Good gluten-free bread - a technological challenge

The chemical composition, structure and internal organisation of the building blocks of high-starch raw materials is reflected in the viscoelastic properties of the thin (paste) and thick (dough) suspensions formed from them. This characteristic is crucial in their further use in the formulation of food products, as it is responsible for the formation of specific food structures and textures, which are decisive quality differentiators in food products.

Coeliac disease and other gluten-dependent disease entities are associated with the consumption of allergenic glyandin proteins present in certain cereals (wheat, rye, barley) and responsible for triggering specific metabolic reactions directly or indirectly in people sensitive to their presence. The only solution for these people is to permanently eliminate these grains and their products from the diet.

Prof. dr hab. Joanna Harasym, project executor, photo. Michał Łepecki However, following a gluten-free diet is not an easy task, as gluten-containing grains, especially wheat, are the main ingredients in popular food products in Western culture, such as bread, pasta and sweet breads. Currently, the market for GF products is experiencing significant growth, mainly due to an increase in the number of diagnosed gluten-avoiding patients and the emergence of a new market niche for consumers who optionally avoid gluten.

However, the use of cereal flours from grains other than wheat in baked goods presents technological challenges due to the lack of a structural network formed by the gluten protein complex. Obtaining viscoelastic properties similar to those of wheat doughs is a prerequisite for obtaining technologically relevant and sensorially acceptable baked goods from gluten-free recipes.

It is known that thermal treatment of flours causes changes in the conformation of proteins, enzyme activity, starch solubility and antioxidant activity of the raw material, all of which result in modified viscoelastic characteristics of glutens and doughs created from flours so produced.

In the project, we analysed the effect of hydrothermal treatment assisted by electromagnetic radiation (microwave radiation – 2.45 GHz) on the change in physicochemical properties of two gluten-free high-starch plant raw materials – buckwheat (Fagopyrum esculentum Moench) and abyssinian ginkgo (Eragrostis teff).

The overarching goal of the research project was to effectively modify the functional and physicochemical properties of naturally gluten-free flours. The key idea was to take advantage of the phenomena of modifying the quaternary and tertiary conformations of natural polymers at elevated temperatures. This made it possible to modulate the viscoelastic properties of the flour components with physical factors only, without the use of chemical compounds or structure-forming additives like vegetable gums. Microwave radiation at 2.45 GHz and water, in which the oscillation of dipoles generated heat directly at the point of occurrence rather than by convection, were used for efficient heat transport.

Prof. dr hab. Joanna Harasym, project executor, photo. Michał Łepecki At the same time, it was important to preserve the nutritional values specific to the plant material used, especially those derived from polyphenolic substances and other antioxidants.

The experimental results obtained were published in several scientific articles of JCR-listed journals and presented at more than 5 international conferences. The project also enabled the building of a new platform of cooperation between young foreign researchers Dr Marina Villanueva and Dr Tetiana Lisovskaya, who successively served as the project manager. The results of the research have been presented at a number of international scientific conferences arousing interest and enabling the establishment of broad scientific cooperation.