Degradation and solubilization of pectin by β-galactosidases purified from avocado mesocarp

Three β-galactosidase (EC 3. 2. 1. 23) isozymes were purified from the mesocarp of ripe fruit of Persea americana Mill. cv. Lula. and their effects on pectin derived from mature-green tomato fruit were investigated. The β-galactosidases had pl values of 5. 0,5. 1 and 5. 2. and molecular weights of 41. 49 and 54 KDa. respectively. There was a partial degradation of pectin resulting in the release of monomeric galactose upon treatment with avocado β-galactosidase. This degradation resulted in increased pectin solubility and decreased apparent average molecular size as determined by microfiltration and gel permeation by high-performance liquid chromatography. The increase in solubility was due. in part. to an apparent decrease in the ability of pectin molecules to aggregate together.