PROTAX – Enzymatically induced protein-AX networks in glutenfree systems

• Applicant: Professor Dr.-Ing. Mario Jekle
• Subject Area: Biological Process Engineering ; Food Chemistry
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 493413680

Gluten free (GF) recipes do not match the unique baking performance of wheat, although strong research efforts have been made in the past few years. The most comparable bread quality is gained with rye, which is attributed to its main components arabinoxylans (AX), proteins (mainly gluten) and starch and their interaction. To replace gluten, addition of multiple additives is essential for producing qualitative acceptable GF breads, of which HPMC, a chemically modified cellulose derivate, shows superior performance. Natural hydrocolloids have shown a moderate or only low improvement of GF dough systems. Novel research revealed that arabinoxylans (AX) could imitate the gluten-network to a limited degree because of its cross-linking ability through ferulic acid residues.Cereal-based proteins and AX are suitable substrates for oxidative cross-linking using laccase, tyrosinase or oxidase enzymes due to ferulic acid, tyrosine and in a minor degree cysteine residues. This novel kind of network will enhance the texture of gluten-free systems enabling the retention of biologically produced gas similar to gluten. The incooperation of hydrophophic proteins will have superior properties compared to carbohydrates like AX only. Oat, maize and rice were identified as promising raw material due to their high contents and quality of mentioned components. However, the mentioned properties of proteins and AX stated out that these raw materials have high potential to improve baking properties by the shown approach.An interdisciplinary approach including cereal technology (milling, fractionation), biotechnology (enzyme assisted cross-linking), physics (dough rheology), polymer chemistry and analytics will be applied to fulfill all aims. State-of-the-art methods will be used to characterize properties of cereal polymers and resulting network structures (e.g. HP-SEC, MALDI TOF MS, CLSM, NMR, etc.). Furthermore, model and applied doughs systems together with advanced statistics and modeling will help to understand complex reactions and structures involved.The concept of the project shows a multidisciplinary and innovative approach to improve GF bread. The project PENTOGLU already revealed the high potential of AX. The combination of cereal AX and proteins for building up cross-linked networks was never tested so far. Until now, only one study is known, which successfully performed oxidative cross-linking of AX and casein proteins.The joint project will be guided by the two principal investigators PD Dr. M. Jekle (TUM) and Dr. S. D'Amico (AGES). Additionally, Dr. D. Bender will assist the project. All three have rich expertise in cereal science with focus on milling and gluten-free processing. Supervision of the PhD students will be provided by PD Dr. M. Jekle (TUM) and Prof. R. Schönlechner (BOKU).

• DFG Programme: Research Grants
• International Connection: Austria
• Cooperation Partners: Dr. Stefano D' Amico; Dr. Denisse Bender