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Effect of barrel temperature and screw speed on rapid viscoanalyser pasting behaviour of rice extrudate
Author(s) -
Guha Manisha,
Ali Syed Zakiuddin,
Bhattacharya Suvendu
Publication year - 1998
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1046/j.1365-2621.1998.00189.x
Subject(s) - die swell , extrusion , plastics extrusion , barrel (horology) , viscosity , materials science , extrusion cooking , composite material , food science , chemistry
The effect of extrusion barrel temperature (80–120 °C) and screw speed (200–400 rpm) on the pasting and gelatinization properties of extruded rice products were studied. A twin‐screw extruder was used without using a die. A rapid viscoanalyser (RVA) was used for the pasting study; the parameters determined were the initial viscosity (IV), peak viscosity (PV), hot‐paste viscosity (HPV) and cold‐paste viscosity (CPV). The PV, HPV and CPV generally decreased with increasing barrel temperature and screw speed. The IV was high, 30–43 rapid viscoanalyser units (RVU), for extrudates compared with raw rice, 3–4 RVU. The extent of gelatinization (GE) of the extruded rice samples ranged between 93.8% and 99.0%, and an increase in screw speed enhanced the GE values. Regression equations ( r > 0.991, P < 0.01) that relate pasting and gelatinization behaviour to temperature and screw speeds are reported.