The Effect of Proteolytic Activity on the Technological Value of Wheat Flour from Pre-harvest Sprouted Grain

Investigations were conducted on the level of the overall proteolytic activity in flour fractions as well as fine and bruise bran, obtained from four varieties of wheat (‘Zyta’, ‘Pegassus’, ‘Sukces’, ‘Tonacja’), subjected to pre-harvest sprouting. Moreover, an analysis was conducted on the effect of pre-harvest sprouting on the functional properties of flour, determining the physical properties of gluten and dough. The analyses included a determination of crude protein, non-protein nitrogen, wet gluten, proteolytic activity and the rheologic properties of dough. The studies ended with a trial baking, with vitamin C and vital gluten added as improvers to the flour from pre-harvest sprouted grain. In all the milling fractions the overall proteolytic activity increased as result of sprouting, the highest increase being recorded for variety ‘Tonacja’. Simultaneously, in all the fractions tested an increased level of non-protein nitrogen was observed. Flour obtained from pre-harvest sprouted grain was characterised by an increased water holding capacity and the dough by poorer rheologic properties. Bread obtained from flour from pre-harvest sprouted grain was of insufficient quality. The use of improvers (vital gluten and vitamin C) as a rule resulted in favourable palatability and physico-chemical changes in bread.