Development of an Integrative Process for the Production of Bioactive Peptides from Whey by Proteolytic Commercial Mixtures

The aim of this work is to develop an integrative process based on the use of an ion exchange resin for the enzymatic hydrolysis of -lactoglobulin to produce peptides with angiotensin converting enzyme (ACE) inhibitory activity using whey as a feed stock. Unlike the conventional methods, the main advantage of this approach is that by integrating the selective separation of -lactoglobulin from whey and its hydrolysis less complex mixtures of peptides are produced. Furthermore, peptides of similar charge as -lactoglobulin remain adsorbed achieving further purification. In this work, the enzyme protease N Amano at an enzyme to substrate ratio of 1/100 (wt/wt) was added directly to the adsorbed proteins in a thermostatically controlled membrane reactor operated in batch mode. Separation of the smaller peptides from the enzyme and larger peptides was achieved with a 1 kDa molecular weight cut-off ultrafiltration membrane. Also, this step enables the recycling of non-hydrolyzed substrates, large peptides, and enzyme. The adsorbed protein was re-solubilised in a 10 mM potassium phosphate buffer (pH 7 and 45°C). The different fractions were assayed for their bioactivity in terms of angiotensin converting enzyme inhibition percentage (ACEi%) and IC50 which is the concentration of peptides that can inhibit the ACE activity by 50%. Results show that permeates of 2 and 6 hrs hydrolysis have the highest bioactivity with IC50 = 67 and 98 µg/ml respectively.