1Department of Food Science and Technology, Punjab Agricultural University, Ludhiana -141 004, Punjab (India)
Division of Post Harvest Technology, S.K. University of Agricultural Sciences and Technology of Kashmir, Shalimar, Srinagar -190 025, Jammu & Kashmir (India)
*Email: zameerskuastj@rediffmail.com; szhussain4u@gmail.com
Online published on 9 December, 2014.
The effect of feed moisture, screw speed and barrel temperature on colour coordinates of re-fabricated rice grains were investigated in a co-rotating twin-screw extruder using response surface methodology. The rice flour obtained from broken rice (< 1/8th was used in the study. The screw speed was set at five levels between 49 and 150 rpm, barrel temperature between 59 and 110°C and feed moisture between 31 and 45%. All colour coordinates of re-fabricated grains evaluated (total colour difference) and hue angle were significantly affected by the three process variables. Barrel temperature was the most significant variable with quadratic effect on a*. Response surface regression models were established to correlate the colour coordinates of refabricated rice grains to the process variables. The optimized extrusion conditions for preparation of re-fabricated grains were 38%, moisture content, 130 rpm screw speed and 89°C barrel temperature. A significant change was observed in maillard precursors i.e. sucrose, glucose, fructose and maltose levels of re-fabricated rice obtained at optimum extrusion
Barrel temperature, colour coordinates, extrusion, refabricated rice, response surface methodology, screw speed
