity is influenced. In addition, some proteins only become suitable substrates for enzymes through pressure.
We are currently mainly interested in the following questions:
- How do food chemically relevant reactions take place under high pressure?
- How does the reactivity of proteins and carbohydrates change?
- How do enzymes act under high pressure?
- Can high pressure be used to structure food?
- Are high pressure treated foods safe?
Selected publications on this topic:
Menéndez O, Rawel H, Schwarzenbolz U, Henle (2006). Structural changes of microbial transglutaminase during thermal and high-pressure treatment. J. Agric. Food Chem. 54, 1716-1721. Fulltext
Schuh S., Schwarzenbolz U., Henle T. (2010). Cross-linking of hen egg white lysozyme by microbial transglutaminase under high hydrostatic pressure: localization of reactive amino acid side chains. J. Agric. Food Chem. 58, 12749-12752. Fulltext
Schwarzenbolz U., Henle T. (2010) Non-enzymatic modifications of proteins under high-pressure treatment. High Pressure Res. 30(4), 458-465. Fulltext
Translational and Application-oriented Research
In cooperation with industrial partners, we work on translating basic knowledge into practical applications and new products. For companies in the nutrition industry and related sectors, we make our expertise in protein and carbohydrate chemistry available for contract, consulting and development projects.
You will find further information about our cooperation under the link"Cooperation".