Cereal Chem. 70:291-297   |  VIEW ARTICLE

Effects of Some Baking Ingredients on Physical and Structural Properties of Wheat Flour Extrudates.

G. H. Ryu, P. E. Neumann, and C. E. Walker. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

The effects of six baking ingredients (sucrose, nonfat dry milk, whole egg powder, shortening powder, glyceryl monostearate [GMS], sodium bicarbonate) on expansion, bulk density, breaking strength, and cell structure of wheat flour extrudates were studied. A Wenger TX52 twin-screw extruder was used to prepare extrudate samples. A one-half fractional 2[6] factorial experimental design was used to determine the effects of each baking ingredient on wheat flour processed under fixed extrusion conditions. Feed moisture content was 31%, barrel temperature before the die was 130 C, and screw speed was 400 rpm. Extrudate expansion was characterized by sectional, longitudinal, and volumetric expansion indexes (SEI, LEI, and VEI, respectively). Cell structure was analyzed with a scanning electron microscope and by counting the number of cells per unit area. The SEI and LEI were significantly affected by both sucrose and GMS (P less than 0.01). The interaction of shortening powder and GMS had significant effects on the LEI (P less than 0.01), and a sucrose-egg interaction affected the SEI (P less than 0.05). Bulk density was significantly affected by sucrose, shortening powder, and GMS (P less than 0.05). Sucrose and shortening powder had significant effects on breaking strength and cell structure.