For many people, sweets such as chocolate, biscuits and meringue are part of the Christmas season. But the trend is also moving towards vegan treats that are healthy and sustainable. However, when it comes to baked goods in particular, it can be difficult to completely avoid animal products such as eggs. Researchers at the Fraunhofer Institute for Process Engineering and Packaging IVV in Freising want to change that. In the ‘LeguFoam’ project, a team led by Maike Föste has developed a plant-based alternative to traditional egg whites from hens' eggs.

Protein foam from legumes as an egg alternative

The focus was on the production of a vegan protein foam that makes baked goods such as meringue, sponge cakes or cake bases light and fluffy. In their search for an egg alternative, the Fraunhofer researchers focussed on pulses such as lupins, peas and lentils – and especially their plant-based proteins. The aim was to develop a protein concentrate from legumes which, according to the researchers, can be used as an egg substitute ‘with improved foaming and stabilising properties’ for foam-based foods such as meringue.

Finally, pea flour was used to produce the egg foam alternative. ‘When processed correctly, peas have a very neutral flavour and are therefore very suitable,’ explains Föste. However, there were a few hurdles to overcome before stable pea foam was achieved. For example, the protein concentrate first had to be extracted from a mixture of flour and water. These proteins were then dissolved using lye and further concentrated using special separation processes. 

Legume proteins functionalised and optimised

In the next step, the pea protein was analysed for its ability to form foam and remain stable as such for a long time. Foam consists of air bubbles on the interfaces of which the proteins form a film, making them stable. According to the researchers, it was important for the functional protein groups to dock to the bubbles in the best possible way so that a lot of foamy mass is formed, which keeps the foam stable. According to the researchers, homogenisation under high pressure enabled them to specifically functionalise the protein structure and control the ability to form foam.

Flavour convinces gourmets

Tests on the consistency of the foamy mass showed that the ‘foam remained in a container of a defined size for a set period of time’. ‘In the meantime, our process technology with the legumes comes quite close to the quality of animal protein foam,’ reports Föste. However, the pea foam can not only keep up with the quality of animal protein. In initial sensory tests, the plant-based alternative also impressed gourmets and lovers of sweet pastries in terms of flavour, although differences to the animal model were certainly noticed.

The next step for the Fraunhofer team is to further improve the long-term stability of the pea foam. However, the team is convinced that the plant-based protein foam could serve as an egg alternative and open up new opportunities for manufacturers of confectionery and baked goods in particular to meet the growing demand for vegan products.

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