Purification of goat beta-lactoglobulin from whey by an ultrafiltration membrane enzymic reactor

This paper presents a novel contribution to the purification of goat beta-l actoglobulin by using art ultrafiltration membrane enzymic reactor. The bas is of the purification process was the enzymic hydrolysis of contaminating proteins, alpha-lactalbumin and traces of serum albumin, by pepsin at 40 de grees C and pH 2, conditions under which beta-lactoglobulin is resistant to peptic digestion. Simultaneously, beta-lactoglobulin and peptides were sep arated by ultrafiltration, beta-Lactoglobulin was retained in the reactor w hile peptides generated by hydrolysis from alpha-lactalbumin and serum albu min permeated through the membrane. The process was made continuous by the addition of fresh whey to replace the lost permeate. Three mineral membrane s with 10, 30 and 50 kDa molecular mass cut-off were tested and the 30 kDa membrane was selected for the continuous process. The simultaneous purifica tion and concentration of beta-lactoglobulin from clarified goats' whey was achieved in a single step. The ultrafiltration membrane enzymic reactor co uld treat eight reactor volumes of clarified whey. The recovery of beta-lac toglobulin was 74 %, its purity was 84 % and its concentration 6.6-fold tha t in the initial clarified whey.