Preparation and characterization of iota carrageenan spheres gelled by calcium ions

Abstract

Hydrocolloids are composed of groups of repeating molecules forming polymers. These hydrocolloids have the ability to hydrate and retain much water by formation of hydrogen bonds. This water retention capacity gives the functional properties that contribute to the stability and improvement of the sensory characteristics of a product, which has had a major impact on the food industry. In this work, it has been used iota carrageenan, a hydrocolloid extracted from red algae with thickening and gelling properties. Depending on the structure and physicochemical properties, iota carrageenan has the ability to bind calcium ions to form elastic gels. The main aim of this work is the preparation and characterization of iota carrageenan spheres gelled by calcium ions. In order to study the texture of the spheres, an instrumental method that follows the principles of texture profile analysis (TPA) has been developed. This provides information on various parameters that describe the texture of the iota carrageenan spheres. Since gelation of these spheres has many variables to consider, in this work have been set and only have studied the influence of calcium and influence of iota carrageenan. Lastly, rheological tests of gels have been conducted in order to obtain a correlation with the texture of the spheres. To develop the instrumental method, the experimental conditions affecting the test were studied and the conditions that made the results became reliable and reproducible were fixed. With the instrumental method developed, the influence of calcium in the spheres was studied and it was determined that at a certain concentration, textural parameters did not increase, ie, there was a calcium saturation in the spheres. Likewise, the influence of iota carrageenan was studied and it was found that increasing the iota carrageenan concentration increases the hardness of the spheres. As for the other textural parameters, it seems that they not depend on the influence of calcium or iota carrageenan. Finally, with the rheological study of the gels with identical iota carrageenan concentrations as the spheres, it was possible to state that there is a certain correlation. The hardness of the spheres increases when the elastic behavior of the gel increases.