Exploitation of buckwheat sourdough for the production of wheat bread

Abstract

This study investigates the exploitation of buckwheat sourdough for the production of wheat bread. The fermentation induced extensive hydrolysis of buck- wheat main storage proteins, but did not influence the total protein, starch and polyphenols content of buckwheat. Buckwheat sourdough was incorporated at 10 and 20 % (w/w) in wheat dough, and control doughs were produced with the addition of a chemically acidified (CA) buckwheat batter. The addition of buckwheat sourdough greatly affected the rheological properties of the dough, by inducing a strengthening of the gluten network and decrease in elasticity. The acidification of wheat dough also stimulated the baker's yeast activity during proofing, resulting in higher release of CO2 in shorter times (volume of CO2 released (ml), control dough, 1,671.5; dough with 10 % sourdough, 2,600; dough with 10 % chemically acidified dough, 2,715.5). The properties of wheat bread were enhanced by the addition of 10 % buckwheat sour- dough, which led to higher specific volume (control, 3.41 ml/g; bread with 10 % sourdough, 4.03 ml/g) and softer crumb (crumb hardness, control, 5.28 N; bread with 10 % sourdough, 3.93 N). On the other hand, the higher acidification level did not influence the bread volume, but slightly hardened the crumb (crumb hardness, bread with 20 % sourdough, 7.41 N; bread with 20 % chemically acidified dough, 6.48 N). The fermentation positively influenced the nutritional properties of buckwheat flour and wheat bread, in terms of polyphenols (control bread, 8.84 mg GAE/100 g; bread with 10 and 20 % sourdough, 17.83 and 18.20 mg GAE/100 g, respectively) and phytic acid contents. Incorporation of buckwheat sourdough also led to an extension in the shelf life of wheat bread, which became more evident for the higher addition level. Overall, the results of this study suggest that buckwheat sourdough represents a suitable tool for enhancing the overall quality and nutritional properties of wheat bread.