Alginate gels: I. Characterization of textural attributes

The effect of variables, such as, concentrations of sodium alginate (0-3%) and calcium chloride (0-2%), pH (2-5) and temperature (0 40 degrees C) on the textural attributes of algin-calcium gel has been studied by employing response surface methodology. An experimental design consisting of these four variables with five levels each is used. The two-cycle compression testing is conducted to determine hardness, cohesiveness and springiness that are also interrelated with sensory attributes using the method of hierarchical tree clustering. Textural attributes are sensitive to the concentrations of sodium alginate and calcium chloride, and both are essential to form a gel. The clustered group comprising instrumental cohesiveness and springiness, and sensory cohesiveness and hardness forms a group with a high similarity of more than 85% while instrumental hardness is an outlier with least closeness with other textural parameters. The optimum condition to form a gel with high cohesiveness is with 2.1 % sodium alginate, pH of 5, temperature of 37.6 degrees C and 1.1 % calcium chloride. (C) 2007 Elsevier Ltd. All rights reserved.