Description of theme
Carbohydrates determine to a large extent quality attributes of the final food product while polysaccharides (e.g. pectic substances, hemicelluloses, cellulose) as present in fresh fruits and vegetables (e.g. ripeness, texture) determines their typical characteristics as well as their processing characteristics in the manufacture of foods (juices, nectars, purees, preserves). Polysaccharides also influence the extractability of important constituents of plant raw materials like sugar, oil, proteins, etc. Dietary fibers and prebiotic oligosaccharides, including mammalian milk oligosaccharides, play an important role in human and animal health, and their behaviour in the gastrointestinal tract strongly depend on the chemical structure of these fibers.
In general, various classes of oligo- and polysaccharides as present in fruits, vegetables, cereals or food products derived here from and of agrotechnological by-products are extracted and characterised by e.g.sugar (linkage) composition, substituents, molecular weight. Unknown carbohydrate structures are separated by (preparative) chromatography and characterised using mass spectrometry and NMR. Enzymatic fingerprinting methods using pure and well characterised enzymes are being used and further developed to enable ‘sequencing’ of complex carbohydrate structures using state-of-the-art LC-MS platforms. The fate of individual prebiotic and dietary fiber structure during the digestion and fermentation in in vitro models as well in human and animals are monitored using the same analytical techniques.
Relationships between the chemical fine structure of the carbohydrate under investigation and the corresponding functional property of this carbohydrate (isolated or as present in the original product) will be established.
Typical materials studied are: cereals like wheat, corm; fruits and vegetables like apple, tomato, carrots, potatoes, soybeans; food ingredient like pectin, galactomannans, xanthan, as well as human milk and fermentation digests.