Effects of Xanthan Gum Addition and Extrusion Parameters on Properties of Starch-Based Fried Corn Extrudates

Abstract

Starch-based corn grits are extruded and then the extrudates are fried to development for corn snacks with low oil content, improved texture, and preserved color characteristics. Effects of screw speed (100-300 rpm), feed moisture (37-47%), and xanthan gum (XG) level (0-1%) on expansion, oil absorption, hardness, color, and microstructural properties of fried extrudates are examined. Increased screw speed increases expansion index (EI) due to enhanced starch gelatinization. Elevated feed moisture content increases EI as a result of the low solubility index of starch-based extrudates. The oil absorption of extrudates increases as screw speed and moisture content are elevated as a result of holes in the surface after frying. On the other hand, the incorporation of XG decreases oil absorption due to reduced holes on the surface. Hardness values range from 7.58 +/- 0.47 to 42.26 +/- 1.44 N. Increasing moisture content decreases the hardness of fried extrudates while increasing screw speed results inan increase in hardness. The incorporation of XG increases the hardness of extrudates. Increased screw speed, feed moisture, and XG ratio increase the lightness value and decrease the redness value. Browning index (BI) is decreased with an increase in feed moisture and XG level.