Effect of Flour Extraction Rate and Amount of Asparaginase Enzyme on Reduction Free Asparagine in Bread Dough

Acrylamide, a carcinogen material, is produced in temperatures above 120 ̊C in bread. Free asparagine in wheat flour is the basic factor in acrylamide formation in bread. In accordance with its nutritional and medical importance, the aim of this study was to study the effect of flour extraction rate and asparaginase enzyme on reducing the free asparagine in bread dough.

To perform this experimental study, two types of wheat were obtained from Golestan province, and two kinds of flour were produced with 93% and 82% extraction rate by mixing the two kinds of wheat. The value of free asparagine in whole flour, bran and endosperm flour obtained from the two varieties of wheat and in two kinds of flour was determined. Then, the effect of the flour extraction rate on free asparagine and asparaginase enzyme on the hydrolysis of free asparagine in flour and the two varieties of dough was investigated in laboratory and bakery conditions. The free asparagine by liquid chromatography with high efficiency was measured, and the data were analyzed through independent t-test and Mann-Whitney.

A significant difference was observed between the means of free asparagine in whole flour, bran, endosperm flour and the two kinds of flour (p<0.05). The suitable density of asparaginase enzyme for reducing free asparagine in two kinds of dough was 500 mg/kg. Reduction of asparagine by the use of similar density of the enzyme in the two kinds of dough was not significant, 88.02% (p>0.05).

The effect of wheat variety and flour extraction rate on free asparagine value is inevitable, but using asparaginase enzyme is a useful way to reduce asparagine in bread dough.