Astringency is an well-known aspect (some may call it a defect) of the taste of red wine, green tea and many types of fruit (e.g. grapes, bananas, persimmon). This ‘classical’ type of astringency has been shown by research of the last two decades to be due to the effect of polyphenols on saliva. The lubrication by saliva of the contact between tongue, palate and teeth is lost, resulting in an experience which consumers call ‘rough’, or ‘sandy’, and usually considered unpleasant.
This astringency, however, emerges not only in wine and tea, but also in food in which animal proteins have been replaced by plant proteins. This type of astringency, in which polyphenols probably play only a minor role, has not been addressed much by scientific research, and measures to prevent it are therefore scarce or even absent. This demand for technological tools for making plant proteins better palatable is becoming more urgent as the protein transition gets under way.
NIZO has a leading role in astringency research particularly aimed at (novel) plant proteins. This involves testing and screening of food formulations with respect to lubrication (tribology), molecular interactions with saliva, heat treatment, extraction procedures and sensory scoring by human test panels. Most of the work takes place in collaboration with industrial parties, either one-to-one or in consortia with industry and universities. Some fundamental aspects are explored by NIZO in in-house background programs, which deliver theoretical understanding needed for an efficient search for solutions.
For further information please contact Dr. Els de Hoog or Dr. Hans Tromp.