Topic 4: Part B Flashcards
Carbohydrates (CBO) includes
sugars, starches and fibres
Carbs consist of..
carbons, hydrogen, oxygen
Carbs are formed in ..
green plants through photosynthesis whereby the sun energy converts carbon dioxide form atmosphere and water form soil into glucose
Oxygen is given off by the ..
plant during photosynthesis
Carb foods include
- Cereal grains and flours (wheat, rye, corn)
- Legumes (pease, beans, lentils)
- Starchy roots or tubers, (potatoes, yam cassava)
- Fruits (orange, apple, banana)
- Sugars, honey, jams, molasses.
- Milk products
Carb are classified according to number of ..
basic sugar (saccharide) units
4 types of carbs and how many sugars are in them
- Monosaccharides- simple sugars, _1 unit.
- Disaccharides- simple sugars, 2 units.
- Oligosaccharides- simple sugars, 3-10 units.
- Polysaccharides- complex sugars, many units.
Monosaccharides
include 6 carbon hexose and 5 carbon pentose
Hexose
Hexose sugars such as glucose, mannose, fructose and galactose are building blocks of polysaccharides.
Pentose
Pentose sugars such as ribose, xylose and arabinose are the building blocks of fibers and gums.
Glucose
- most abundant sugar in the world
- found in fruits, plant juices and honey
- present w other sugars
The form of glucose that circulates the bloodstream, it is broke down in the body to give 3 products
- energy
- water
- carbon dioxide
Many complex carbs such as starch and cellulose have..
glucose as basic unit
Glucose is major component of corn syrup which is formed by
hydrolysis of starch
Corn syrup and crystalline glucose are widely used in
baking industry
Fructose
- found in fruits, plant juices and honey
- sweetest of all common sugars
- very soluble and doesn’t crystallize easy
In food industry glucose is changed too..
fructose by addition of enzyme glucose isomerase
High fructose corn syrup
glucose changed to fructose and sweetener used in soft drinks
Galactose
- not found in its free from in foods
- forms bond with glucose to produce lactose (milk sugar)
- basic unit off some complex carbs such as vegetable gums
Some galactose is found in ..
freeform in fermented milk products where hydrolysis of lactose has occurred
Disaccharides
-consist of 2 monosaccharides linked together
Common disaccharides in food are..
sucrose (cane/beet sugar), maltose from corn syrup and lactose from milk
Disaccharides are not absorbed into ..
the bloodstream from small intestines and hence are not available as energy sources to human body
Disaccharides must be hydrolyzed to ..
monosaccharides which then can be absorbed ti bloodstream
Non-hydrolyzed disaccharides pass through the ..
small intestine to the large intestine where they are hydrolyzed by bacteria to produce acetic and lactic acids/gases
When produced in sufficient quantities these acids form disaccharides have a..
laxative effect and cause dirrahea (gas production can cause flatulence and abdominal cramps/discomfort)
Sucrose
- table sugar
- extracted from sugar cane and beets.
- consists of glucose and fructose chemically bonded
- present w other sugars in fruits, honey and vegetables
Lactose
- milk sugar
- consists of glucose and galactose chemically bonded to each other
- only found in milk and products of milk
Maltose
- found in germinating grain, corn syrup
- product pf starch hydrolysis
- important of production of malted beverages
- consists of 2 glucose molecules chemically bonded to each other
Oligosaccharides
- carb molecules that contain 10 or fewer monosaccharides
- includes raffinose and stachyose
- gas formation (commonly found in dried beans)
- not digested by humans but broken down by bacteria in intestinal tract resulting in gas formation
Polysaccarides
- complex carbs
- up 2 several hundred thousand monosaccarides joined together
- homoglucans are composed of the same type of monosaccharides
Heteroglucans are composed of ..
at least 2 types of monosaccharides (may be straight chains or highly branched chains)