Acid (if used sparingly) is one of the most effective emulsion stabilizers. It is principally for this reason, and not because of flavor, that you add lemon juice (or vinegar) to your sauce and mayonnaise. Think of lemon juice's tart taste as a delightful bonus. Other natural emulsifier-stabilizers include mustard, cayenne pepper, and onions, which explains why they are common ingredients in vinaigrette sauces.
At the expense of flavor and texture, commercial sauce manufacturers give their products hyperstability by throwing into their mixing vats such stabilizers as monogyceride and diglyceride. Many restaurant chefs also scuttle flavor and texture by indiscriminately adding gelatin or starches such as arrowroot.
** Asian Recipes