WHAT IS STARCH? Starch is a complex carbohydrate

stored in plants Cereal grains contain plant cells that

are source of starch

Common starches used in cooking: wheat flour cornstarch tapioca

How is starch used? Starch is primarily used as a thickening

agent Mixtures thickened with tapioca and

cornstarch are translucent (light passes through, but not clear)

Mixtures thickened with flour are opaque (cannot see through)

FOOD SCIENCE AND STARCH Sauces usually must be thickened Most thickening agents are forms of

starch Starch granules will absorb moisture

when placed in a liquid That process is called gelatinization

Characteristics of Sauces No lumps Flavor that is not starchy or pasty Sticks to the back of a spoon Will not break apart when cooked

MOIST HEAT Mixing starch with water and heating

them causes the starch to become soluble

Starch granules absorb water and swell or get bigger

The swelling causes the mixture to thicken

As starch mixture becomes thicker it reaches maximum thickness known as gelatinization

COOLING PROCESS During cooling, bonds form between

the starch molecules The starch mixture forms gels which

hold water If your product stands too long, the gel

breaks and water may leak out. This is called syneresis

What food products are thickened with starch? Gravy Cooked Pudding Pie Filling Sauces – sweet and savory

Thick Chocolate Sauce1 T. cornstarch 1 C. boiling

water¼ cup cocoa ½ tsp. vanilla½ cup sugar 1/8 tsp. saltMix dry ingredientsAdd water to dry mix slowlyBoil slowly about 5 minutes, stirring

constantly. Do Not Scorch (burn)Add vanilla and serve.