Bromelain, also known as pineapple enzyme, is a sulfhydryl protease extracted from pineapple juice and peel. Light yellow amorphous powder, slightly specific odor, molecular weight 33000. The optimum pH value for casein, hemoglobin and BAEE is between 6.0 and 8.0, and the optimum pH value for gelatin is 5.0. Enzyme activity is inhibited by heavy metals.

Slightly soluble in water, insoluble in ethanol, acetone, chloroform and ether. It preferentially hydrolyzes the peptide chain on the carboxyl side of basic amino acids (such as arginine) or aromatic amino acids (such as phenylalanine, tyrosine). It can decompose muscle fibers, but has a weak effect on fibrinogen, which can be used for beer clarification, medicinal digestion and anti-inflammation.