Impact of lactic acid bacteria starter cultures and hydrolytic enzymes on the characteristics of wholegrain crackers

Abstract

This work studied the impact of bioprocessing with lactic acid bacteria starter cultures (dextran producing Weissella confusa and Lactobacillus plantarum) and proteolytic and xylanolytic enzymes on structural, chemical and sensory characteristics of wholegrain wheat crackers. Bioprocessing of flour increased free amino acids content (FAA) and water extractable arabinoxylans (WEAX). W. confusa fermentation increased FAA the most (0.46–0.48 g/100 g) compared to the control (0.22 g/100 g). Treatment with xylanase and fungal protease showed highest WEAX (2.29 g/100 g vs. 0.90 g/100 g). This cracker was also the thickest. Fermentation with W. confusa without dextran production decreased thickness, while dextran containing W. confusa samples were similar to the control. Cracker thickness and flour RVA-viscosities showed negative correlation. Non-dextran W. confusa increased final viscosity (1807 cP) and setback viscosity (1200 cP) compared to control flour (1318 cP and 885.5 cP). Both enzyme-types reduced viscosities: e.g. lowest final viscosity was 729.5 cP after protease treatment. Microscopy indicated enhanced gluten network especially after xylanase treatment. Enzyme-treated crackers had neutral flavor and soft structure, as well as increased tendency to break down in the mouth. Fermented crackers were hard and had pungent flavour. Acidification appeared to negate the possible positive impact of dextran on cracker quality.