Abstract: The major components of instant soluble Peng gray were analyzed and its effect on dough extensibility was also studied by determining rheological properties, sulfhydryl groups, disulfide groups and electrophoretic analysis. The results showed that Peng gray was composed of 16.05% reducing agent Na2S, 37.73% soluble carbonate, 26.2% Na and 0.022% K. The soluble carbonate was mainly composed of Na2CO3 as well as 1.15% NaCl. The sulfhydryl groups in dough were increased as the addition of Peng gray. Meanwhile, the addition of Peng gray also resulted in RVA profile change of wheat starch. Finally, the electrophoresis result indicated that the reducing capability of Peng gray could result in the increase of low-molecular weight subunits in dough. Therefore, this study will provide a scientific basis for improving the productivity and quality of pulled noodles.

Key words: instant soluble Peng gray, extensibility, sulfhydryl, subunits