Process for isolating beta-lactoglobulin from milk or milk fractions

摘要

The present invention is concerned with a process for isolating undenatured beta -lactoglobulin from milk or milk fractions, said process comprising the following steps: h) removing milk fat by a physical separation method; i) removing casein through precipitation at pH 4.2 to pH 4.8; j) adjusting the pH of the milk or milk fraction to a pH between 6.9 and 7.5; k)diluting with essentially ion-free water to a conductivity of less than x mS at t DEG C, where x = 5 + 0.15*t ; l) allowing the beta -lactoglobulin to bind reversibly to an anion exchange material; m) separating the bound beta -lactoglobulin from the supernatant; n) liberating the beta -lactoglobulin from the anion exchange material by rinsing with a dilute salt solution; whilst ensuring that during each of the aforementioned process steps the pH remains between 4.2 and 7.5 and the temperature between 0 and 35 DEG C. The process according to the invention enables the isolation of beta -lactoglobulin from said milk or milk fractions in essentially undenatured form In another embodiment the present invention is concerned with a dairy isolate containing at least 2.0 wt.% undenatured beta -lactoglobulin, wherein the isolate contains, in combination, less than 3 wt.% of irreversible beta -lactoglobulin dimers and/or milk proteins other than beta -lactoglobulin, calculated on pure beta -lactoglobulin.