I sometimes use Vitamin C in recipes to give a tart taste like lemon, tomato, or sharp cheese. If you don’t have it, you can substitute lemon juice.
Pure Vitamin C is the #1 most common vitamin supplement. Also called pure Ascorbic Acid, you can buy it in any grocery in the supplement section. Look for pure white Vitamin C with no other added ingredients. Both crystals and powder are very easy to use and dissolve instantly in water. Be careful, as not all Vitamin C products are pure Ascorbic Acid. Many are made of Calcium Ascorbate which does not work and has a bitter taste.
Vitamin C has many health benefits as an anti-oxidant, anti-histamine, and an aid to the immune system. Heating destroys the beneficial qualities of Vitamin C, however heating does not affect the flavor. If you eat too much un-buffered Vitamin C on an empty stomach, it may cause temporary indigestion, so go easy.