Study on the reduction of acrylamide in mixed rye bread by fermentation with bacteriocin-like inhibitory substances producing lactic acid bacteria in combination with Aspergillus niger glucoamylase

This study mainly focuses on a strategy for reducing of acrylamide in cereal products, predominantly in bakery products. The effect of mesophilic lactic acid bacteria (LAB) strains as well as a novel fermentation media on the bases of extruded rye wholemeal on the acrylamide formation in mixed rye bread of different weight of loaf was studied. The LC-MS/MS method for acrylamide determination in bread crumb has been applied. Addition of 15% low pH (pH 3.4-4.3) fermented product to bread dough, which were produced by using commercial strain Lactobacillus casei and bacteriocin-like inhibitory substances (BLIS) producing strains Lactobacillus sakei KTU05-6, Pediococcus acidilactici KTU05-7 and Pediococcus pentosaceus KTU05-8 separately, caused significant reduction of acrylamide in mixed rye bread. All bread loafs of 1000 g contained less by 27% acrylamide concentrations versus loafs of 500 g. Acrylamide formation was affected (r2 = 0.7193) by total reducing sugar content in bread and slightly correlated (r2 = 0.5587) with reducing sugar content in sourdough. The treatment of extruded rye wholemeal with Aspergillus niger glucoamylase as compared to the control sample was found to have a positive effect on the acidification process lowering the acrylamide formation on an average by 59.4% and 40% in 500 g and 1000 g loafs of bread, respectively. This study demonstrates that acrylamide content could be reduced by using LAB excreting lower amylolytic activity in the medium, while the higher proteolytic activity is preferred.

► The large loafs of bread are proposed for bread making because of lower formation of acrylamide. ► LAB excreting lower amylolytic activity in the fermentation medium are related to the reduced acrylamide content in the bread crumb. ► Lactic acid bacteria excreting higher proteolytic activity are preferred for bread making.