Comparative Evaluation of Drying‐Induced Changes in Selected Edible Brown Seaweed Powders

This research assessed the impact of oven drying (40°C, 50°C, and 60°C) and freeze‐drying on the drying characteristics, nutritional makeup, functional traits, color, and microstructure of Sargassum wightii , Zonaria variegata , and Padina boergesenii . Moisture extraction occurred primarily during the falling‐rate phase, and the Midilli–Kucuk model accurately represented the drying kinetics, with high R 2 values (0.9965 to 0.9978). Fresh samples had elevated moisture content (79.05 ± 0.55% to 88.02 ± 0.53%), which dropped to below 9% after drying. Freeze‐dried samples exhibited the least residual moisture (7.88 ± 0.11% to 7.98 ± 0.13%) and demonstrated superior retention of protein, pigments, and rehydration characteristics. The protein content in freeze‐dried Sargassum wightii was 21.96 ± 0.24%. In contrast, the levels of fucoxanthin and chlorophyll were relatively higher (ranging from 2.34 ± 0.06 to 2.84 ± 0.08 mg/g DW and reaching up to 4.34 ± 0.11 mg/g DW, respectively). The freeze‐dried samples exhibited the highest rehydration ratios (5.18 ± 0.13 to 5.64 ± 0.15). In comparison, drying in an oven at 60°C enhanced techno‐functional attributes, including water absorption capacity (3.42 ± 0.15 to 3.82 ± 0.18 g/g), swelling power (6.36 ± 0.30 to 7.06 ± 0.34 g/g), and dispersibility (80.24 ± 2.82%). Color analysis and microscopic examinations showed increased structural collapse and pigment deterioration in oven‐dried samples, while freeze‐drying preserved a more porous and intact structure. In general, freeze‐drying proved to be superior for maintaining nutritional and structural quality, whereas moderate oven drying improved functional traits beneficial for food and nutraceutical uses.