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Complex Carbs. Ch 9 Day B. Functions of complex carbohydrates. Structure- in baked goods and other products Cellulose forms the framework for fruits and veggies Pectins and gums provide texture for jelly and gummy candies, ice cream etc. Starch.

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complex carbs

Complex Carbs

Ch 9 Day B

functions of complex carbohydrates
Functions of complex carbohydrates
  • Structure- in baked goods and other products
    • Cellulose forms the framework for fruits and veggies
    • Pectins and gums provide texture for jelly and gummy candies, ice cream etc
starch
Starch
  • Polymers of glucose (>500 glucose molecules)
  • Linked by alpha-1-4
  • Digestible
starch1
Starch
  • Present in plant materials as “starch granules”
    • Starch molecules in the form of densely packed bundles
    • Visible in sliced potato with food color

Linear

Alpha 1,6

Branched

amylose
Amylose
  • Molecules contribute to gel formation:
    • Linear chains
    • Orientation parallel to each other
    • Moving close enough together to bond ( hydrogen bonds)
amylopectin
Amylopectin
  • Branched molecules give viscosity to cooked paste
  • Side chains /bulky shape
  • Keep them from bonding together
    • Not contribute to gel formation
  • Doesn’t get as organized as amylose,
  • It thickens but does not gel
  • (Tumbleweed analogy)
starch granules
Starch granules

Contain both linear amylose and branched amylopectin

Eg) corn starch, 1,3 amylose: amylopectin

( ratio depends on type of starch)

starch2
Starch
  • soluble in cold water…..but
  • Gelatinization
    • Heat + water
    • Starch granules swell and eventually burst
      • Starch molecules absorb water
      • Examples:
      • Raw vs cooked
        • Potato, rice, pasta
gelatinization
Gelatinization
  • Raw STARCH

Heat and Water

When starch is heated in water the bonds joining amylose and amylopectin are weakened

That allows water molecules to move in and form “H” bonds

( water pushes the Hydrogen bonds apart)

slide10

Starch = alpha -1,4,1-6= digestible

  • Cellulose = beta-1,4= indigestible
    • Cows can digest this….people cannot
  • Both are linear chains of glucose units
functions of complex carbohydrates polysacchr
Functions of complex carbohydrates (polysacchr)
  • Bind, Stabilize
    • Hold batters to foods when deep fried
    • Carageenan- stabilizes cocoa in chocolate milk
    • Guar and xanthan gums improve consistency of gluten free baked goods
    • Keep compounds, mixtures and solutions from changing state
  • Fat replacers
    • Regular vs light mayo
functions of complex carbohydrates1
Functions of complex carbohydrates
  • Thicken- Starch
    • Starch must be heated to allow starch to swell and take up water
    • Heating breaks intermolecular bonds exposing polar structures that attract water.
    • Gelatinization- thickening a liquid with starch
    • Gelatinization point- temperature of maximum swelling
      • Holds the most water
      • Has greatest thickening power
    • Too much heat will break down (hydrolyze) the starch
      • Too high heat
      • Heating too long
    • Salt and sugar will interfere with gelling
        • Sugar decreases strength and viscosity
        • Salt has different effects on different starches
functions of complex carbohydrates2
Functions of complex carbohydrates
  • Pectins
    • Used to thicken jams and jellies
    • Found in skins of fruits and vegetables
    • Sold as powder or liquid
thickened starch mixtures
Thickened Starch Mixtures

Types

• Sol—a thickened liquid

• Paste—thickened starch mixture that has little flow but is

spreadable

• Gel—a rigid starch mixture

Properties

• Retrogradation—gel becomes firm as it cools (Lemon pie)

• Syneresis—water leaks out of gel during storage

• Viscosity—resistance to flow

• Gelatinization—starch granules absorb water and swell,

causing thickening of liquids

retrogradation
Retrogradation
  • After gelatinization= upon cooling and storage
  • Linear amylose- chains orient back to crystalline zones ( intermolecular H-bonding)
  • Syneresis (loss) of water
  • Toughening food, gritty texture
  • eg stale bread, gritty starch pudding
  • Can be partially reversed by heating
    • Especially mashed potatoes
    • Will not completely return like original due to starch molecule explosion
  • Better to store bread in freezer than refrigerator. Freezer locks in moisture
slide16

Stability- ability of a thickened mixture to remain constant over time and temperature changes.

  • Waxy maize starch is as thick when hot as it is cold
  • Corn starch has more thickening power than flour, but unstable with prolonged heat
  • Flour might be better choice for gravy not served right away
starch appearance
Starch appearance
  • Opacity- how much something blocks light
  • Translucency- how much light passes through something
  • Translucent: corn starch, potato starch, arrowroot
    • Good for fruit sauces
  • Wheat flour good for white foods.
starch texture
Starch texture
  • FDA does not require identification of sources of modified starches
    • wheat,corn, or soy ( corn most common in US)
    • Most modified by hydrolysis
  • Cross linked starch- designed to be more resistant to acids and separation in the freeze / thaw process
    • Used in baby foods, salad dressings , cream corn, fruit pie fillings
  • Modified starches- stabilize condiments, sauces and relishes
thickening sauces with starch avoiding lumps
Thickening Sauces with starchAvoiding lumps:
  • Cold water paste:
    • Slurry- uncooked liquid and starch
  • Starch and Fat
    • Roux- cooked fat and starch paste
    • Beurremanie- equal parts butter and flour
  • Starch and Sugar
    • Starch and sugar then add liquid
    • Used in sweet sauces and puddings
nutrition of complex carbs
Nutrition of Complex Carbs

= digestible starches and indigestible fiber

4 cal/g beta glucose= fiber

Most abundant/ economical most abundant

Should provide ½ + daily cal feel full, aids elimination

Glucose is only energy brain can use lowers risk of colon cancer

Excess CHO stored as glycogen plant cell wall material

Body uses stores w/in 2hrs heavy exercise linear glucose chains

Skipping meals slows brain and organ stores

If no carbs… body goes into ketosis

Ketosis- elevated ketones damages kidney

nutritional functions of cho
Nutritional Functions of CHO
  • Provide energy
  • Bulk for digestion
  • Tie up bile acids( decreasing reabsorption)
  • Lowers cholesterol levels in the blood
  • Promotes utilization of fat
  • Half of carbs should be whole grain sources