Question | Answer |
Carbohydrates are composed of? | carbon, hydrogen, and oxygen |
Empirical formula of carbohydrates is | (CH_2_O)n |
The two main classes of carbs are | simple sugars (soluble) and complex carbs or polysaccharides (large molecules like jelly and pectin) |
Carbohydrates are composed of? | carbon, hydrogen, and oxygen |
Empirical formula of carbohydrates is | (CH_2_O)n |
The two main classes of carbs are | simple sugars (soluble) and complex carbs or polysaccharides (large molecules like jelly and pectin) |
in plants simple sugars are a direct source of what? | energy which is formed by photosynthesis |
photosynthesis | CO_2_ + H_2_O = (CH_2_O)n |
complex carbs are used for | either storage forms of energy or structural components |
Sugar is not based on sweetness but | structure |
Monosaccharides | - are made up of 5 or 6 carbons
- contains a functional carbonyl group C=O
- and hydroxyl groups -OH |
What are some important Monosaccharides? | Glucose (GLU), Galactose (GAL), Mannose (MAN), and Fructose (FRU). |
These monosaccharides have different structures and functions but the same | number of atoms |
Disaccharides | sucrose, lactose, maltose |
Sucrose | glu-fru (table sugar 99.5% pure) |
Lactose | gal-glu (found in milk) |
Maltose | glu-glu |
Tri/tetrassacharides | raffinose, stachyose (found in plants and beans) |
Raffinose | gal-glu-fru |
stachyose | gal-gal-glu-fru |
linkages of sugars | sugar units in oligo- or polysaccharides are linked by a condensation between hydroxyls |
digestibility depends on | the chemistry of the linkage between sugars and the presence of enzymes in the intestine which can break that linkage |
Indigestible polysaccharides constitute | dietary fiber |
Properties of sugars | soluble in water, crystallize easily, sometimes sweet, react with proteins and amino acids to give brown colors and flabors (when heated like baking) |
Sweetness is related to | the 3d structure and depends on the position of oxygen atoms and hydroxyl groups |
Sweetness level | fructose > glucose > galactose > mantose (most bitter) |
Corn syrup | natural sweetener made from corn starch (a polymer of glucose) |
High fructose corn syrup is made by | isomerization of glucose |
Artificial and non-nutritive sweeteners | Saccharin, Aspartame - a dipeptide, acesulfame K |
Saccharin | 1st artificial sweetener |
Aspartame - A dipeptide | nutersweet / can't be used in heat process or it'll lose sweetness |
Acesulfame K | example: Splenda Chemical derivative |
Polysaccharides | polymer of sugar units n(s) --> (S)n |
n is usually | very large > 100 |
Starch | provides the most calorie (designed to be synthesized and broken down) |
Polysaccharides exist in two forms | amylose (linear) and amylopectin (branched) |
Is starch digestible | yes, it can form gels on cooling if the concentration is high |
Cellulose | all plants contain cellulose (resistant to digestion because of linkage) |
Pectin | is found in plant cell walls |
Pectins are polymers of | galacturonic acid which is indigestible |
Pectins can be strengthened by | cross linking with calcium |