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Carbohydrate
-Carbohydrate foods provide practical energy sources b/c of their availability, low cost, & storage capacity
-provide both quick & extended energy for the body
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Photosynthesis
To transform solar energy into carbs; the stored fuel form of plants
Sunlight = Energy
-Plants containing chlorophyll are able to manufacture carbohydrate by combining CO2 and water
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Saccharide
-Chemical name for a sugar molecule
Saccarideis used as a carbohydrate classname, the word comes from the Latin word meaning sugar
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Simple Carbohydrate
Sugars with a simple structure of one or two single sugar units
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Complex Carbohydrate
Large complex molecules of carbohydrates composed of many sugar units.
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Carbohydrates are composed of:
- [CHO]
- Carbon (C)
- Hydrogen (H)
- Oxygen (O)
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Monosaccharides
Building blocks for all carbs that require no furthur digestion.
Glucose: -basic single sugar in body metabolism. - - form of sugar circulating in the blood & primary fuel for cells
- Fructose: mainly found in fruits; sweetest of simple sugars. (ex: honey)
- Galactose: comes from the digestion of milk sugar or lactose
Ex: Corn Syrup
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Polysaccharides
- complex carbs composed of many single-sugar units.Starch: most significant polysaccharide in the diet. Found in grains, legumes, & other veggies. Breaks down more slowly & supply energy over a long period
- Whole grain – Food products such as flour, bread,and cereals that still retain its outer bran layer andthe inner germ endosperm and nutrients (see page 19)
- Glycogen: Carb formed within the body's tissues & crucial to metabolism & energy balance. Found in liver & muscles.
- Dietary Fiber: no direct energy value but is important to dietary assets.
- Cellulose: helps move food mass along, stimulates normal muscle action.
- Lignin: binds cellulose fibers, gives strength to plants
- Noncellulose polysaccharide: slows food mass from the stomach
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Dissacharide
- Simple double sugars composed of two single-sugar units linked.
Sucrose: common table sugar; form of powdered/brown sugar; Glucose + Fructose Lactose: sugar in milk; formed in mammary glands; Glucose + Galactose Maltose: derived in the body from digestive breakdown of starch; used as a sweetener in processed foods; Glucose + Glucose
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Carbohydrate
(key concepts)
-provide practical energy sources because of their availability, low cost, & storage capacity
-structures vary from simple to complex, so they can provide both quick & extended energy for the body.
-Dietary fiber, and indigestible carbohydrate, serves separately as a body regulatory agent
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Carbohydrate
(Relation to Energy)
- - Energy is necessary for life. Need fuel for energy. Basic fuel source.
- - Sugars and starches are main source of energy
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Sugar Alcohols
Nutritive sweeteners that provide 2 – 3 Kcal per gram, sorbitol, mannitol and xylitol
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Sorbitol
Sugar alcohol formed in mammals fromglucose and converted to fructose
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Enzyme
Specific proteins produced in cells that digestor change specific nutrients in specific chemical reactions with out being changed themselves in the process
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Brush Boarder
Cells that are located on the microvilli within the lining of the intestinal tract
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Other Sweeteners
- Sugar alcohols andalternative sweeteners are often used assugar replacement.
- - Nutritive sweeteners- Sorbitol, mannitolxylitol are the alcohol form of sucrose
- - Nonnutritive sweeteners- aspartame andsaccharinOther
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Functions of Carbohydrates
- -Basic fuel supply- 4 Kcal/g
- Fuel for the body
- Burn in the body to meet energy needs
- -Special tissue functions
- Liver – Glycogen reserves in the liver and muscle – createreserves to protect cells form depressed metabolic function andresulting in injury
- -Protein and fat- Regulates protein and fat production-Proteins are broken down for source of energy if nocarbohydrates – Ketones are the by product - The Ketones are strong acids and creates acidosis. This upsets the acid base balance
- Heart – Fatty acids are the preferred fuel for the heart muscle. Glycogen is used in emergency situationsmay cause cardiac disorder and angina
- Central nervous system
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Food Sources for Carbs
- -Starches– fundamental complex carbohydrate foods for slowly available glucose
- -Sugars - not the villain in the story of health
- -Too much sugar
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Carbs (other)
- 1. Some starch is broken down by salivaryamylase to maltose.
- 2. Salivary amylase in inactivated by strong acid
- 3. Enzymes (amylase) from pancreas breakdown starch into maltose
- 4. Enzymes in wall of small intestine breakdown disaccharides sucrose, lactose and maltose into monosaccharide glucose, fructose, and galactose
- 5. Absorption of glucose, fructose andgalactose into blood stream to be takento the liver
- 6. Some soluble fiber is fermented intovarious acid and gases by bacteria in the large intestines
- 7. Insoluble fiber is excreted in feces, butlittle other dietary carbohydrate ispresent.
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Digestion of Carbs
- -mechanical and chemical
- -Mechanical is the process of chewing the food (mastication)
- -Pancreatic secretions are pancreatic amylasewhich breaks down disaccharides andmonosaccharides
- -Mouth– mixes with saliva and salivaryamylase (ptyalin) secreted by the parotidgland, located under ear and in back of jaw
- -Stomach- peristalsis wave like action of muscles fibers of the stomach wall
- Hydrochloric acid in the stomach stops the
- secretions of the parotid glands
- Small intestine – carbohydrate digestion iscomplete in the small intestines by enzymes secreted by the pancreas
- Intestinal secretions- sucrase, lactase, andmaltase they act in their respective disaccharideto create glucose, galactose and fructose
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Ethnicity & Lactose Intolerance
-African American and Native American suffer from lactose intolerance more than Caucasian.
-100% of Native Americans endure some form of lactose intolerance
95% of African American suffer with some form of lactose intolerance
12% Caucasian suffer from lactose intolerance
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