A capillary-type viscometer was used in a twin-screw extruder to measure the apparent viscosity of cooked-extruded wheat-flour dough with various ingredients: lecithin, palm oil, sucrose, whey, sodium chloride, and bran. The effects of concentration of these ingredients on dough rheology and physical properties of extrudates (apparent density, expansion ratios, mechanical, and crispness properties) were measured. The role of ingredients was discussed in terms of their physico-chemical effect on biopolymer conversion. The correlations between apparent viscosity of dough and physical properties of extrudates were developed.

No abstract