Advances in Food Science and Technology

Advances in Food Science and Technology | Vol. 14, No. 8, August 2026 | pp. 001–006

ISSN: 6732-4215

Article Type: Review Paper

Title: Subcritical Water Extraction of Bioactive Polysaccharides from Marine Macroalgae: A Technical Review

Names of Authors: Liam O'Donnell¹, Mei-Ling Wang²

Authors’ Affiliations: ¹School of Food Science, Trinity College Dublin, Dublin, Ireland; ²Department of Biochemical Engineering, National Taiwan University, Taipei, Taiwan

Abstract: Marine macroalgae species represent abundant sources of functional structural polysaccharides, including fucoidan, laminarin, and alginate components that exhibit prebiotic benefits. However, isolating these intracellular compounds using traditional solvent extractions demands long processing durations and utilizes toxic chemicals. This technical review summarizes recent breakthroughs in subcritical water extraction (SWE) protocols deployed for marine macroalgae matrices over the past six years. We evaluate the core thermodynamic modifications that take place when water transitions under pressure between 100 °C and 300 °C, focusing on the decrease in dielectric constant variables that mimic organic solvents. The compiled datasets aggregate information across 42 peer-reviewed studies. The synthesis demonstrates that SWE speeds up extraction rates by up to 10x while maintaining polysaccharide bioactivity without degradation. However, controlling operational temperatures remains critical, as exceeding 220 °C triggers unwanted Maillard reactions that alter extract purity levels. This paper outlines industrial scale-up challenges and design criteria for continuous flow extractors.

Keywords: Subcritical Water, Marine Macroalgae, Polysaccharides, Green Extraction, Dielectric Constant, Structural Integrity

Manuscript Timeline: Received: January 12, 2026; Revised: February 22, 2026; Accepted: April 02, 2026; Published: August 14, 2026

Citation: O'Donnell, L., & Wang, M. -L. (2026). Subcritical Water Extraction of Bioactive Polysaccharides from Marine Macroalgae: A Technical Review. Advances in Food Science and Technology, 14(11), 001–006.

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