Delactosed milk powders (DMP) are produced from enzymatic lactose hydrolysis and, due to presence of galactose and glucose in their formulation, these powders have higher tendency of stickiness, caking and browning during the drying process. For this reason, the production of delactosed powders is yet a challenge for the dairy industry. This work aimed to evaluated the effect of operational drying parameters (θ_air,in = inlet air temperature and M_CM = concentrated milk flow rate) on the physicochemical and technofunctional properties of DMP. Furthermore, the expenditure of energy during the drying process was evaluated from mass and energy balances. DMP was produced by both variations of θ_air,in (from 115 to 160°C) and M_CM (from 0.3 to 1.5 kg·h⁻¹) in a pilot single stage spray dryer. Powder produced at lower temperatures (θ_air,in < 145°C) and higher milk flow rates (M_CM > 1.3 kg·h⁻¹) presented elevated mass loss (~30%). Under these conditions, water was not efficiently removed from the product resulting in powders with high humidity (~11% w·w⁻¹), a_w > 0.2 and strong agglomeration to equipment. The combination of higher temperatures (θ_air,in > 130°C) and lower milk flow rates (M_CM = 0.3 kg·h⁻¹) resulted in powder with high temperature favoring the Maillard reaction in which were confirmed by presence of products as 5-hydroxymetylfurfural and brown color. In general, by working with M_CM values between 0.5 and 1.0 kg·h⁻¹ for any tested temperature, it was possible produce DMP with color, rehydration, humidity, aw and particle morphology closer to milk powder containing lactose (control). Within this group, best results were observed in the powders produced at θ_air,in = 145°C and M_CM = 1.0 kg·h⁻¹: humidity = 4.2%, aw = 0.2, light yellow color, complete rehydration, mass losses = 15% and energy losses = 22%. Even under optimal drying conditions, this DMP showed energy expenditure of 28,000 kJ·kg⁻¹. This approach is a potential tool that can be used by dairy industries to evaluate the properties and cost of delactosed dairy powders.