Effects of extruded wheat bran on the physicochemical properties and edible quality of stewing noodles

Abstract

Background and objectives: Adding untreated wheat bran directly to the stewing noodles will result in a poor flavor and rough taste. This study aims to improve the palatability and flavor of wheat bran stewing noodles by using extrusion treatment. Effects of the extrusion treatment on the physicochemical properties and edible quality of wheat bran stewing noodles were analyzed. Findings:The results showed that the total dietary fiber (TDF) content, insoluble dietary fiber (IDF) content and lipase activity of wheat bran decreased by 3.01%, 4.75%, and 71.49% after extrusion, respectively. In contrast, the soluble dietary fiber (SDF) content and the water holding capacity (WHC) of wheat bran increased by 64.60% and 32.08%, respectively (p < .05). The tensile strength of raw stewing noodles increased by 17.02% in the extruded wheat bran over that in the non-extruded wheat bran group (p < .05), but the breaking distance showed no significant difference. Also, water distribution and migration times (T 21 , T 22 , T 23 ) decreased significantly (p < .05) and the color (L*, a*, b*) increased significantly (p < .05) in stewing noodles after extruded wheat bran was added. Furthermore, starch granules were better encapsulated in the gluten network, visible pores decreased, and more compact network structure formed in the stewing noodles after extruded wheat bran was added. Regarding the qualities of cooked stewing noodles, the hardness, gumminess, and chewiness decreased and the amount of unpleasant volatile compounds, such as cyclohexanecarboxylic acid, acetic acid, and 2-Methylpropanoic acid were reduced in the extruded wheat bran group, compared with the non-extruded wheat bran group. Conversely, the amount of some of the pleasant volatile compounds, such as 2-Butoxyethanol, (E)−2-Hexenal and (E)−2-octenal, increased in the extruded wheat bran group. Furthermore, added extruded wheat bran to the flour improved the smoothness, elasticity, color, and taste of stewing noodles, and closely approximated the chewiness and taste of the high-gluten group.