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Autocatalytic multistage gel formation reaction in dairy based systems in relation to compositional factors
A multistage structure formation reaction is described in this paper that seems to be typical for the gel formation process in protein model system similar to products such as fresh cheese or processed cheese. Therefore, it was the objective of this study to identify and to assess the influencing factors driving the reaction. The effect of the fat- and protein content, rework as well as the fat globule size influenced by an upstream treatment were studied in this work in order to develop a deeper understanding of the complex reactions taking place in such systems, where the underlying reaction mechanisms are insufficiently understood so far. It is shown that a fat level of 15-20% is required for the multistage structure formation course to occur. By means of an upstream homogenisation of the fat phase and with an increasing protein content, the structure formation can be accelerated. It can be concluded that two parallel or partially sequential reactions seem to take place, inducing the formation of a finely dispersed emulsion as well as a protein network in the continuous phase, the latter one being sourced from proteins at the emulsion droplet interfaces. Compositional factors including the addition of rework affect the structure formation process, rework probably acting as a starter in an autocatalytic reaction.
Keywords:
gel, protein, fat