Very recently, Gigl et al. and Gabler et al. showed that the binding activity of odorants strongly depends on the composition of the HMW fraction. (31,48) For example, interaction studies with furfurylthiol as well as pyrazines before and after alkaline hydrolysis experiments showed a correlation between the release of hydroxycinnamic acids (e.g., caffeic-, ferulic-, p -coumaric acid) and the binding affinity of the odorants.