1 chapter 3 carbohydrates. 2 photosynthesis plants can make their own carbohydrates from the carbon...
Post on 18-Dec-2015
215 Views
Preview:
TRANSCRIPT
2
Photosynthesis
Plants can make their own carbohydrates from the carbon dioxide in the air and water taken from the soil.
Photosynthesis converts energy from sunlight into energy stored in carbohydrates, which the plants uses to grow and be healthy.
3
Categories of Carbohydrate
Simple carbohydrates Natural sugars Added (Refined)
sugars
Complex carbohydrates (polysaccharides) Starch Fiber
4
Functions of Carbohydrate
Functions as primary source of body’s energy Central nervous system and red blood cells
rely almost exclusively on glucose. Glucose is stored in liver and muscles as
glycogen. Spares protein from being burned for energy Helps body use fat efficiently Part of various materials in body, such as
connective tissue, some hormones & enzymes, and genetic material
6
Relative Sweetness of Sugars and Artificial SweetenersSweetener Rating
Sugars
Lactose 20
Glucose 70 – 80
Sucrose 100
High-fructose corn syrup 120 – 160
Fructose 140
Artificial Sweeteners
Aspartame (Nutrasweet, Equal) 160–220
Acesulfame-K (Sunette) 200
Saccharin (Sweet ’N Low) 200 – 700
Sucralose (Splenda) 600
Neotame 7,000–13,000
7
Added Sugars
Added sugars: Sugars added to a
food for sweetening or other purposes, do not include natural sugars
Examples: Granulated white sugar, high fructose corn syrup
8
Sugars on the Nutrition Facts Label
The number of grams of “Sugars” includes both natural and added sugars.
To find out if a food contains added sugar, look at the ingredient list.
9
Examples of Added Sugars
White sugar (sucrose) High-fructose corn syrup or corn syrup Invert sugar Brown sugar Molasses Honey Powdered sugar Raw sugar Demerara sugar
10
Added Sugars and Health
Dental caries (sugar & starch)
Obesity Diabetes Heart Disease Hypoglycemia Hyperactivity in Children
11
Glycemic Response
How quickly and how high your blood sugar rises after eating.
Eating mainly foods with a low glycemic response is important for people with diabetes and seems to decrease the risk of heart disease, type 2 diabetes, and colon cancer, as well as enhancing weight management.
12
Glycemic IndexGlucose
Corn flakes
Waffles, French-fried potatoes, jelly beans Bagel, white breadWhite sugar, cantaloupeRaisins, tortilla chips, cola soda, ice cream, pizzaRye breadOrange juiceFresh orange, peas, carrotsFresh peach, old-fashioned oatmeal, apple juiceWhite rice, spaghetti, apple, pear, tomato soupSkim milk, low-fat yogurtKidney beansGrapefruit
SoybeansPeanuts
13
Lactose Intolerance
An intolerance to milk and most milk products due to a deficiency of the enzyme lactase.
Symptoms often include flatulence and diarrhea within 30 minutes to 2 hours.
Especially prevalent among Asian Americans, Native Americans, African Americans, Latinos, and other groups.
Treatment requires a diet limited in lactose. Most people can drink small amounts of milk
especially if taken with food.
14
Complex Carbohydrate: Starch
Made of a long chain of glucoses linked together.
The glucose chains may be straight (amylose) or branched (amylopectin).
Found only in plant foods: grains, legumes, vegetables, some fruits.
Most starchy foods are cooked to make them flavorful and able to be digested.
Gelatinization – When starches are heated, they absorb water and swell in size.
16
Fibers
Polysaccharides found in plant foods that the body can’t digest or absorb.
Some fiber is digested by bacteria in the large intestine.
Two types: soluble or viscous fiber
insoluble or nonviscous fiber
17
Food Sources of Fiber
Soluble fiber1. Fruits
2. Legumes
3. Oats, barley, and rye
4. Also seeds and vegetables
Insoluble fiber1. Wheat bran, brown
rice, whole grains
2. Vegetables (cabbage, carrots)
3. Fruits
4. Legumes
18
Health Effects of Fiber
Soluble, viscous fiber Lowers risk of heart
disease & stroke by: Binding bile
Lowers risk of diabetes and controls diabetes by: Slowing glucose
absorption Also holds moisture in
stools, softening them
Insoluble, nonviscous fiber Alleviates constipation
and lowers risk of hemorrhoids and diverticulosis by: Increasing fecal
weight and speeding fecal passage through the colon
May help with weight management
19
If you decide to eat more fiber…..
Do so slowly and Drinks lots of fluids
to give time for your intestine to adapt.
20
Whole Grains
Examples: Whole wheat Whole rye Oatmeal Whole oats Whole hulled barley Popcorn Brown rice
Whole grains offer: More nutrients Phytochemicals More fiber
Dietary Guidelines for Americans recommends 3+ servings of whole grains each day.
21
Digestion, Absorption, & Metabolism of Carbohydrates
Starch digestion begins in mouth. (enzyme-salivary amylase)
Before being absorbed, carbohydrates must be broken down into monosaccharides.
Enzymes in small intestine (sucrase, lactase, maltase, and pancreatic amylase) ensure that single sugars are absorbed.
In the liver, fructose and galactose are converted to glucose or further metabolized to make glycogen or fat.
22
Dietary Reference Intakes
RDA for carbohydrate – 1 year old + 130 grams daily
(minimal amount – you really need 2x) AMDR – 1 year old + 45-65% of kcalories
AI for total fiber 14 g/1000 kcal Men 19 – 50 years old 38 g Men over 50 years old 30 g Women 19 – 50 years old 25 g Women over 50 years old 21 g
DRIs – added sugars < 25% of total kcalories
23
Low-Carb Foods
To reduce carbohydrates, manufacturers: Substitute soy flour, soy protein, or wheat
gluten (all higher in protein) for refined flour Substitute artificial sweeteners and/or sugar
replacers (also called polyols) for sugars Add fiber such as wheat bran Add high-fat ingredients such as nuts to
improve flavor and/or add bulk
24
5. Sugar Replacers or Polyols
A group of carbohydrates that are sweet and occur naturally in plants.
Examples: sorbitol, xylitol found in sugar-free gums and candy.
25
5. Sugar Replacers or Polyols
Benefits: Don’t provide as many kcalories as sugar –
only about 2 kcal/gram. Don’t promote tooth decay. Taste sweet – though not as sweet as sugar. Add bulk and texture to foods. Cause smaller increases in blood sugar and
insulin than sugar. Side effects
26
Sugar Replacers or Polyols
Sugar Replacer
Kcal/gram Uses Description*
Mannitol 1.6 Chewing gum, powdered foods, chocolate coatings
•50 to 70% as sweet as sugar.•May causes a laxative effect when 20 grams or more are consumed •Does not absorb moisture so it works well as a dusting powder for chewing gum so the gum doesn’t stick to the wrapper.
Sorbitol 2.6 Candies, chewing gum, baked goods, frozen desserts
•60% as sweet as sugar. gum, baked goods,•May cause a laxative effect when 50 frozen desserts grams or more are consumed.•Cool, pleasant taste.
27
Sugar Replacers or Polyols (cont’d)
Xylitol 2.4 Chewing gum, candy
•As sweet as sugar.•Pleasant taste.
Erythritol 0.2 Beverages, chewing gum, candy, baked goods
•Newest polyol.•Very heat stable.•Much less of a laxative effect than other polyols.•Works well with other sweeteners to improve flavor and body.
Isomalt 2.0 Candies, toffee, fudge, wafers
•45 to 60% as sweet as sugar.•Used to add bulk and sweetness to foods.•Very heat stable.•Works well with other sweeteners to improve flavor.
28
Sugar Replacers or Polyols (cont’d)
Lactitol 2.0 Chocolate, candies, cookies and cakes, frozen dairy desserts.
•30 to 40% as sweet as sugar.•Mild sweetness with no aftertaste.•Used to add bulk and sweetness to foods.•Works well with artificial sweeteners.
Maltitol 2.1 No-sugar added ice cream, low-carb bagels, candy, chewing gum, chocolate, baked goods.
•90% as sweet as sugar.•Used to add bulk and sweetness to foods.
29
Sugar Replacers or Polyols (cont’d)
Hydrogenated Starch Hydrolysates
3.0 Candy, baked goods
•25 to 50% as sweet as sugar.•Used as bulk sweetener in low calorie foods. Performs other functions in foods as well.•Can mask unpleasant off-flavors.•Blends well with flavors. •Works well with other sweeteners.
*All sugar replacers have the following characteristics:• Occur naturally.• Don’t provide as many kcalories as sugar. The average kcalories per gram is 2, compared with 4 kcalories/gram from sugar. • Don’t promote tooth decay.• Cause smaller increases in blood glucose and insulin levels than sugar.
31
Artificial Sweeteners
Approved Saccharin Aspartame Acesulfame-K Sucralose Neotame
Possibilities Alitame Cyclamate Stevioside
Reduced-Kcal Sweetener Tagatose
top related