Revealing the mechanisms of hydrogel formation by laccase crosslinking and regeneration of feruloylated arabinoxylan from wheat bran

• Published in: Food hydrocolloids Vol. 128; p. 107575
• Main Authors: Yilmaz-Turan, Secil, Lopez-Sanchez, Patricia, Jiménez-Quero, Amparo, Plivelic, Tomás S., Vilaplana, Francisco
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2022
• Subjects: Annan teknik; Arabinoxylan; Crystallinity; Engineering and Technology; Ferulic acid; Food Engineering; Hydrogel nanostructure; Livsmedelsteknik; Other Engineering and Technologies; Oxidative gelation; Teknik; Oxidative gelation; Crystallinity; Hydrogel nanostructure; Arabinoxylan; Ferulic acid
• ISSN: 0268-005X; 1873-7137; 1873-7137
• DOI: 10.1016/j.foodhyd.2022.107575

Feruloylated arabinoxylan (FAX) from cereal brans has large potential to generate multifunctional materials with customized macromolecular and nanostructural architectures and techno-functional properties. Here we investigate the chemical and structural mechanisms of hydrogel formation of wheat bran FAX following enzymatic crosslinking by laccase and a subsequent regeneration procedure involving freeze-drying and resuspension of the crosslinked FAX in different pH buffers, using a battery of biochemical, rheological and physical techniques. The laccase crosslinking induced the conversion of ferulic acid units into a wide diversity of dimeric forms, leading to an increased molecular weight and a closer-packing of the FAX chains. The regeneration step resulted in a remarkable increase in the viscosity and viscoelasticity for all tested pH values. The amount of crystallinity of FAX increased by enzymatic crosslinking, it was however decreased by the regeneration step. The structural characterization revealed that enzymatic crosslinking, in addition to the formation of covalent crosslinks, influences the physical intermolecular interactions between adjacent FAX domains, and the regeneration forms larger clusters with higher dynamic moduli. Our results reveal that both chemical and physical mechanisms influence the network formation and multiscale assembly of wheat bran FAX hydrogels, thus modulating their rheological properties fundamental for their use in food and biomedical applications. [Display omitted] •We achieved laccase crosslinking of low substituted feruloylated AX from wheat bran.•Crosslinking increased the molar mass, viscosity, viscoelasticity and crystallinity.•Regeneration in acidic pH led to significantly stronger hydrogels.•Hydrogel rheology can be tuned by concurrent chemical and physical effects.•Combined biochemical and biophysical analyses reveal hydrogel formation mechanisms.