They come in pairs on the left and right of your skull, namely:
1. Parotid glands close beneath your ears contribute 25% of thicker saliva with larger amount of digestive enzyme.
2. Sublingual glands under your tongue, produces 5% saliva, and
3. Submandibular glands under your lower jaw bone is a major contributor of 70%.
I laugh to think of the Chinese word "Kou-Shui" for saliva literally "mouth water" because it accurately portrays the main composition of saliva - 99.4% water. The remaining 0.6% is an assortment of ions, buffers, metabolites and...enzymes.
The enzyme I am seeking here is amylase. To explain, let me chew my favourite starch food, pasta al dente, leisurely and gradually comes a mild sweet sensation. That's because amylase in the saliva breaks down the pasta into simple sugar called maltose.
As I look at the bottle above to mentally estimate less than 0.6%, that's only a tiny amount of amylase to digest all the starch I eat for the whole day. Yes, enzymes are powerful little workers!
A health freak friend of mine says the first thing she doses after waking up every morning , mind you, is not brush teeth but to swallow her own saliva. Sounds like "free enzyme drink" to prevent constipation, eh? * Grins of the Alice in Wonderland Cat*