Influence of various cereal flours on physical properties of expanded extrudates (Thai)

Abstract

The process variables for expanded extrudates using the extrusion process comprise raw materials and process conditions. A study of raw materials, such as wheat flour (A), corn flour (B) and rice flour (C) on the physical properties of products was performed. Three kinds of flour were mixed in a ratio ranging from 0 to 1. The process conditions were temperature (D) from 150 to 180 o C and raw material moisture (E) from 14 to 19% which affect the physical properties of products such as expansion ratio, bulk density, maximum force, water absorption index, and percent water solubility. Physical properties were evaluated using some quality aspects including expansion ratio, bulk density, maximum force, water absorption index, percent water solubility. A single screw extruder was used to extrude the raw materials. D-optimal design was used to relate the process variables to physical properties of products. It was found that the relationship between these variables could be fitted by a mathematical model using polynomial regression. The mathematical model could be used to predict the physical properties of products. The optimum conditions of the process from the mixtures of wheat, corn and rice flour both individually or in a mixture of the flours in various ratios was 16.5% moisture content and barrel temperature of 165 o C which provided high expansion products.