Dutch-based contract research organisation Nizo food research claims to have taken the cold gelation method a step further, opening the way to control stability, gel strength and flavour conservation of heat induced gels.
Gelation of proteins is important to give food products, such as yoghurt-desserts, desirable textures. On an industrial scale, gelation is often induced by heating the final product. According to Nizo, this has three main disadvantages. Firstly, a sub-optimal use of protein-ingredients since not all proteins (usually between 50 and 80 per cent) form aggregates that contribute to the gel strength. Secondly, the final texture is hard to predict and control and finally, delicate flavours are heated and sometimes destroyed.
The research body suggested this week that cold gelation offers an alternative to overcome these problems. Under the aegis of WCFS, Nizo food research has further developed the cold gelation method that is based on separating the protein aggregation (heat) and gelation steps that are intertwined in traditional heat-set gels.
Aggregation is induced in a pre-heating step that makes it possible to fully denature the protein ingredient before gelation sets in. This ensures that all of the protein - more than 95 per cent - contributes to the gel. Gradual acidification of the solution of aggregates to form a gel at ambient temperature comprises the second step of the cold gelation method .
A large part of the research has focused on the relations between the properties of the protein-aggregates and the mechanical properties of the gels. One important conclusion, writes Nizo, in this respect is that the presence of thiol groups, that allow formation of disulphide bonds during the second acidification step, is of crucial importance for the final gel hardness.
Finally, heat-sensitive flavour compounds can now be added to a solution that does not require additional heating to form product in which the final gel properties can be precisely controlled.
Food manufacturers can use the cold gelation method for dairy products such as yoghurt desserts, or processed fish such as surimi, and for the encapsulation of probiotics.