NS415 Food Science with Lab Seminar 2 – Starch & Grain Components Brook Benton, MS, RD, LDN, CDE Nanna Cross, PhD, RD, LDN

Review of Lab 1

Questions regarding Unit 2 lab reports? A. Starch principles Pages 23-24 in Laboratory Manual Follow instructions for the type and amount of starch in Table 3.1, page 24. Do ONLY treatment numbers 1, 3, 5, 7 & 8 and describe firmness and appearance in the table. Answer questions 1-5, page 24 B. Effect of water temperature on starch dispersion Page 25; answer questions, page 25

What are the most common sources of food starch?

Starch Storage form of carbohydrate Common sources Seeds, roots, tubers Cereal grains – corn, wheat, rice, oats Legumes Roots and tubers – potato, tapioca, arrowroot

Starch Less common sources of starch Check out Web Resources within the course www.quinoa.net www.grains.org www.ilovepasta.org www.riceland.com

Starch Molecule Starch is a polysaccharide. Polysaccharide is made up of hundreds or thousands of glucose molecules. Polysaccharide – a complex carbohydrate. Glucose – a monosaccharide or simple sugar.

There are two kinds of starch molecules There are two kinds of starch molecules. What are the two kinds of starch and how do they differ in structure?

Two Kinds of Starch Molecules Amylose Long chainlike Corn starch and wheat flour Amylopectin Branched, bushy structure Tapioca has the highest amount of amylopectin Most starches are a mixture of the two of these in varying degrees

Two Kinds of Starch Molecules Amylose Provides gelling characteristic For example, pudding or cream pie Amylopectin Provides cohesion or thickening properties when cooked with liquid For example, gravy or thickening for fruit pies

Cooking with Starches

What factors are required for gelatinization & gel formation of starch?

Changes in Starch with Cooking Moisture – dissolves starch Heat – starch granules swell Cooling - retrogradation

Preventing Lumping in Powdery Starches Before hot liquids are combined with starch, the particles of starch must be separated to bring about a uniform dispersion of well hydrated starch granules This process can be accomplished in one of three ways before adding hot liquid: Dispersing the dry starch with melted fat Blending the dry starch with sugar Mixing the dry starch with cold water to form a slurry

Characteristics of Native Starches Cornstarch Tapioca Wheat flour Potato Sweet rice Arrowroot *Table 13-2. page 219, Introductory Foods. Clear glossy sauce Tolerates freezing/thawing Opaque sauce Doesn’t tolerate heat Clear glossy sauce; tolerates high heat and acid

Starch Hydrolysis

Starch Hydrolysis Breakdown of starch molecule produces glucose Amylase Enzyme that hydrolyzes starch Acid May be a catalyst in reaction

Factors that alter gelatinization and gelation How do each of these factors influence gelatinization or gel formation of starches? Heat? Agitation? Other ingredients? Acid? 2. Sugar?

QUESTIONS???

What are the most important cereal grains used for food?

Cereal Grains Cereal grains are seeds of the grass family. Most important cereals used for food: Wheat, corn (maize), rice, oats, rye, barley, millet Cereal refers to a large group of foods made from grains: Flours, meals, breads, alimentary pastes or pasta

Structure of Whole Grains Outer bran - high in fiber Germ - rich in fat and protein Starchy endosperm - milled white flour comes entirely from the endosperm

Nutritive Value of Cereal Products Varies depending on the part of the grain that is used and the method of processing. Enriched flour is white flour with specified B vitamins and iron added.

What are the main purposes of cooking cereals?

Cereal Cookery Main purpose: to improve palatability and digestibility Factors that affect time required to cook include: Size of cereal particle Amount of water used Presence of absence of bran Temperature Method of cooking used

What is the appropriate method for cooking the following cereals: -Granular cereals such as farina and cornmeal -Rolled oats -Rice -Macaroni or spaghetti

Cooking Methods Granular Cereals Rolled Oats Rice Pasta 4 to 5 cups of water to 1 cup of cereal Rolled Oats 2 to 2 ½ cups of water to 1 cup of cereal Rice Twice the volume in water Brown rice takes twice as look to cook as white rice Pasta 2 – 3 quarts of boiling water for each 8 ounces of pasta Increases to 2 – 2 ½ times its original volume after cooked

QUESTIONS???

Name That Starch or Grain Term! Let's Play a Game! Name That Starch or Grain Term!

Name That Starch or Grain Term! I am the building block of a starch – also known as a monosaccharide

Name That Starch or Grain Term! I am the starch that has the highest amount of amylopectin – I provide the most thickening properties

Name That Starch or Grain Term! I am the sum of changes that occur in the first stages of heating starch granules in a moist environment - this includes swelling of granules as water is absorbed and disruption of the organized granule structure

Name That Starch or Grain Term! I am the process which takes place on the cooling of the starch paste following gelatinization

Name That Starch or Grain Term! I am a mixture of fat & flour cooked together

Name That Starch or Grain Term! Grits are made from me

Name That Starch or Grain Term! I am a basic dish produced when a cereal grain is browned in a small amount of hot fat before cooking it in water

Name That Starch or Grain Term! I am produced by crossbreeding rye and wheat

Name That Starch or Grain Term! When a starch has been _________, instant cereals can be prepared very quickly, simply by adding hot water

The End!