CHAPTER 20

STARCHES AND SAUCES

  1. STARCHES AS THICKENERS
  1. Sources of Starch
  1. Background
  1. derived from Germanic root word meaning stiff
  2. plant sourced
  3. granules differ in size and shape depending upon origin
  1. Cereals
  1. wheat
  2. rice
  3. corn
  1. most commonly used in U.S.
  2. kernels are cracked after soaking and ground & screened to yield starch and protein
  3. the protein is removed and the starch is filtered, washed, and dried then packaged as cornstarch
  1. Roots
  1. Potatoes (largest)
  2. arrowroot
  3. cassava
  1. Food Products
  1. Thickening agents
  1. used as a thickening / gelling agent
  2. soups, sauces, pie fillings, pudding, salad dressings
  1. Edible films
  1. holds flavors and oils next to food products
  2. chewing gum and pet food
  1. Dextrose
  2. Starch syrups
  1. corn syrup
  2. used in beverages, jellies, desserts
  1. Starch Structure
  1. Polysaccharide consisting of long chains of repeating glucose molecules
  2. Most starches contain 75% amylopectin (branch chain structure) and 25% amylose (straight chain structure)
  1. STARCH CHARACTERISTICS
  1. Gelatinization
  1. Occurs when starch granules are heated in a liquid
  2. Heat weakens the bonds and allows water to penetrate starch causing it to swell
  3. Factors influencing gelatinization
  1. water
  1. amount available
  2. concentration of amylose and amylopectin in the starch
  1. temperature
  1. 133 degrees to 167 degrees F
  2. larger starch granules gelatinize at lower temperatures
  3. smaller starch granules at higher temperatures
  1. timing
  1. starch granules begin to break when heated too long
  1. stirring
  1. initially, stirring is done to have uniform consistency
  2. continued stirring will cause the starch granules to break
  1. acid
  1. a pH below 4.0 weakens the starches structure
  1. sugar
  1. competes with starch for water
  2. delays the onset of gelatinization
  3. requires an increased temperature
  4. excessive amounts of sugar will inhibit complete gelatinization and result in a runny paste
  5. most powerful sugars

-sucrose

-lactose

-glucose

-fructose

  1. fat / protein
  2. will coat the starch and prevent absorption of water
  1. Gel Formation
  1. Gel formation occurs after gelatinization
  2. Definitions
  1. sol – fluid starch paste
  2. gel – semi-solid starch paste
  1. Not all starches will gel, but those that will gel below 100 degrees F
  2. Gel formation is dependent upon a sufficiency of amylose molecules
  1. amylose will gel due to linear structure and creates a three-dimensional structure trapping water
  2. amylopectin will not due to branched structure
  1. Retrogradation
  1. Def – seepage of water out of an aging gel due to contraction of the gel
  2. Using the gelled food as soon as possible is the best prevention
  1. Dextrinization
  1. Def – breakdown of starch molecules to smaller, sweeter-tasting dextrin molecules in the presence of dry heat
  2. Toasting / baking
  1. Modified starches
  1. Def – a starch that has been modified to create unique functional characteristics
  2. Cross-linked starches
  1. makes a starch more heat resistant and is less likely to lose viscosity when exposed to heat
  2. barbecue sauces, pie fillings, cheese, pudding
  1. Oxidized starches
  1. less viscous than cross-linked
  2. clearer in appearance
  3. ideal for dusting foods

i.chewing gum

  1. marshmallows
  1. instant (pregelatinized)

i.do not need heat treatment

ii.already cooked and dried

  1. dry puddings, gravies, sauces
  1. SAUCES
  1. Thickened Sauces
  1. Basics of thickened sauces
  1. liquid

i.stock

-chicken

-veal

-fish

ii.brown stock

  1. milk
  2. clarified butter
  3. tomato juice
  1. thickening agent

i.wheat flour

  1. cornstarch
  2. arrowroot
  1. seasonings / flavorings

i.salt / pepper

ii.acid

-vinegar

-wine

-lemon juice

  1. Thickeners and sauce preparation
  1. first step is to add thickener

i.roux (cooked)

-flour

-butter

ii.beurre manie

-uncooked

-whisked in during cooking until desired

consistency

-used in small amounts

  1. slurry

-cold liquid added to dry starch

-less stable than roux thickened sauces

  1. add the liquid (usually hot)
  1. Lump prevention
  1. roux should be blended until smooth before adding any liquid (starch is coated by fat)
  2. add a small amount of sugar to starch (separates granules)
  3. mix a small amount of starch vigorously with cold water and then add to liquid to be thickened before adding roux
  1. Unthickened Sauces
  1. Gravy
  1. au jus
  2. pan gravy

i.liquids and residues on bottom of pan must be separated from fat

-refrigerate

-skim

  1. deglazing – loosens particles stuck to bottom of the pan
  2. reduction – concentrates flavors
  3. seasoning
  4. service
  1. Hollandaise sauce
  1. egg yolks
  2. butter
  3. acid
  1. Barbecue sauce
  2. Butter sauce
  3. Fruit sauce
  4. Tartar sauce
  5. Tomato sauce
  1. STORAGE OF STARCHES AND THICKENED SAUCES
  1. Dry starch should be stored in an air-tight container away from heat
  2. Thickened sauces should be refrigerated