Thin‐Layer Drying Kinetics and Bioactive Compound Retention in Saccharina latissima: Implications for Scalable Seaweed Processing

Drying is a critical preprocessing step for stabilizing seaweed biomass and shaping its functional quality for food, nutraceutical,and biorefinery applications. This study evaluated the drying behavior of Saccharina latissima under oven drying (OD), airdrying (AD), and freeze drying (FD) by combining thin-layer kinetic modeling and the analyses of phytochemical compositionand antioxidant activity. The three methods exhibited distinct drying behaviors where OD showed rapid moisture removal,reflected by the highest drying constant and effective diffusivity, driven by high vapor pressure gradients and strong internaldiffusion. AD proceeded slowly under low-temperature, low-convection conditions, exhibited by its slow kinetics and lowestdiffusivity. FD followed a two-stage pattern characterized by fast sublimation during primary drying and slower desorption ofbound water during secondary drying. These behaviors were reflected in model performance, with the Lewis model bestdescribing OD, the Page model for AD, and the logarithmic model for FD. These differences corresponded to distinctcompositional outcomes, wherein OD yielded the highest total polyphenol and flavonoid contents and antioxidant capacity,while FD preserved moderated levels and AD yielded the lowest. This study establishes process–structure–functionrelationships linking drying mechanisms with bioactive compound recovery in S. latissima, providing a framework for selectingand optimizing drying strategies in seaweed processing.