Changes of L-ascorbic Acid during Breadmaking Process

Abstract

As for the mechanism of dough improvement by L-ascorbic acid (L-ASA), which has reducing activity, TSEN reported that L-ASA was oxidized to dehydro-L-ascorbic acid (DHA) by the action of L-ASA oxidase during dough mixing, and that DHA was reduced to L-ASA by DHA reductase during the next fermentation step and the reduction was coupled with the oxidation of sulfhydril groups in dough. In this paper, the effect of L-ASA on the bread quality was examined as well as its fate in the course of breadmaking process. The optimum level of L-ASA as a bread improver was 2-5mg% as the basis of flour. L-ASA in dough was almost completely oxidized to DHA during the mixing process. A part of DHA was reduced to L-ASA during the following fermentation, and the dough is considered to be improved at the same time. The loss of L-ASA during baking varied with its initial level. The average loss was 80%. Therefore the role of L-ASA as nutrient supplement is considered to be insignificant.