Hydrothermal treatment for the recovery of dietary fiber

Authors: Rishabh Thakur; Harish Kumar Sharma

Book: Sustainable Food Innovations: Product Development, Packaging, and Waste Valorization

Editors: K. Prasad, S. Shekhar and H. K. Sharma

Publisher: SLIET Longowal

Publication year: 2026

Publication date: 2026-10-02

ISBN: 978-81-990304-2-8 (e-book); 978-81-990304-3-5 (hardback)

Chapter pages: 195–228

DOI: To be added after DOI registration.

Abstract

Hydrothermal treatment has emerged as a green and versatile technology to recover DF from food and food by-products. This chapter critically examines the application of hot-water, subcritical water, steam-explosion, saturated steam, and autoclaving for the recovery of DF. The use of high temperature and pressure facilitates matrix hydration and swelling, improves heat and mass transfer, disrupts non-covalent interactions, and cleavage of glycosidic/ ester linkages. Studies showed that the severity of hydrothermal treatment governs the fiber recovery, conversion of insoluble fiber into soluble fraction, and degradation into oligosaccharides. The mild hydrothermal treatment (hot-water) promotes dissolution and diffusion, whereas subcritical water and steam explosion induce extensive depolymerization and microstructural disruption in the polysaccharide matrix. On the other hand, autoclaving emerged as an intermediate treatment that combines moist heat, moderate pressure, and partial hydrolysis. In the present chapter, we summarize the research performed so far and compare the extraction yield, compositional change, and functional outcomes of the DF obtained after different hydrothermal treatments. Future studies should be performed on matrix-specific optimization of hydrothermal process conditions and its integration with other DF extraction techniques.

Keywords: Hydrothermal treatment; dietary fiber extraction; subcritical water; steam-explosion; autoclaving

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