Optimization of Process Variables for Extrusion of Rice – Bengal Gram Blends

Abstract

<span style="font-size:11.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">Extrusion-cooking is advantageous for vulnerable foods and offers a chance to use raw materials which have not previously displayed great economic importance or have even been regarded as waste. Rice and pulse milling by-products due to the low price and easy conversion to processed products result in increasing demand for conversion of these by-products into useful products. It delivers good profit for the processors and in turn providing the consumer a healthy pulse based product to choose from, which is now lacking in the market. This study focuses on optimizing the process variables and to study the extrudate characteristics from blends of bengal gram and rice using single screw extruder. Central composite rotatable design was used to design the experiment with the die head temperature (150-190°C), screw speed (80-100 rpm) and bengal gram level (5-25%) as independent variables. The effect of the variables on the product responses (bulk density, water absorption index, water solubility index, expansion ratio, colour) was carried out. The changes in die head temperature and bengal gram composition were found to have significant effect to the product responses while compared to change in screw speed which is found to have a lesser significant effect to the product response.</span>