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STARCHES AND SAUCES Chapter 17

STARCHES AND SAUCES Chapter 17. Starch manufacture. Involves freeing starch granules from the other constituents by Screening Washing Utilization of centrifugal separators Drying. Starches Mainstay of many diets: potatoes, beans, rice Complex CHO Yields Energy

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STARCHES AND SAUCES Chapter 17

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  1. STARCHES AND SAUCESChapter 17

  2. Starch manufacture • Involves freeing starch granules from the other constituents by • Screening • Washing • Utilization of centrifugal separators • Drying

  3. Starches Mainstay of many diets: potatoes, beans, rice Complex CHO Yields Energy 55-66% Total Kcal from CHO 4 kCal Per Gram Uses Thickeners Stabilizers Texturizers Water or Fat Binders Fat Substitutes Emulsification Aids STARCHES

  4. Starch in food products • Thickening/gelling agent: soups, sauces, pie fillings, gravies,chili, stews, cream fillings, whipped topings, pudings, candies, salad dressings etc • Edible films: protective coating for chewing gums, to bind food together (meat products, pet foods), act as a base to hold flavor oils • Starch syrups • Dextrose (glucose): sweetener

  5. Provide Texture Taste Appearance Sauces Gravies Cream soups Chinese dishes Salad dressings Desserts Cream pies Fruit pies Puddings Tapioca Rely on thickening agents for quality STARCHES

  6. STARCHES Sources of Starch • Word Starch derived from German for Stiff • Thickening or Gelling Agent • Plants Yield Starch Granules • Granules Differ In Shape & Size • Cornstarch Major Source – 95% - US

  7. Starches • USA, Canada - corn starch • Sweden, Poland, Germany, Holland, France – potato starch • Europe – wheat starch • Brazil, East Indies-tapioca starch • Africa, Caribbean –arrowroot starch

  8. Starch granules • Insoluble in water • Polygonal, oval or round shape • Shape and size are fingerprints for starch origin • Potato starch granules the largest of any commercial starches

  9. STARCHES

  10. Cereal Starch Wheat Rice Root Starch Potato Arrowroot Cassava Tapioca Complex CHO Dried Beans Peas Sago Palm Starches vary by Flavor Viscosity STARCHES

  11. STARCHES Starch in Food Products • Thickening Agent • Edible Films • Dextrose • Starch Syrups

  12. STARCHES

  13. Chemical structure of starch • Polymeric carbohydrate (homopolysaccharide) made of glucose. • Two major types of polysaccharides are present in starch granules: amylose and amylopectin.

  14. STARCHES

  15. Amylose • Linear polysaccharide made of glucose linked through a (1→4) glycosidic bond. • May contain 200-2000 glucose units. • Starch granules contain 18-28% of amylose (cereal starches are at the higher end). • Amylose can be separated from amylopectin by selective precipitation (forms insoluble complexes with butanol and other organic substances with hydrophilic groups). • In water solution amylose molecules have tendency to orient themselves in parallel fashion. In diluted solution this leads to starch precipitation, while in concentrated solution due to steric hindrance this leads to formation of gel. (retrogradation). • Amyloses have affinity for iodine, fatty acids, long chain alcohols and formed helical complex around such molecules.

  16. Amylopectin • Branched polysaccharide made of glucose linked through a (1→4) and periodic branches at carbon 6. • Each branch may contain 20-30 glucose units. • Large size and presence of branches reduces the mobility of amylopectin molecule and interfere with any tendency to form sufficient amount of hydrogen bonds. • Amylopectins are resistant to gelling.

  17. In starch granules • Amylopectin and amylose fraction are oriented in a radial fashion • Wherever linear segments of these molecules run closely parallel, hydrogen bonding occurs and micellar crystallites are formed. • This imparts birefringent properties manifested by polarization crosses when granules are examined microscopically between crossed Nicol prisms.

  18. STARCHESCHARACTERISTICS Starches Undergo • Gelatinization Heated in Liquid Starch Granules ↑ in • Volume • Viscosity • Translucency • Gel Formation • Retrogradation • Dextrinization

  19. Gelatinization • Swelling of starch granules leads to an increase of viscosity during heating in water. This swelling change the texture of food products such as puddings, sauces soups.

  20. Gelatinization Dependent on Amount of Water Temperature Timing Stirring Presence of Acid Sugar Fat Protein STARCHESCHARACTERISTICS

  21. STARCHES

  22. STARCHESCHARACTERISTICS Gel Formation • Sol • Fluid Starch Paste • Gel • Semisolid Paste • Forms after Cooling < 100º • Requires Sufficient Amylose

  23. STARCHESCHARACTERISTICS Gel Formation cont. • Amylose Cornstarch • ↑ Amylose Opaque Gel Potato, Tapioca • ↓ Amylose Clearer Gel Waxy Hybrids - Corn & Sorghum Cross • ↓↓ Amylose Do Not Gel

  24. STARCHESCHARACTERISTICS Retrogradation Gel Cools Seepage of H2O Out of Aging Gel Syneresis or Weeping Contraction of the Gel Amylose Molecules Tighten Bonds Accelerated by Freezing Prevention Use Foods Immediately

  25. STARCHESCHARACTERISTICS Dextrinization Breakdown of Starch Molecules Presence of Dry Heat Smaller Sweeter-Tasting Dextrin Molecules Thickening Power Diminished Louisiana Gumbo Dark Flour

  26. STARCHES

  27. Starches • Waxy starches • High amylose starches (up to 70%)

  28. Native Starches- Problems • The lack of free flowing properties or water repellency of starch granules • insolubility or failure of granules to swell and develop viscosity in cold water • excess or uncontrolled viscosity upon cooking • cohesive or rubbery texture of cooked starches • the sensitivity of cooked starches to breakdown during extended cooking when expose to shear or low pH • the lack of clarity and the tendency of starch sols to become opaque.

  29. Modified Gelatinization Heating Times Freezing Stability Cold H2O Solubility Viscosity Three Types Cross-Linked Starch Oxidized Starch Instant or Pregelatinized Starch STARCHESCHARACTERISTICS

  30. STARCHESCHARACTERISTICS Cross-Linked • Chemically Treated Link Starch Molecules w/ Crossbridges • Cross-Linking Starch More Heat Resistant

  31. STARCHES Modified Starch • Starch Chemically or Physically Modified to Create Unique Functional Characteristics

  32. SAUCES Functions • Moistness • Flavor • Texture • Body esp. to Soups • Appearance - Rich Color & Shine • Fish Meats Vegetables More Appetizing & Appealing w/ a sauce

  33. Types Thickened Cheese Sauce White Sauce Some Gravies Table 17-3 Unthickened Other Gravies Hollandaise Butter Fruit Barbecue Tartar Tomato Sauces SAUCES

  34. SAUCES

  35. Types Mother Sauces Grand Leading Major Béchamel White Espagnole Brown Hollandaise Tomato Velouté Small Sauces Secondary Sauce Mother Sauce Base Examples Cheese Curry Mushroom Shrimp SAUCES

  36. SAUCES

  37. SAUCES Ingredients • Smooth Texture Starch Gelatinization Liquid • White or Brown Stock • Milk Clarified Butter Tomato Juice Thickening Agent • Starch Seasonings/Flavorings • Salt Black, White, or Cayenne Pepper Lemon Juice Herbs Wine

  38. Glaze Flavoring from Soup Stock Concentrated by Evaporation to a Syrupy Consistency w/ Highly Concentrated Flavor Glazes Less Shelf Space Last Months when Refrigerated Convenient SAUCES

  39. Roux Foundation of Thickened Sauces Equal Parts Fat & Flour Three Types White Blond Brown Variations in Heating Times of Fat-Flour Combination Cause Differences in Colors & Flavors SAUCES

  40. SAUCES Beurre Manié - burr mahn-YAY • Soft Paste Equal Parts Soft Butter & Flour Blended Together

  41. SAUCES Slurry • Combine Starch & Cool Liquid Cool Liquid Inhibits Granule Expansion • Mix Into Simmering Liquid Base Heat Causes Granule Expansion • Sauce Thickens • May Yield Starchy Taste • Less Stable Thickening

  42. SAUCES Roux Required for White Sauce • Butter Flour Milk Seasonings

  43. SAUCES Sauce from Roux • Melt Fat • Mix in Flour • Heat until Desired Doneness White Blonde Brown • Combine Liquid & Roux Gradually Add Liquid while Whisking

  44. SAUCES Sauce from Rouxcont. • Heating the Sauce • Adding Seasonings/Flavorings • Cheese Sauce Table 17-6 • Preventing Lumps Blend Fat & Flour until Smooth Add Small Amount of Sugar Vigorously Mix ~ 2 T Starch w/ Cold Water

  45. SAUCES No Starch or Thickening Agent • Gravy Juices or Drippings Remaining in Pan After Meat or Poultry is Cooked Drippings Served Thickened & w/ Added Seasonings or Unthickened • Au Jus Served w/ its Own Natural Juices Reference to Roasts

  46. SAUCES Unthickened • Gravy Step 1 Degreasing Step 2 Deglazing Step 3 Reduction Step 4 Straining Step 5 Seasoning

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