Rheological properties including tensile fracture stress of semolina extrudates influenced by moisture content
1997
Liu, H. | Hayakawa, K.
Semolina extrudates were reshaped, immediately after extrusion to form 0.5 mm thick X 2 mm wide X 130 mm long strips. Moisture content (W) was adjusted to 5 to 39% (dry basis) equilibrating in desiccators containing saturated salt solutions. The following tensile rheological properties of the prepared samples were determined at room temperature (21-24 degrees C) using a Rheometrics solid analyzer: Young modulus (E), yield stress (o-(y)), fracture stress (o-(c)) and fracture stain (epsilon(c)). Each of E, o-(y) and o-(c) was fitted by a semilogorithmically linear function of W with a negative slope. The property epsilon(c) fitted two semilogarithmically linear functions: for W < 24.2% a line with a positive slope and for W > 24.2% a line with near zero slope. Such data for moisture ranges used in conventional pasta drying can help to optimize conditions for pasta production without stress cracking.
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