title: Formation of fibrous materials from dense calcium caseinate dispersions.
abstract: Application of shear and cross-linking enzyme transglutaminase (Tgase) induced fibrous hierarchical structures in dense (30% w/w) calcium caseinate (Ca-caseinate) dispersions. Using Tgase was essential for the anisotropic structure formation. The fibrous materials showed anisotropy on both micro- and macroscale as determined with scanning electron microscopy (SEM) and mechanical analyses, respectively. SEM revealed protein fibers with a diameter of approximately 100-200 nm; visually, we observed fibers of about 1 mm. Both shear and Tgase affected the reinforcement of the fibers to a large extent, whereas the mechanical properties in the direction perpendicular to the shear flow remained constant. Shearing Ca-caseinate without Tgase yielded a slightly anisotropic layered structure. Both cross-linking in the absence of shear and cross-linking during mixing resulted in gels without alignment. The formation of shear- and enzyme-induced anisotropic structures was explained by aligning of protein aggregates due to shear and concurrent solidification of the aligned protein aggregates.
authors.affiliation: Food and Bioprocess Engineering Group, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands.
authors.forename: Julita M
authors.initials: JM
authors.lastname: Manski
authors.forename: Atze J
authors.initials: AJ
authors.lastname: van der Goot
authors.forename: Remko M
authors.initials: RM
authors.lastname: Boom
mesh_terms: D016880:Anisotropy; D002364:Caseins / Q000138:chemical synthesis* / Q000737:chemistry; D046911:Macromolecular Substances / Q000138:chemical synthesis / Q000737:chemistry; D008855:Microscopy, Electron, Scanning / Q000379:methods; D010316:Particle Size; D012680:Sensitivity and Specificity; D011503:Transglutaminases / Q000737:chemistry
chemical_list: D002364:Caseins; D046911:Macromolecular Substances; C484216:calcium caseinate; D011503:Transglutaminases