Gluten-free cereal science

Food and Health - Gluten-free Cereal Science

Coeliac disease is one of the most common life-long disorders in the western world. It is a condition, where the body reacts to the protein fraction of gluten or related proteins. Coeliac disease sufferers have to follow a very strict diet and avoid any products, which contain wheat, rye and barley.Avoidance of these cereals leads to relief from the symptoms and significant improvement of the intestinal mucosa and its absorptive function. According to epidemiological studies 1 in 100 people suffer form the disease world-wide. Coeliac patients are not in position to eat some of the most common foods such as bread, pizzas, biscuits or to drink beer or whiskey. Due to the unique properties of wheat, it is a big challenge for food scientists to produce good quality gluten free products.

The objective of our research is to engineer gluten-free food and beverages with improved nutritional value as well as texture and flavour. This objective can only be reached if fundamental research is combined with the ultimate application.

To achieve this objective, a fundamental understanding of the raw-material, which needs replacing namely the macromolecule gluten, needs to be gained. We use methods such as cereal proteomics in combination with fundamental rheology and ultra structural analysis using confocal laser microscopy to gain an in depth understanding of these macromolecules. The main raw materials used to replace wheat flour in gluten-free products are grain such as sorghum, buckwheat, rice, teff etc. For some of these raw materials a fundamental understanding of their individual macromolecules in such a complex environment has not been performed yet. We therefore use a range of state-of-the-art methodologies such as HPLC, laser scanning microscopy, 2D electrophorsesis, fundamental rheology etc. to generate the knowledge essential to design gluten-free cereal-based products. From model studies as well as processing plant trials it becomes very soon apparent to create good quality gluten-free products, a network similar to what is found in wheat doughs needs to be created. A range of possibilities were explored in our laboratory to generate such networks between the various macromolecules. One of these possibilities is the use of protein networking enzymes such astransglutaminase. A fundamental understanding of the protein enzyme interactions is generated using thecereal proteomic approach in combination with laser microscopy and fundamental rheology. Currently the use of high-pressure technology is exploited to create a similar structure. 

Engineering of functional gluten-free raw materials

It is of vital importance for Coeliac patients are not only supplied with good quality products, they should if possible also be of high nutritional value. We have developed novel bio-processing procedures to increase the nutritional value of gluten-free rawmaterials. The process optimisation was carried using mathematical modelling based on the response surface methodology The functional compounds optimised ranged from beta glucan (prebiotic component), to antioxidants (e.g rutin) as well as minerals and vitamins.

Lactic acid bacteria and gluten-free science

Our research in the area of lactic acid bacteria has not only shown that the flavour profile of gluten-free cereal products is significantly improved, it was also possible to by specifically selecting Lactic acid bacteria with proteolysis activity to reduce possible cross contamination with gluten-containing cereals. Methods such as size exclusion HPLC and cereal proteomics were applied in this approach. Lactic acid bacteria (LAB) which produce EPS (Exopolysaccharides, which prebiotic properties) as well as LAB with antifungal properties have been successfully used. Methods applied here ranged from identification of the strains using molecular biological techniques to the isolation and characterisation of Exopolysaccharides and their impact on product texture (HPLC, fundamental rheology, ultra-structural analysis).

Proteomics applied to malting and brewing

Coeliac patients are also not in the position to consume standard beers (generally made from barley). We have therefore developed malting and brewing procedures for alternative grains such as Buckwheat. Process optimisation was performed using mathematical modelling. Analysis of the ultra structure and cereal proteomics were used to explain the changes taking place during processing. Novel rheological based methods were developed to characterise the raw materials as well as the processes. A detailed flavour analysis was performed using HPLC, GC and GS-MS. Chemometric data analysis was used to analyse the large amount of data generated in this study.

Application of the results to industry and other products

The knowledge generated during the work on gluten-free foods, particularly the work focussing on network formation is been currently applied to generate biodegradable chewing gum. A number of the products and processes have already been implemented in industry. 



Cereal and Beverage Science Research Group

School of Food & Nutritional Sciences, University College Cork, College Road, Cork Ireland