Modification can also transform starch into an emulsifier. “Lipophilic starches are modified by the addition of lipophilic substituents (octenly succinate anhydride, OS),” says Wicklund. “OS starches contain lipophilic and hydrophilic regions that give them great emulsifying and stabilizing properties. Since the starch thickens and stabilizes the aqueous phase while also emulsifying the oil phase, the total amount of starch and other thickeners is reduced, which can help save on cost.” Lipophilic starches can also replace egg yolk to address economic, allergenic and logistical concerns. Replacement of other emulsifiers, such as polysorbate 60, can simplify and increase appeal of the ingredient statement.
Hydrolysis of starch yields maltodextrins, which “are used in both pourable and spoonable dressings to build solids and lubricity when fat levels are reduced,” says Sullivan. “They provide mouthfeel and body, and have very clean flavor profiles that do not mask other flavors.”
Maltodextrins’ functionality is dictated by the extent to which the original starch is processed. “Dextrose equivalence (DE) is a quantitative measure of the degree of starch polymer hydrolysis. As the product is further hydrolyzed—higher DE—the average molecular weight decreases and the carbohydrate profile changes,” Sullivan says. “A low-DE maltodextrin contributes to a smooth, creamy mouthfeel and exhibits fat-like lubricity in reduced-oil applications.”
Jumping the gum
Three food gums have dominated the dressing industry: xanthan, propylene glycol alginate (PGA) and guar.
Xanthan gum provides cold-soluble viscosity and emulsion stability that is virtually unaffected by heat, pH, salt and enzymes. Xanthan also imparts shear-thinning behavior: It’s pourable after applying shear (shaking), then returning to peak viscosity when shear is ceased (at rest on salad).