5. Conclusions
We studied the influence of the presence of starch on wheat gluten hydrolysis. Wheat gluten in wheat flour (WFG) was hydro-lyzed at 5.6 times higher solid concentrations but at the same protein concentrations than vital wheat gluten (VWG). WFG hydrolysis at 40% solids resulted in higher DH% than VWG hydrolysisat 7.2% solids. Furthermore, higher DH% were obtained when hydrolyzing VWG with added starch, compared to VWG alone and for WFG hydrolysis compared to the washed gluten fraction of the wheat flour. This showed that differences in the gluten composition and the presence of albumins and globulins in wheat flour can not explain the difference in DH%. Instead, we concluded that starch granules facilitated the hydrolysis reaction by hindering the gluten aggregation. The final composition of the hydrolysates, though, was just a function of the enzyme used and the DH%, but not influenced by the starch. At higher solid concentrations up to 70% wheat flour,the positive effect of starch disappeared, because WFG hydrolysis was hindered by mass transfer limitations and lower water activities.The results show that the understanding and prevention of wheat gluten aggregation is important in order to improve wheat gluten hydrolysis, and could be a drive for mixer design or the use of additives other than starch.