Sprouted wheat: a new ingredient in bread-making?

Sprouting (also called germination) is an ancient method associated with improvements of the nutritional and sensory properties of cereals and pulses (Hübner & Arendt, 2013). The other side of the coin is flour functionality. Indeed, when grains are exposed to prolonged wet or foggy conditions, severe and uncontrolled grain sprouting may occur, inducing high accumulation of enzymatic activities that negatively affect dough rheology and baking performance. Thus, using of sprouted grains in baking has been restricted until now. Partial germination – i.e. sprouting carried out in controlled conditions of moisture and temperature – has been recently proposed as a new process to balance the nutritional properties and technological performance of chickpeas-enriched dough (Marengo et al., 2017). Whereas limited information is available on the effects of partial germination on wheat and the potential application of flour and/or bran in bread-making. The present work is divided in three parts. The first part addressed the possibility of using refined flour from sprouted wheat (SWF) to improve the bread-making performance of some flours in place of conventional improvers - i.e. enzymatic improver (EI) and malt (M). SWF showed increased enzymatic activities without compromising the aggregation properties of gluten proteins. Dough development increased, thanks to the enrichment with 1.5% SWF, whose presence also improved the amount of gas production during leavening- resulting in bread with high specific volume - and crumb softness during storage. The second part of the work addressed the effects of high levels of SWF (from 15 to 100%) on dough rheological properties and baking performance. Adding SWF to flour significantly decreased the dough water absorption, development time and stability during mixing, while the degree of softness increased, suggesting gluten weakening. However, no significant changes in mixing properties and gluten aggregation kinetics were measured between 25-75% SWF. Regardless the level of addition, SWF improved the dough development and gas production during leavening. The decrease in gas retention did not compromise bread-making performance. The best result – in terms of bread volume and crumb porosity – was obtained with 50% SWF instead of using SWF alone. Interestingly, controlling the sprouting process was also possible to control starch digestibility. Finally, the related bran (B_GERM) was added to flour at 20% level. The effect of bran-enrichment on dough rheological properties and bread-making performance was assessed and compared with that of bran from control wheat (B_CTRL). When B_GERM was added to flour, dough water absorption and its stability significantly decreased. B_GERM improved dough leavening by decreasing the proofing time from 161 min to 131 min (for B_CTRL and B_GERM, respectively), without compromising gas production and dough development. Compared to B_CTRL, B_GERM improved crumb softness of the bread, even during storage (up to three days). In conclusion, either refined flour or bran from sprouted wheat could be an interesting ingredient for improving the technological performance of bread and/or fiber-enriched bread. Keywords: sprouting, dough rheology, bread- making, starch digestibility, bran References: Hübner, F., & Arendt, E. K. (2013). Germination of cereal grains as a way to improve the nutritional value: a review. Critical Reviews in Food Science and Nutrition, 53, 853–61. Marengo, M., Carpen, A., Bonomi, F., Casiraghi, M.C., Meroni, E., Quaglia, L., Iametti, S., Pagani, M.A. and Marti, A., 2016. Macromolecular and Micronutrient Profiles of Sprouted Chickpeas to Be Used for Integrating Cereal-Based Food. Cereal Chemistry, 94, 82-88.