Optimising product quality and process control for powdered dairy products

Conventional and alternative concentration processes in milk manufacturing: a comparative study on dairy properties

“…One single stage: 4900 kJ/kg water evaporated; two stages: 4300 kJ/kg; three stages 3400 kJ/kg (Ramírez et al, 2006;Schuck et al, 2015;Verdurmen & Jong, 2003) -Reduction of the product volume;…”

“…The usual process of drying in dairy industries is spray drying and, by definition, is a transformation of feed from a solution, suspension, or paste into a concentrated/dried form by spraying this fluid into a hot drying medium (Verdurmen & Jong, 2003). To improve the thermal efficiency of the drying procedure and avoid overheating of powder particles, the equipment (spray dryer) can consist of one, two, or three stages (Figure 2).…”

“…Drying is responsible for up to 15% of the industrial energy requirement and, if compared to a concentration by evaporation, the energy demand by the spray drying process is 10-20 times higher per kilogram of water removed (Table 1). Consequently, it is usual to proceed with a primary concentration by evaporation before drying, however, spray-drying is still the most energy-intensive process in dairy industries and has received much attention (Ramírez et al, 2006;Schuck et al, 2015;Verdurmen & Jong, 2003).…”

“…The atomized feed solution meets the hot drying air and occurs the solvent evaporation, which occurs simultaneously with the cooling of the air. The concentrated product is converted into droplets of 10-200 µm and depending on the dimensions of the spray-dryer, the residence time of the dried particles is around 5 to 30 s (Schuck et al, 2015;Verdurmen & Jong, 2003). Most powder particles fall to the bottom of the dryer and are submitted to a pneumatic transport and an immediate cooling system, which is essential to preserve better flavor, physicochemical characteristics, and long shelf life.…”