Alterations of Calcium Alginate Gel Dispersions by High Pressure Treatment

摘要

Calcium alginate gel dispersions were obtained by mixing solutions containing sodium alginate and calcium chloride, followed by homogenization and rinsing. Pressure treatment was performed at pressures up to 400 MPa. The properties of the products were characterized by texture analysis, measurement of electric conductivity and by light microscopy. The state of the samples under pressure was observed by a modified method of a falling ball. By pressure treatment calcium alginate gel dispersions are transformed into homogeneous gels. The mechanical properties of the samples depend on the conditions of pressure treatment. Beyond a pressure of approximately 200 MPa the dispersions from a liquid with low yield stress and low viscosity. This phase transition is a fast process. Pressure treatments longer than 5 min have no visible effect on the formed gel. Pressures less than 200 MPa lead to an inhomogeneous product with a low gel strength.