Sugar-containing derivatives formed by condensation of the hydroxyl group of glycoside monosaccharide hemiacetal with the hydroxyl group, amino group or sulfhydryl group of another molecule (such as alcohol, sugar, purine or pyrimidine). Also known as glycoconjugates. Hydrate is produced by dehydration of hemiacetal hydroxyl group of monosaccharide or oligosaccharide and hydroxyl group, amino group or sulfur hydroxyl group in another molecule. So a glycoside can be divided into two parts. One part is sugar residue (sugar removes hemiacetal hydroxyl), and the other part is ligand (non-sugar part). The ligand part can be very simple or very complicated. Glycosides are widely distributed in roots, stems, leaves, flowers and fruits of plants. Most of them are colored crystals, which are soluble in water. Generally bitter. Some are highly toxic. When hydrolyzed, sugars and other substances are produced.

Sugar ether, also known as molasses and orange water, is a by-product of sugar industry. It is a viscous, dark brown and semi-fluid object. Its composition varies with different sugar raw materials and processing conditions, and it mainly contains a lot of fermentable sugar (mainly sucrose), so it is a good fermentation raw material.