Mitigation of acrylamide formation during malt processing

Abstract

In this study, addition of asparaginase and glycine were tested for mitigation of acrylamide in roasted malt. Free asparagine and reducing sugars increased during germination of barley. Increasing the roasting temperature increased rate of acrylamide formation and browning in malt. Application of asparaginase (3000 and 4000 ASNU/kg) and glycine (3000, 4000 and 5000 ppm) on green malt before kilning had a limiting effect on acrylamide formation at high roasting temperatures. Acrylamide levels decreased around 32% by application of asparaginase at the level of 4000 ASNU/kg. Acrylamide levels decreased around 22% by the application of glycine at the level of 5000 ppm. With the application of enzyme and glycine in combination, the decrease in acrylamide was around 50%. The colour of dark roasted malt samples was not affected from asparaginase treatment; however, application of glycine caused darker colour, probably due to the increased rate of the Maillard reaction. Overall, the results indicated that dark roasted malts with significantly lower acrylamide content can be produced by using asparaginase and glycine treatments.