Carbohydrates Flashcards
Carbohydrates
any of various neutral compounds of carbon, hydrogen, and oxygen (such as sugars, starches, and celluloses) most of which are formed by green plants and which constitute a major class of animal foods
provide you with energy for daily tasks and are the primary fuel source for your brain’s high energy demands
Fiber
special type of carb that helps promote good digestive health and may lower your risk of heart disease and diabetes
Monosaccharide
any of the classes of sugars (e.g. glucose, fructose, galactose) that cannot be hydrolysed to give a simpler sugar
Glucose
building block for starch, glycogen, cellulose, sucrose, lactose
name is 2,3,4,5,6-Pentahydroxyhexana
produced commercially via the enzymatic hydrolysis of starch
less water soluble than fructose
high glycaemic index values compared to fructose
sweetness lower than that of fructose
Fructose
found in honey, tree and vine fruits, flowers, berries, most root veg
name is 1,3,4,5,6-Pentahydroxy-2-hexanone
produced commercially from sugarcane, sugar beets, corn
most water-soluble sugar
lowest glycaemic index values of all natural sugars
sweetness greater than glucose + synergy effect when combined with other sweeteners
Sucrose
produced naturally in plants
disaccharide, composed of two monosaccharides: glucose and fructose
Starch
soft, white, tasteless powder that is insoluble in cold water, alcohol, or other solvents
basic chemical formula of the starch molecule is (C6H10O5)n.
polysaccharide comprising glucose monomers
simplest form of starch is the linear polymer amylose; amylopectin is the branched form
Cellulose
main substance found in plant cell walls
helps the plant to remain stiff and strong
Humans cannot digest cellulose, but it is important in the diet as a source of fibre. Cellulose is used to make clothes and paper.
Glycerol
colourless, odourless liquid with a sweet taste
viscous at room temperature and non-toxic in low concentrations
discovered in 1779
also called glycyl alcohol, glycerin or glycerine
Glycerol is seen in biological systems
intermediate in carbohydrate and lipid metabolism because surplus carbohydrate can be converted into long chain fatty acids and esterified with the three hydroxyl groups
can influence immune reactions in the body through histamines, increased antibody production and by enhancing immune cell activity and is therefore classified as an allergen.
In the blood, glycerol can increase blood pressure by preferentially attracting the water from tissues into plasma and lymph. In nephrons, glycerol can increase urine volume by preventing water resorption
Properties of Glycerol
Pure glycerol has a mp of 17.8°C
bp is 290°C
also decomposes at 290°C
presence of three hydroxyl groups makes the compound hygroscopic, with a tendency to absorb moisture from the air
= useful as a humectant in cosmetics and food, retaining water and preventing the substance from drying out
easily soluble in water, due to the ability of the polyol groups to form hydrogen bonds with water molecules
slightly denser than water with a specific gravity of 1.26
when glycerol is poured into a
container of water, it will sink to the bottom
due to its solubility, over time and with mild agitation, glycerol will form an aqueous solution
Uses of Glycerol
number of industrial applications
pharmaceutical
industry
cosmetics and personal care products
production of resins
detergents
plastics
tobacco
humectant (used to keep things moist)
in food
Glycerol Pharmaceutical
improve smoothness and taste
creation of tablets so that they are easy to swallow
coating can disintegrate within the body
Cough lozenges often use glycerol to give a sweet taste
Suppositories of glycerol can act as laxatives since they can irritate anal mucosa
Glycerol Structure
trihydroxy sugar alcohol with three carbon atoms and three hydroxyl groups
presence of multiple hydroxyl groups and carbon atoms makes it an organic polyol compound with the IUPAC name of 1, 2, 3 – Propanetriol
CH2(OH)CH(OH)CH2(OH)
