complex carbs n.
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Complex Carbs

Complex Carbs

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Complex Carbs

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  1. Complex Carbs Ch 9 Day B

  2. 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

  3. Starch • Polymers of glucose (>500 glucose molecules) • Linked by alpha-1-4 • Digestible

  4. 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

  5. Amylose • Molecules contribute to gel formation: • Linear chains • Orientation parallel to each other • Moving close enough together to bond ( hydrogen bonds)

  6. 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)

  7. Starch granules Contain both linear amylose and branched amylopectin Eg) corn starch, 1,3 amylose: amylopectin ( ratio depends on type of starch)

  8. 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

  9. 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)

  10. 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

  11. 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

  12. 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

  13. Functions of complex carbohydrates • Pectins • Used to thicken jams and jellies • Found in skins of fruits and vegetables • Sold as powder or liquid

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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

  19. 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

  20. 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

  21. 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