Eli5: Starch and Cellulose are Polymers of Sugar, what’s the reason behind them not being sweet?

Question

Eli5: Starch and Cellulose are Polymers of Sugar, what’s the reason behind them not being sweet?

In: Chemistry

Answer 1

If glucose (or another very simple sugar) is a key that fits into your “sweet” receptor, then cellulose is like a bunch of keys welded together end-to-end. It won’t fit in that lock until the keys are separated. Some of that “unwelding” can happen in your mouth with digestive enzymes in your saliva, so that starchy foods can have a little sweetness to them. But more fibrous foods aren’t going to taste sweet because your mouth can’t break that down into simple sugars which fit your taste receptors.