PCOG - Carbohydrates

Carbohydrates

Source of energy

Cn (H2O)n

Carbohydrates General Formula

Photosynthesis

Biosynthesis of Carbohydrates

1. Light reactions

2. Dark reactions

2 Types of photosynthetic reactions in green plants

Light reactions

that actually convert electromagnetic energy into chemical potential.

Dark reactions

consists of the enzymatic reactions that utilize the energy from the light reactions to fix carbon dioxide into sugar.

Photosynthetic carbon reduction cycle or the Calvin cycle.

Also called the dark reaction or light-independent reaction.

Photosynthetic carbon reduction cycle or the Calvin cycle.

Convert CO₂ into carbohydrates (glucose precursors).

1. Fixation

2. Reduction

3. Regeneration of acceptor

three stages of CO2 fixation in photosynthetic organisms.

Monosaccharides

Oligosaccharides

Polysaccharides

Classifications of Carbohydrates

Monosaccharides

compounds that cannot be hydrolyzed to simpler sugars

Triose (ex. Glyceraldehyde)

3 Carbon Carbohydrates

Tetrose (ex. Erythrose)

4 Carbon Carbohydrates

Pentose (ex. Ribose, Xylulose)

5 Carbon Carbohydrates

Hexose (ex. Glucose, Fructose, Mannose)

6 Carbon Carbohydrates

Heptose (ex. Sedoheptulose)

7 Carbon Carbohydrates

Nonose (ex. Neuraminic acid)

9 Carbon Carbohydrates

Ribose and Xylulose

products of hydrolysis of hemicelluloses, gums and mucilages

Gluc, Fruc, Mann

most important monosaccharides found in plants

D-xylose

Monosaccharide used as a diagnostic agent to evaluate intestinal absorption.

Wood sugar

Synonym/s of D-xylose

Corn cobs, straw (Xylan—a hemicellulose) + Dilute Acid

Source of D-xylose

D-glucose

Monosaccharide natural in grapes

Grape sugar

Dextrose

Blood sugar

Synonym/s of D-glucose

Dextrates

Product containing glucose obtained by controlled enzymatic hydrolysis of starch

Liquid glucose

Product containing glucose obtained by the incomplete hydrolysis of starch. Usually prepared by controlled acid hydrolysis of corn starch.

Reduction

All monosaccharides can undergo this reaction

Fructose

sweetest naturally occurring sugar

Levulose

Fruit sugar

Synonym/s of Fructose

• Sweet fruits

• Honey

• Inversion of aqueous solutions of sucrose.

• obtained from enzymatically prepared high-fructose syrup

• from the hydrolysis of inulin

Sources of Fructose

High-fructose sweeteners

prepared by controlled enzymatic isomerization of glucose.

Galactose

Monosaccharide rapidly absorbed in the small intestine and can cause Galactosemia (presents with jaundice-like symptoms.)

Brain Sugar

Synonym/s of Galactose

Disaccaharide

yield 2 monosaccharide molecules on hydrolysis

Cane Sugar

Beet Sugar

Table Sugar

Synonym/s of Sucrose α (1,4)

fruit juices, sugar cane, sugar beet, the sap of certain maples

Sources of Sucrose

invert sugar

Upon hydrolysis sucrose yields…

Sacharum officinarum Linne (Fam. Graminae)

Beta vulgaris Linne (Fam. Chenopodiaceae )

Acer saccharum ( Fam. Aceraceae)

Plant sources of Sucrose

Sucrose

glucose + fructose

Maltose

glucose + glucose (Enzymatic hydrolysis of starch)

cellobiose

glucose + glucose (Enzymatic breakdown of cellulose)

trehalose

glucose + glucose (From Ergot, rhodophyceae, yeasts)

sophorose

glucose + glucose (From Sophora japonica, Leguminosae hydrolysis of stevioside)

primeverose

glucose + xylose

Lactose

Also known as Milk Sugar

Cow’s milk

is the fresh, unpasteurized, or pasteurized milk of Bos taurus Linne (Fam. Bovidae), without modification

lactose

glucose + galactose

Lactulose

alkaline rearrangement of lactose

Lactulose

fructose + galactose

Lactulose

metabolized by colonic bacteria to acetic and lactic acids, which produce an osmotic laxative effect.

Gentianose (From Gentiana spp.)

2Glucose + Fructose

Raffinose (From cottonseed)

Glucose + Galactose + Fructose

melezitose (Manna from Larix)

glucose + fructose + glucose

planteose (Seeds of Psyllium spp)

glucose + fructose + galactose

manneotriose (Fraxinus ornus, Oleaceae ash)

galactose + galactose + glucose

rhamninose (Rhamnus infectoria)

rhamnose + rhamnose + Galactose

scillatriose (Glycoside of squill)

rhamnose + glucose + glucose

Stachyose

Tetrasaccharide example

Stachyose (Tubers of Stachys japonica, Lamiaceae)

2 Galactose + Glucose + Fructose

Raffinose

Most important non-reducing trisaccharide

succus cerasi

Latin term of Cherry Juice

Prunus cerasus Linne (Rosaceae)

Source of succus cerasi (cherry juice)

1% malic acid

succus cerasi has nlt

Cherry Juice

used in cherry syrup, flavored vehicle especially to those acidulous nature

Oxidation of Sugar (RCOH → R-COOH)

How are plant acids created?

Citric Acid

tricarboxylic acid

Carl Wilhelm Scheele

Who’s responsible for isolation of

Citric Acid

Citric Acid

useful in buffering systems.

Citric Acid

acidulant in effervescent formulations

Lactic acid

It is obtained by the lactic fermentation of sugars or is prepared synthetically.

Lactic acid

used as an acidulant, especially in infant feeding formulas.

ethanedioic acid

Systemic name of Oxalic acid (C2H2O4 (anhydrous); C2H2O4.2H2O (dihydrate))

Oxalic acid

Plant acid used as Bleaching agent

butane dioic acid or ethane-1,2-dicarboxylic acid

Chemical name of succinic acid (C4H6O4)

Malic acid

Plant acids found in Apple (Malus domestica)

2-Hydroxybutanedioic acid

Chemical name of malic acid (C4H6O5)

diHydroxybutane dioic acid

Chemical name of Tartaric acid (C4H6O6)

Tartaric acid

is a dicarboxylic acid, obtained as a by-product of the wine industry

Tartaric acid

used as a substitute for citric acid in buffer systems and in effervescent formulations

Ferrous fumarate

a hematinic agent that is comparable to ferrous gluconate, the usual therapeutic dose is 200mg 3-4x a day

Alcohol or ethanol

is a liquid containing not less than 92.3% by weight, corresponding to 94.9% by volume, of ethanol at 15.56C

Mannitol or D- mannitol

hexahydric alcohol

laxative

diagnostic aid and as an osmotic diuretic

Mannitol

isolated from manna Fraxinus ornus Linne (Fam. Oleaceae)

Fraxinus ornus Linne (Fam. Oleaceae)

from what source is Mannitol isolated from

Mannitol

obtained by reduction of mannose

Sorbitol or D–glucitol

hexitol

obtained from the ripe berries of mountain ash, Sorbus aucuparia (Fam. Rosaceae)

Reduction of Glucose

Reduction of glucose can form what sugar alcohol

Sorbitol or D-glucitol

tastes approximately half as sweet as sucrose

Sorbus aucuparia (Fam. Rosaceae)

What ripe berries can Sorbitol be obtained from

Sorbitol or D–glucitol

humectant in creams