starches can withstand the acidities typical of yogurt and many fruits (pH 4) Gentle and brief cooking will minimize acid breakdown Proteins and Fats Two other materials are commonly found in sauces and have some influence on their texture Flour is about 10% protein by weight, and much of this fraction is insoluble gluten Gluten aggregations probably get caught in the starch network and so slightly increase the viscosity of the solution, though the pure starches are generally more powerful thickeners overall Sauces based on concentrated meat stocks also contain a good deal of gelatin, but gelatin and starch seem not to affect each other’s behavior Finally, fats are usually present in the form of butter, oil, or the drippings from a roast They do not mix with water or water-soluble compounds, but they do slow the penetration of water into starch granules Fat does contribute the sensations of smoothness and moistness to a sauce, and when used to precook the flour in a roux, it coats the flour particles, prevents them from clumping together in the water, and so safeguards against lumps Incorporating Starch into Sauces In order to thicken a sauce with starch, the cook must get the starch into the sauce Very basic, but not so simple! If you add flour or starch directly to a hot sauce, it lumps up and never disperses evenly: the moment they hit the hot liquid, the clumps of starch granules develop a partly gelated, sticky surface that seals the dry granules inside and prevents them from dispersing Slurries, Beurre Manié, Floured Meat Cooks use four methods for incorporating ...contribute the sensations of smoothness and moistness to a sauce, and when used to precook the flour in a roux, it coats the flour particles, prevents them from clumping together in the water, and so safeguards... starch directly to a hot sauce, it lumps up and never disperses evenly: the moment they hit the hot liquid, the clumps of starch granules develop a partly gelated, sticky surface that seals the dry granules inside and prevents them from dispersing... particles, prevents them from clumping together in the water, and so safeguards against lumps Incorporating Starch into Sauces In order to thicken a sauce with starch, the cook must get the starch into the sauce Very basic, but not so simple! If you add flour or