To make hot-process spoonable salad dressings, starch, vinegar, salt, sugar, and water are cooked to make a paste. After the paste is cooled, the remaining ingredients are added, including the oil, which is typically mixed with egg yolks, whites, or another emulsifier. To make the emulsion even finer and more stable, the entire mixture is sent through a colloid mill, which is a high shear process.
Cold-process dressings follow a similar flow, but without heating. Pourable dressings are more often made via a cold process.
Starch is added to dressings to thicken and stabilize them and to make them easier to cut and pour. However, when used in cooked dressings, the starch must be highly crosslinked because of the low pH, high temperatures, and high shear involved. The level of monosubstitution depends on the desired texture and formulation.
Spoonable dressings with higher fat content often use a blend of modified waxy maize and dent corn starches. The modified dent corn starch is added to provide a shorter texture and enhance cuttability. Additional cuttability can be provided by adding unmodified dent corn starch. Pourable dressings, on the other hand, typically only use modified waxy maize starch.
Potato and tapioca starches don’t work well in dressings because they’re more likely to break down due to acid and shear. Dressings with less fat typically use a more stabilized waxy maize starch. Fat-free dressings use fat replacers such as dextrins, maltodextrins, or hydrolysates.
To get the desired texture in nonstandardized products like pizza sauces, texturizer starches are added. These starches are highly cross-linked and drum dried. Hydrophobic starches with modified protein are used in sterilizable dressing emulsions and canned fish products.