The relationship between electricity and magnetism is called electromagnetism.
Taste bud receptors if not stimulated are normally polarized. With the presence of the food, chemicals from the food bind with the cell protein which depolarized the cell membrane receptor. Depolarization will lead into the propagation of electric impulse. This will lead into the creation of sensory impulse. The larger number of the chemicals in the food will lead into a stronger impulse.
I THINK it's Carbohydrates and cholesterol. I couldn't find a very clear answer.