Flow Behavior of Low Fat Salad Dressing Thickened by Rice Flour–Xanthan Gum Combinations

Abstract

This research studied the flow behavior of low fat salad dressing thickened by rice starch–xanthan gum combination using central composite design (CCD) of three factors. The three independent variables investigated in this experiment were 16.84-25.2% soybean oil (x₁), 0.9-5.1% rice flour (x₂) and 0.09-0.5% xanthan gum (x₃) by weight. Dependent variables of Herschel-Bulkley equation were yield stress (y₁), consistency coefficient (K) (y₂) and flow behavior index (n) (y₃). The results found that the yield stress increased with increasing soybean oil and xanthan gum.  The consistency coefficient increased with increasing rice flour and xanthan gum. In addition, the highest flow behavior index (n = 0.64) was obtained from the contour plot when using rice flour 2.65% and xanthan gum 0.28%. The 3 low fat salad dressings that had the flow behavior similar to that of commercial low fat salad dressing were selected for sensory evaluation using 9-point hedonic scale. It was found that the ratio of soybean oil: rice flour: xanthan gum equaled to 24.04 : 4.5 : 0.45 by weight gave the highest score of texture, consistency, color, taste, flavor and overall liking.