Effect of composition changes and aeration time on the structure and rehydration of innovative freeze-dried gels

Abstract

This paper seeks to explain the structural effect on selected properties of freeze-dried gels with different compositions and aeration times. Herein, sugars and citric acid were added to gels with low-methoxyl pectin, mixtures of xanthan gum and locust bean gum, as well as xanthan gum and guar gum, in order to obtain a strawberry model. Strawberry pulp was also added to hydrocolloids to develop an innovative strawberry product. All samples were aerated for 3 and 7 min, and freeze-dried. Composition changes were found to modify the structure of the examined samples and properties. Freeze-dried gels with low-methoxyl pectin seemed to reflect the best approach towards obtaining an innovative strawberry product with a tailored structure, as they had the best water absorbent capacity, and the most attractive and delicate structure. Samples with a mixture of hydrocolloids were more compact. Aeration time did not significantly affect the examined parameters, while the addition of sugar and citric acid increased them. The strawberry pulp experiment confirmed the strawberry model (with low-methoxyl pectin gels, and sugar and citric acid), which had the finest structure and the best rehydration properties.