Flaxseed mucilage powder: Influence of drying methods and maltodextrin on physicochemical properties

In this study, flaxseed mucilage was extracted using distilled water as a green solvent and dried by spray-drying and freeze-drying, with and without added maltodextrin (control). The extraction process was optimized using response surface methodology, with seed-to-water ratio (1:30-1:8), temperature (20 °C-90 °C), and time (30-120 min) as variables. Responses included gel yield, dry matter, and °Brix. Optimal extraction conditions (90 °C, 120 min, 1:8 ratio) yielded the highest dry matter and °Brix values, and this mucilage was used in drying experiments. Mucilage solutions with maltodextrin (dextrose equivalents 5-7 and 18-20) and control samples were dried and characterized. Powders were evaluated for moisture content, density, flowability, solubility, particle size, color, viscosity, thermal properties, and microstructure. The freeze-dried control had the lowest moisture content (p < 0.05). Maltodextrin significantly increased bulk density (p < 0.05), with no significant difference obtained associated with dextrose equivalent levels (p > 0.05). Freeze-drying improved solubility, while spray-dried powders had smaller particle sizes compared to freeze-dried powders. Scanning electron microscope images exhibited the presence of larger particles in freeze-dried powders.