I work at Stratagene - I am in charge of the educational kits. One of
the kits I have is a salivary enzyme kit.
Bring your amylase or invertase up in 10 mm Potassium acetate or
sodium acetate (I've found they work in either), bring your substrate
up in water.
If you need more help, let me know. If you'd like more information
about my education kits, just email me back with your address and I'll
be happy to keep you informed.
Educational Kits Division
Stratagene Cloning systems