Impact of Drying Techniques and Maltodextrin as a Carrier on the Flow Properties and Reconstitution Properties of Oat “milk” Powder

Oat (Avena sativa) “milk” has gained popularity as a suitable alternative for individuals following vegan diets or those with lactose intolerance, owing to its appealing taste and significant health benefits. The rising demand for plant-based “milk” alternatives, however, presents challenges related to the storage stability and shelf life of liquid oat “milk”. Converting oat “milk” into powder form addresses these issues by enhancing shelf stability, improving transportability, and increasing convenience, thereby benefiting both consumers and manufacturers. This study investigates the production of oat “milk” powder using two drying techniques: spray drying and freeze drying. Maltodextrin (MD) was used as a carrier at concentrations of 0%, 5%, and 10% in both drying processes. Oat “milk” was processed using a tall-type spray dryer with a constant feed rate of 15 ml/min, an inlet temperature of 160±1°C, and an outlet temperature of 115±1°C. In parallel, vacuum freeze drying was employed to remove moisture from the frozen oat “milk” through sublimation at -60°C, maintaining the nutritional integrity of the product. The resulting powders were analyzed for flow properties, moisture content, water activity, wettability, and solubility. The water activity of the oat “milk” powder (OMP) samples ranged from 0.33 ± 0.02 to 0.6 ± 0.01, indicating microbial safety. Moisture content differed between spray-dried and freeze-dried powders, with the spray-dried powders exhibiting higher Carr’s index values. The wettability ranged from 9.33 ± 0.6 to 16.67 ± 0.6 seconds, and solubility varied from 71.34 ± 1.09% to 88.07 ± 1.10%. Additionally, the brightness of the oat “milk” powder increased with increasing maltodextrin concentration, from 80.71 ± 0.5 to 87.05 ± 1.2. These results were used to identify the optimal dehydration technique based on the physicochemical properties of the powder. The oat “milk” powder produced in this study demonstrates potential for use as a substitute for “milk” powder in vegan products, premixes, chocolates, and bakery formulations.