Sour and spicy stimulate the immune system

Our saliva is known to play a fundamental role in food intake. He is also the first barrier against invading pathogens from the outside. Therefore saliva contains various antimicrobial substances. The composition of saliva is influenced by age, health but also by what someone eats and drinks. However, little is known about the effects of individual food ingredients. Now a team of scientists from the Leibniz Institute for Food Systems Biology at the Technical University of Munich (TUM) has found in a human study that citric acid and pungent 6 gingerol from ginger stimulate the molecular defenses in human saliva. The influence on the salivary composition of:

• Citric acid (sour),
• Aspartame (sweet),
• so-alpha-acids (bitter),
• Sodium glutamate (umami),
• Common salt (salty),
• 6-Gingerol (spicy) as well
• the substances contained in the Szechuan pepper, hydroxy-alpha-sanshool (tingling) and hydroxy-beta-sanshool (numbing)

The scientists were able to demonstrate that all the substances investigated modulate the protein composition of the saliva to a greater or lesser extent. The citric acid-induced changes increased lysozyme levels in saliva by up to 10 times. Lysozyme is an enzyme that destroys the cell walls of bacteria. 6-Gingerol increased the activity of an enzyme, which tripled the amount of antimicrobial and fungicidal hypothiocyanate in saliva.

"Our findings show that taste-giving substances have biological effects already in the mouth that go far beyond their known sensory properties," says Professor Thomas Hofmann of the TUM. These findings may well be suitable to expand the own recipe repertoire - for example, in dishes of Chinese cuisine, in which both lemons and ginger play a major role.

Rüdiger Lobitz, www.bzfe.de