Technological aspects of lactose-hydrolyzed milk powder

•Lactose hydrolysis in milk promotes a greater adhesion to spray dryer.•Lactose-free milk powders have a greater tendency to browning.•Lactose-free milk powders are less soluble.•Lactose-free milk powders present modification of microstructure.•No crystals of sugar were formed in lactose-free milk powders.

Few reports describe the effect of lactose hydrolysis on the properties of milk powder during production and storage. Hence, the aim of this study was to evaluate the effects of five different levels of enzymatic lactose hydrolysis during the production and storage of milk powder. As the lactose hydrolysis rate increased, adhesion to the drying chamber also increased, due to higher levels of particle agglomeration. Additionally, more brown powder was obtained when the lactose hydrolysis rate was increased, which in turn negatively affected rehydration ability. Using Raman spectroscopy, crystallization of the lactose residues in various samples was assessed over 6 weeks of accelerated aging at a room temperature environment with 75.5% of air moisture. Products with 25% or greater lactose hydrolysis showed no signs of crystallization, in contrast to the non-hydrolyzed sample.

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