From the perspective of pure chemistry, functional sugar actually refers to functional oligosaccharides, functional dietary fiber, functional sugar alcohols and other substances with special physiological functions.

Among them, functional oligosaccharides mainly include stachyose, raffinose, isomaltulose, lactulose, fructooligosaccharide, xylooligosaccharide, galactooligosaccharide, isomaltooligosaccharide, gentian oligosaccharide, soybean oligosaccharide, chitosan oligosaccharide and so on. Because there is no enzyme system to hydrolyze them (except isomaltulose) in human intestine, they are not digested and absorbed.

Functional dietary fiber is a kind of high molecular carbohydrate. Because it can't be normally digested and absorbed by human body, it has no nutritional value. However, because it can't be digested, it can slow down the digestion speed, excrete cholesterol as quickly as possible, keep blood sugar and cholesterol above the ideal level, and help diabetics reduce insulin and triglycerides.

Functional sugar alcohols mainly include sorbitol, maltitol, xylitol, erythritol and isomaltulose. With the significant increase of type 2 diabetes in China, sugar alcohols as substitutes for common sugar are used more and more. Because sugar alcohol does not cause a significant increase in insulin in the body, it is added to many foods that need sweetness but must be sugar-free. However, the characteristics of sugar alcohols, such as prebiotics, low energy, hypoglycemia and hypoglycemia,