Influence of Human Salivary Enzymes on Odorant Concentration Changes Occurring in Vivo. 1. Esters and Thiols

Abstract

The influence of human whole saliva on odor-active esters and thiols was investigated. Special emphasis was placed on food-relevant concentrations of the odorants. It was found that the amounts of the esters were reduced during incubation with saliva to different extents according to their chemical structures. Considerable degradations were also observed for 2-furfurylthiol, 2-phenylethanethiol, and 3-mercapto-3-methyl-1-butanol, being reduced from approximately 70 to 20% of their initial concentrations within a period of 10 min. Decrease of the odorants did not occur after thermal treatment of the saliva. Generally, the enzymic processes were found to be dependent on the salivary activity of each individual panelist as well as on the odorant's concentrations applied. These investigations were aimed at finding an explanation for the persistence of aftertaste in humans, as it is induced by some odor-active compounds after the consumption of food materials.

Chemical input – Sensory output: Diverse modes of physiology–flavour interaction

“…in the development of the aftertaste of specific foods Hussein, Kachikian, & Pidel, 1983). It has also been shown that the concentrations of some odorants remain unchanged when exposed to saliva, whilst the amounts of potent thiols such as 2-furfurylthiol, which is an aroma constituent of coffee, decreases relatively rapidly (Buettner, 2002a(Buettner, , 2002b. Furthermore, Starkenmann et al found that odorants can be formed from non-odorous precursors (cysteine-S-conjugates), which are stable in aqueous solutions but decompose rapidly in the presence of saliva, thereby releasing potent thio-odorants (Starkenmann, 2003;Starkenmann et al, 2008).…”

Development of food-grade filled hydrogels for oral delivery of lipophilic active ingredients: pH-triggered release

“…Aqueous-based delivery systems containing relatively small particles do not require chewing before swallowing. Nevertheless, they are still exposed to changes in environmental conditions within the mouth that may alter their release properties, such as changes in temperature, enzyme activity, dilution, pH, ionic strength, flow profiles, and interactions (Buettner, 2002;Hansson, Leufven, & Van Ruth, 2003;van Ruth, Grossmann, Geary, & Delahunty, 2001). One or more of these factors may be used as potential triggers for the release of encapsulated active components within the mouth.…”

Sensory and molecular characterisation of human milk odour profiles after maternal fish oil supplementation during pregnancy and breastfeeding

“…On the other hand, one must bear in mind that food aromas can originate from a diversity of substance classes with a broad range of chemical reactivity (Grosch, 2001;Nijssen et al, 1996), being often heavily metabolised in vivo (Buettner, 2002a(Buettner, , 2002bBuettner, 2010;Engel, 2001Engel, , 2002Zeller, Horst, & Rychlik, 2009).…”