Development of reduced-fat mayonnaise using 4alphaGTase-modified rice starch and xanthan gum.

In this study a disproportionating enzyme, 4-alpha-glucanotransferase (4alphaGTase), was used to modify the structural properties of rice starch to produce a suitable fat substitute in reduced-fat (RF) mayonnaise. The mayonnaise fat was partially substituted with the 4alphaGTase-treated starch paste at levels up to 50% in combination with xanthan gum and the physical and rheological properties of the modified RF mayonnaise samples were investigated. All mayonnaises prepared in this study exhibited shear thinning behavior and yield stress. Viscoelastic properties of mayonnaise were characterized using dynamic oscillatory shear test and it was observed that mayonnaises exhibited weak gel-like properties. The magnitude of elastic and loss moduli was also affected by 4alphaGTase-treated starch concentration and presence of xanthan gum. In relation to microstructure, RF mayonnaise prepared with 3.8 or 5.6 wt% of 4alphaGTase-treated starch and xanthan gum showed smaller droplets. The use of 5.6 wt% of 4alphaGTase-treated starch and 0.1 wt% of xanthan gum produced a RF mayonnaise with similar rheological properties and appearances as FF mayonnaise with gum. This study demonstrated a high feasibility for using 4alphaGTase-treated rice starch as a viable fat replacer in mayonnaise.