Crystalline Layer Formation of Highly Viscous Supersaturated Liquids

Abstract

The handling of highly viscous supersaturated liquids during nucleation and crystal growth is an important challenge. Here, solutions mixed with hydrocolloids were tested for the formation of gelled products enclosed by a crystallized layer of sucrose from the starting liquid mixture. To create reproducible layers on the gel body, the nucleation needs to be initiated by external seed materials. The influence of the hydrocolloids on the crystallization process and therefore the crystal growth in combination with the different seeds for nucleation (starch, icing sugar) was tested and evaluated. Different external seed materials can have an influence on the thickness of the sugar layers. A significant influence on the thickness of the crystalline layers can be found by the use of different highly viscous solutions.

Analysis of Hydrocolloids in Crystalline Material

“…The measured layer thicknesses (details of the measuring methods can be seen in a previous publication from Herfurth et al [4]) confirm the model of a water loss in a crystallized sugar-hydrocolloid layer. There the layer thicknesses of products generated with 1.5 wt % agar in a starch powder bed are illustrated exemplarily.…”

“…k-Carrageen of different producers shows similar weight losses Figure 2. Measuring principle of a single-beam photometer [4].…”

“…These solutions were poured into a starch mold to start the crystallization (coating) and to shape the end products . Different methods could be developed to verify the existence of these gels in the crystallized sugar layers; see Tab.…”

“…As an example, the paper from Herfurth reports on results concerning the nucleation behavior of sugar with different external seeds. Other interesting topics are presented in the literature, e.g., or , where various effects of food additives have been described in the field of crystallization of sugars.…”

“…Methods to prove the hydrocolloid content in crystalline material can help to evaluate the purity of crystalline layers. Previous works on this topic show that the layer thickness of coated gels can be influenced by its application in sugar products. For example, the use of agar leads to thicker layers compared to a layer grown without a hydrocolloid (pure sugar).…”