Gelatin is a translucent, colorless, brittle (when dry), flavorless food derived from collagen obtained from various animal body parts. It is commonly used as a gelling agent in food, pharmaceutical drugs, vitamin capsules, photography, and cosmetic manufacturing.

Through pressure difference between the inside and outside , membrane separation can remove water, small peptides and some salt of dilute gelatin solution after generating from adsorption by resin resulting in concentration.

Membrane separation can run at room temperature without heating and phase change, only need electric energy and is easy to operate. The most important is that membrane separation can separate metal salts and small molecules so as to achieve the role of separation, purification and concentration while the gelatin has no adsorption and no degradation in the process of protein concentration (dehydration) .