Brassica plants contain a compound called S-methyl-L-cysteine sulfoxide, that contributes to their distinctive smell.
When this compound is mixed with some people’s saliva, it is instantaneously broken down by enzymes, producing a sudden burst of foul-smelling gas in the mouth, [a] team reports in the Journal of Agricultural and Food Chemistry.
To see why some kids are more likely to turn their noses up at brassicas, Dr [Damian] Frank and his team collected samples of spit from 98 young children aged between six and eight, and one of their parents.
They mixed the saliva with cauliflower powder in a test tube, and analysed the production of gases released from each sample.
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“If the parent’s saliva produced a lot of sulfur compounds, there was a statistically significant correlation with their children as well,” Dr Frank said.
“I think it would be quite scary [for kids] if you are getting a lot of this weird sulfur taste in your mouth.”
Although the team didn’t analyse the saliva for bacterial communities in the mouths of the parents and children, Dr Frank said the finding suggested the oral microbiome played a role in this process.