Hydrolysis of Lactose in Milk: Current Status and Future Products

The lactose-free dairy market has significantly grown in the past years in relation to the large population who experience lactose intolerance. Lactose-free dairy products are nutritionally more attractive than alternative lactose-free non-dairy products because of the superior amino acid profile. Of the methods to produce lactose-free dairy products, lactose hydrolysis is the most economical and sustainable since there is no by-product formed in the process and offers the possibility of generating value-added products, like galactooligosaccharides. This review covers the advantages and disadvantages of techniques for hydrolyzing lactose in milk and pure lactose. Mainly, it focuses on enzymatic hydrolysis methods. Additionally, it analyzes scale-up problems with specific techniques and what future research should be conducted to generate novel products of commercial utility. Currently, pre-process hydrolysis using soluble β-galactosidase is the most common way to produce lactose hydrolyzed milk industrially while academic research focuses on immobilized packed bed reactors to recycle enzymes and produce higher yields of value-added products. Further experimental research should be conducted on developing a commercial scale immobilized enzyme bioreactor to produce more economically and environmentally attractive lactose hydrolyzed milk.