Physical properties of dressing-type oil in water emulsions as affected by okra gum-xanthan gum-corn starch interactions

Abstract

Okra gum is one of potential hydrocolloids due to its’ suspending and emulsifying abilities and blending it with other gums shall widen its application in emulsion-based food products. Therefore, interaction effects of okra gum (OG), xanthan gum (XG) and corn starch (CS) on the physical properties of dressing-type emulsions were investigated in this study using a simplex-centroid mixture design. Application of OG:CS blend resulted in smaller droplet size range (5.40 – 11.22 μm) compared to XG:CS (4.82 – 13.97 μm) with the same gum ratio (i.e. 1:1), due to emulsifying property of OG. Emulsion prepared with this blend also exhibited better viscosity (30.43 ± 9.81 Pa.s) and turbidity (Absorbance value = 0.95 ± 0.12) compared to other emulsions with individual OG or CS. Regression modelling further confirmed the occurrence of synergistic interaction in OG:CS blend which positively affected these emulsion properties. Droplet size and turbidity responses were successfully fitted with a special cubic model while viscosity response was successfully fitted with quadratic model (no lackof- fit, p > 0.05). The models are useful for predicting the respective responses to any blend combination of the components. Results of this study signify that OG is a promising hydrocolloid showing synergism with CS and this synergism can be manipulated to overcome lack of OG performance in food emulsion.