A novel approach to isolation of β-casein from micellar casein concentrate by cold microfiltration combined with chymosin treatment
Jasper M. van der Schaaf, David Goulding, Christophe Fuerer, Jonathan O’Regan, James A. O’Mahony, Alan L. Kelly
Abstract
Filtration is frequently employed in the dairy industry to tailor protein profiles and manipulate the nutri- and techno-functionality of ingredients. One milk protein of particular interest in infant formula is β-casein. However, during the enrichment of β-casein, co-fractionation of κ-casein, as 2–10% of the total protein, is common. In this study, isolation of β-casein from micellar casein using filtration, incorporating chymosin-treatment, was investigated. At 5 °C, casein curd formation can be avoided, allowing the fractionation of liquid streams. Three treatments with chymosin were applied: feed without treatment and feed or permeate treated with chymosin. An average β-casein enrichment of ∼90% (w/w) total protein was achieved. Treatment of feed with chymosin resulted in caseinomacropeptide (CMP)-enrichment. CMP-enriched β-casein showed a wider particle size distribution at 50 °C, and a reduced level of solubility. The novel materials produced may be relevant in applications such as encapsulation, emulsification, infant formula and cheese manufacture.