EFFECT OF EXTRUSION PARAMETERS ON PHYSICAL PROPERTIES OF TUR DAL (PIGEON PEA) ANALOGUES DEVELOPED FROM TUR DAL BROKENS

Abstract

Dehusking and splitting are typically the steps involved in converting pulses into dal. The milling losses in commercial pulse mills can be attributed to the small brokens and fine powders found during scoring and concurrent dehusking and splitting operations. The fracture of dal kernels during the milling process is a problem in the dal milling industry, and customers don’t generally like these broken kernels. The only way to turn these unused milling fractions into profitable products is through extrusion cooking. Extrusion cooking of flour of redgram dal brokens with addition of some additives was done to prepare Tur dal analogues at various extrusion process parameters. The effect of barrel temperature (120 – 175 oC), feed moisture content (18-25%), feed rate (40-60 kg/h) and screw speed (100-220 rpm) on bulk density, expansion ratio and hardness of Tur dal analogues were investigated. To develop the prediction model, a central composite rotable design (CCRD) using response surface method (RSM) was applied. Each variable’s impact on the responses was measured via regression equations. The second-order quadratic regression model fit the variation adequately. The significance was established at p0.05. An increase in bulk density and decrease in expansion ratio with increase in feed moisture content and feed rate was observed. The bulk density and hardness increased as the barrel temperature increased when the feed moisture content was lower; conversely, when the feed moisture content was higher, the bulk density and hardness reduced as the barrel temperature increases.