Download glucose

Soluble Fiber
• examples include gums, pectins, some
hemicelluloses
• functions:
– delay gastric emptying
– slow transit through the digestive system
– delay glucose absorption
– bind to bile, help decrease cholesterol
• food sources: fruits
1
Insoluble Fiber
• examples include cellulose, hemicellulose
• functions:
–
–
–
–
speed transit through the digestive tract
delay glucose absorption
soften stool to ease passage
reduces risk of hemorrhoids(‫(البواسير‬, diverticulitis
(‫(االنسدادات‬and appendicitis(‫)التهابات الزائدة الدودية‬
• food sources: cereal grains, legumes,
vegetables, nuts
2
DERIVED CARBOHYRATES
Oxidation
Products
Gluconic acid
Reduction
Products
Amino
Sugars
Deoxy
Sugars
Glycerol Glucosamine
Glucuronic acid Ribitol
Galactoseamine
Glucaric acid
Mannoseamine
Deoxyribose
“These are derived from carbohydrates by various
chemical reactions”
 Oxidation products
These reactions produce different products according
to the reagent used.
i-Bromine water; is a mild oxidizing reagent. It
selectively oxidizes the -CHO group into -COOH, and
converts aldoses to the corresponding aldonic acids
ii-Nitric acid; is a strong oxidizing agent. It oxidizes
both the -CHO and terminal -CH2OH of an aldose to COOH groups, and these dicarboxylic acids are
known as aldaric acids.
CHO
H
HO
CHO
COOH
OH
H
H
Br2/H2O
HO
OH
H
H
HO
COOH
OH
H
H
HNO3
OH
HO
H
H
OH
H
OH
H
OH
H
OH
H
OH
H
OH
H
OH
H
OH
CH2OH
Glucose
CH2OH
Gluconic acid
CH2OH
Glucose
COOH
Glucaric acid
iii-Controlled oxidation: this is carried out by first protecting the -CHO
group, followed by oxidation of the -CH2OH group to give alduronic
acid, e.g. oxidation of glucose into glucuronic acid.
 Reduction product
Aldoses and ketoses can be reduced with sodium
borohydride into the corresponding alditols.
Examples: glucose gives sorbitol (-CHO is converted to –OH),
mannose gives mannitol, galactose gives dulcitol.
6
This reduction occure under
hydrogen gas at aspecific pressure
and presence of Na/Hg as Chemical
catalyst or sodium borohydride
(NaBH4 ).
7
 Substitution products (Amino sugars)
• It is occur by specialized enzymes
•Where the replacement of a hydroxyl group in one of
the following groups:
•NH2
•CH3
•R-CO
Example: Replacing the hydroxyl group on the
second carbon atom in the glucose group with amine
group and produces a compound of glucose amine.
This compound is important for formation of
glycoprotein.
8
9
Regulation of Blood Glucose
Optimal functioning of the body is dependant on
keeping levels of glucose within certain
parameters.
Elevated blood glucose = Hyperglycemia
Low blood glucose = Hypoglycemia
The ENDOCRINE SYSTEM is primarily
responsible for regulating blood glucose. The
two main hormones are INSULIN and
GLUCAGON.
10
Regulation of Blood Glucose
11
Glucose —The most important carbohydrate
Function :
• Glucose can be converted into
• glycogen
• ribose
• galactose
• Glycoproteins — molecular targeting
• Antibodies and blood clotting factors(‫(عوامل تخثر الدم‬
• Structural components of cell membranes
Diseases associated with carbohydrates
• Diabetes mellitus
• Galactosemia
• Lactose intolerance
• Glycogen storage diseases
12
Diabetes Mellitus
• a disorder of energy metabolism due to
failure of insulin to regulate blood glucose
• results in hyperglycemia
• acute symptoms include thirst, increased
urine production, hunger
• long term consequences include increased
risk of heart disease, kidney disease,
blindness(‫)فقد البصر‬, neural damage
• two forms: Type I and Type II
13
Diabetes Mellitus
Type I
• accounts for about 10% of cases
• occurs when b cells of the pancreas are
destroyed
– insulin cannot be synthesized
• without insulin, blood glucose levels rise
because the tissues are unable to access the
glucose
• death occurs shortly after onset unless given
injections of insulin
14
Diabetes Mellitus
Type II
• occurs when cells of body are unable to
respond to insulin
• called “insulin insensitivity” or “insulin
resistance”
• blood glucose levels rise
• insulin secretion increases in an attempt to
compensate
– leads to hyperinsulinemia(‫)فرط افراز األنسولين‬
15
Hypoglycemia
• dramatic drop in blood glucose
• symptoms similar to an anxiety attack: rapid
weak heart beat(‫زيادة معدل ضربات القلب‬,
sweating(‫(تعرق‬, anxiety(‫(قلق‬, hunger(‫(جوع‬,
trembling(‫(ارتجاف‬, weakness(‫)ضعف‬
• RARE in healthy people
• may occur as a result of poorly managed
Diabetes or other causes:
– reactive hypoglycemia
– fasting hypoglycemia
16
The Glycemic Index
• a measure of the extent to which a food
raises blood glucose concentration &
elicits an insulin response compared to
pure glucose
Low
pasta
baked
beans bran
cereals
apples
milk
Moderate
banana
orange
juice
ice cream
High
white bread
cornflakes
potatoes
jelly beans
watermelon
17
The Glycemic Index cont.
Glucose
Baked potato
Jelly bean
Honey
Bagel
Sucrose
Boiled new potato
Brown rice
Chocolate
Boiled carrots
Orange
Spaghetti
Apple
Skim milk
Lentils
Fructose
100
85
78
73
72
65
62
55
49
47
44
42
38
32
29
23
18
The Glycemic Index cont.
The Theory…
• consuming foods with a low glycemic
index will minimize dramatic fluctuations in
blood glucose
• this reduces the need for insulin secretion
and may help manage Type II Diabetes
• eating several small meals frequently has
similar metabolic effects on blood glucose
as does consuming low glycemic index
foods
19