Nutrients in food-AAAC

Nutrients in Food
Culinary consultants
Concept Developers
Food Designers

The Six Major Nutrients in
Food,
 Carbohydrates,
 Lipids (fats/oils)
 Proteins
 Mineral salts (eg. Ca, Fe and K compounds)
 Vitamins (eg. Vitamin C & D)
 Water

Carbohydrates
 Function
 Energy source
 Dietary Fibre
 Typical Sources
 Potatoes Honey
 Bread Celery

Lipids (Fats & Oils)
 Function
 Energy source
 Typical Sources
 Margarine
 Butter
 Oils

Proteins
 Function
 Growth & repair of tissues
 Control of reactions
 Energy source
 Typical Sources
 Meat Fish
 Broad beans Lentils

Mineral Salts
 Function
 Various specialised roles
 Typical Sources
 Meat
 Vegetables
 Dairy products

Vitamins
 Function
 Various specialised roles
 Typical Sources
 Milk
 Meat
 Vegetables
 Fruit

Water
 Function
 Solvent
 Transport agent
 Hydrolysis reactions
 Typical Sources
 Drinks
 Fruit
 Vegetables

Human Digestive System
 Mouth
 Food is chewed into small pieces
 Food begins to react
 Reaction catalysed by enzymes in saliva
 Stomach
 Food is further broken down in combined action of
hydrochloric acid and enzymes present in gastric juice

 Small Intestine
 Mixture of enzymes act on the food
 Enzymes come from pancreas & wall of duodenum
 Simple substances produced are absorbed into blood
stream and transported to various parts of the body

 Large Intestine
 Water is absorbed from remaining undigested food
 Undigested food contains large proportion of dietary fibre
 Bacteria in colon ferment some of the fibre producing
useful small molecules
 These are absorbed into bloodstream
 Remaining undigested matter is excreted

Chemical Processes Occuring to
Digested Food
Polysaccharides
(starch)
Fats
Proteins
Monosaccharides
Fatty acids
Amino Acids
Glycogen
Fats
Proteins
Digestion (Hydrolysis
using enzymes
Absorption
Food containing large
molecules
Small molecules
Immediate use as an
energy source
(Condensation using
enzymes)
Large molecules for storage or
other purposes

Carbohydrates : Composition
and Occurrence
 Carbohydrates make up more than 50% of organic
matter found on earth and are the major component of
plants.
 They contain the elements carbon, hydrogen and
oxygen and usually have the formula Cx(H2O)Y (where x
and y are whole numbers).

Carbohydrates
 They range in size from small molecules to very large
polymers and can be classified as:
i) monosaccharides (e.g. glucose)
ii) disaccharides (e.g. sucrose)
iii) polysaccharides (e.g. cellulose)

Carbohydrates
 Typical food sources include bread, cereals, honey,
potatoes, grains, flours, Pastries etc.
 Detailed knowledge of carbohydrate structures (e.g.
valence structures) is not required in this area of study.

Monosaccharides
 These are the simplest carbohydrates
 (mono = one)
 are sweet, white solids which are very soluble in water.

Monosaccharides
 Glucose,fructose and galactose all have the same
molecular formula (C6H12O6)
 but their structures, all of which are cyclic, are slightly
different;
 they are examples of structural isomers.
 A pictorial structure diagram of glucose and galactose
may be drawn as (a hexose) and that of fructose
drawn as (a pentose).

Monosaccharides
 All three isomers contain a number of hydroxy (-OH)
groups in their cyclic
structures
 hydrogen bonding exists between monosaccharide
molecules and solvent water molecules
 this enhances their solubility.

Glucose
 the most abundant monosaccharide, is found in all living
things, including animal tissue, plant sap and fruit
Juices.
 It is a key energy source and also a monomer (building
block) for other more complex carbohydrates.

Fructose
 The sweetest natural sugar known, is present in honey
and many fruit Juices.
 It is a key energy source and monomer of more complex
carbohydrates.

Galactose
 while not found as a free monosaccharide, is a common
monomer of more complex carbohydrates.

Structure of Glucose
H
H
H
H
H
CH2OH
OH
OH
OH
HO

Structure of Galactose
H
H
H
H
H
CH2OH
OH
OH
OH
HO

Structure of Fructose
H
H
H
CH2OH
HO
HO
HO
HOCH2

Disaccharides
 These consist of 2 (di=two) monosaccharide molecules
which have reacted and have been chemically linked
together
2 C6H12O6(aq)  C12H22011(aq) + H2O(1)

Disaccharides
 This is an example of Condensation Reaction
 Where molecules react and chemically bond together
with the elimination of a small molecule (H2O in this
case)
 Condensation also because water is produced

Disaccharides
 The reverse reaction is:
C12H22O11 (aq) + H 2O(1)  2C 6H 12O 6 (aq)
 This reaction occurs in the body with acids or enzymes
and is called a hydrolysis
reaction (i.e. reaction with water).

Disaccharides
 The most important disaccharides in terms of diet are
 Sucrose
 Maltose
 Lactose.

Sucrose
 Formed from glucose and fructose monomer units
 Commonly extracted from sugar cane and is known as
cane or table sugar.

Sucrose
 A pictorial structure diagram of a sucrose molecule may
be drawn as:
 G = Glucose F = Fructose
G F

Maltose,
 Formed from the two glucose monomer units,
 Is known as malt sugar and
 Is present in germinating grain.
 The pictorial structure diagram of a maltose molecule
may be drawn as:
G G

Lactose,
 formed from glucose and galactose monomer units,
 the main carbohydrate found in milk and is known as
milk sugar.
 pictorial structure diagram of a lactose molecule may
be drawn as:
G = Glucose Ga = Galactose
G Ga

Polysaccharides
 When monosaccharides react together, there is a
reaction between some of the hydroxy (-OH) functional
groups.
 When two neighbouring -OH groups interact, a water
molecule is eliminated and a new covalent bond is
formed.

Polysaccharides
 This type of reaction where functional groups react
together and a small molecule is eliminated is a
"condensation" reaction.

Polysaccharides
 The new covalent bond (a strong bond) holds the
previously separate monomers together to form a larger
molecule -this now linkage is termed an "ether linkage."

Polysaccharides
 This can be illustrated in the following diagram.
CH2OH
O O
OOH
H
H H
H
H
CH2OH
HH
H H
H
OH OH
OH OH
OH

Polysaccharides
 This can be illustrated in the following diagram.
CH2OH
O O
OOH
H
H H
H
H
CH2OH
HH
H H
H
OH OH
OH OH
OH
Ether link

Polysaccharides
 These are polymers formed from simple sugars by
condensation polymerisation reactions and which have a
backbone consisting of C and H atoms:
e.g. n C6H1206 (C 6H1005)n + n H2O
monosaccharide polysaccharide
(n = a very large whole number)

Polysaccharides
 They are very large molecules with high molar masses
and, in general, have no taste nor are they soluble in
water.
 Three important examples are
 starch,
 cellulose
 glycogen.

Polysaccharides
 A general pictorial structure diagram of a section of
polysaccharide may be
drawn as:

Starch
 has a major role in storage of carbohydrates (glucose) in
plants
 It provides energy requirements at night when there is
no photosynthesis.
 is obtained in foods such as cereal grains, potatoes and
rice.

Cellulose
 is the major structural material in plants and, thus, has
a significant abundance in the biosphere.
 It is present in such common foods as cereals, fruits and
vegetables
 plays a significant role in dietary needs as dietary
fibre/roughage.

Glycogen
 a soluble polysaccharide which has a
major role of
 glucose storage in animals as energy is
required,
 glycogen undergoes a hydrolysis
reaction producing glucose and
providing energy.
 This is effectively the reverse of the
condensation polymerisation e.g.
( C6H10O5 )n + n H2O .n C6H12O6

Digestion of Polysaccharides
 Starch and glycogen can be broken down with enzymes
in hydrolysis reactions to form maltose (a disaccharide)
and ultimately glucose (a monosaccharide) which is
absorbed in the body.
 A general diagram can be drawn as follows:

Starch or Glycogen
Glucose
Maltose
Enzyme catalysed hydrolysis during
digestion
Enzyme catalysed hydrolysis during
digestion

 Most cellulose is not broken down by our digestive
systems but, as mentioned above, is utilised as dietary
fibre/roughage which of great benefit to the proper
functioning of our bodies.

Composition and Occurrence
 Lipids mainly contain the elements carbon and hydrogen
with small amounts of oxygen and sometimes other
elements.
• Most are essentially non-polar so they tend to
dissolve in non-polar solvents but not in polar solvents
such as water.
• Fats and oils are the most common lipids with fats
being solid at normal temperatures whereas oils are
liquids.

Lipids (Fats and Oils)
 Typical food sources include oils, butter, margarine,
some meats, nuts etc.
 Their major role is as an energy source and to provide
insulation - fats/oils provide more than twice as much
energy, per gram, as carbohydrates or proteins.

Formation of Lipids
 Most fats/oils are produced by a condensation reaction
between a glycerol molecule and 3 fatty acid
molecules;
 in this reaction, water is released and the product of
the reaction is referred to as a triglyceride.
 An example is shown below:

Formation of Lipids
H
OHH C
OHH C
OHH C
H
glycerol

Formation of Lipids
H
OHH C
OHH C
OHH C
H
glycerol
OH C R
+
O
OH C R
O
OH C R
O
3 fatty acid
molecules

Formation of Lipids
H
OHH C
OHH C
OHH C
H
glycerol
OH C R
+
O
OH C R
O
OH C R
O
3 fatty acid
molecules
H
OHH C
OHH C
OHH C
H
OH C R
O
OH C R
O
OH C R
O

Formation of Lipids
H
OHH C
OHH C
OHH C
H
glycerol
OH C R
+
O
OH C R
O
OH C R
O
3 fatty acid
molecules
H
OH C
OH C
OH C
H
C R
O
C R
O
C R
O
+ 3 H2O

Formation of Lipids
H
OHH C
OHH C
OHH C
H
glycerol
OH C R
+
O
OH C R
O
OH C R
O
3 fatty acid
molecules
H
OH C
OH C
OH C
H
C R
O
C R
O
C R
O
+ 3 H2O
A triglyceride

Classification of Fats
 This depends on structural features of the fatty acid
from which the fat (triglyceride) is made.
 a) Saturated fats
 The fatty acid contains C-C single bonds only.
 These fats are generally waxy, unreactive solids.

Classification of Fats
 b) Mono-unsaturated fats
 The fatty acid contains one C=C (double bond).
 c) Poly-unsaturated fats
 The fatty acid contains more than one C=C double bond.
 These are often liquids and are more reactive.

Digestion of Fats
 This occurs mainly in the small intestine
where bile (produced in the liver and
stored in the gall bladder) converts the
fat into an emulsion.
 Enzymes catalyse the hydrolysis of fat
back to glycerol and fatty acids (once
again, the reverse of the condensation
reaction); these small molecules are
absorbed by the body.
 After absorption, these are re-converted
by enzymes into triglycerides (in a
condensation polymerisation reaction).

Functions of Lipids
 Fats are used by the body as
 i) an energy source
 ii) a heat insulator
 iii) a shock insulator (for internal organs),

Phospholipids,
 an important group of complex lipids,
form the main constituent of cell
membranes.
 are complex lipids, which together
with proteins, make up the major
components of cell membranes.
 Like fats, phospholipids are also esters
of glycerol but they contain only two
fatty acids.
 The third carbon atom from the
original glycerol molecule is attached
to a phosphate group.

Structure of Palmitic Acid,
 A Saturated Fat
 CH3 (CH2)14 COOH

Structure of Aleic Acid
 A Mono Saturated Fat
 CH3 (CH2)7 CH ==CH (CH2)7 COOH

Structure of Linoleic Acid
 A Polyunsaturated Fat
CH3 (CH2)4 CH ==CHCH2CH==CH (CH2)4 COOH

Composition and Occurrence
 Proteins are of major importance, being present in
every cell and crucial to both cell structure and
functioning.
 They comprise between 15% and 20% of the human
body, contributing an average of 67% of the dry weight
of cells.

Proteins
 There are many hundreds of different types of proteins
which have specific purposes either as the basic
structural material for the repair and growth of tissues
or in the body's metabolism.
 They contain the elements carbon, hydrogen, nitrogen,
oxygen and often sulphur.

Functions of Proteins
 The main function of proteins is for building new tissues
and maintaining existing tissues.
 Apart from this role they play a crucial part in the
body's metabolism.

Functions of Proteins
 Cells use proteins in a range of ways -
 to act as biological catalysts (enzymes),
 in communication through nerves,
 in regulation of the body's metabolism with hormones,
 as haemoglobin in the transport of oxygen in the blood and
 as protective agents against disease.

Protein Monomers
 Proteins are polymers (very large molecules) that are
composed of large numbers of smaller molecules called
monomers.
 The monomers from which proteins are constructed are
called "a-amino acids".

Amino Acids
 are named as such (i.e. as "a" because the
amino (-NH 2) functional group is on the first
carbon atom that is bonded to the carboxyl
(-COOH) functional group.
 They are also known as 2-amino acids with
the first carbon being the carbon that is part
of the carboxyl (-COOH) functional group and,
thus, the amino (-NH 2) functional group is
attached (bonded) to the second carbon
atom.
 they will be referred to as a-amino acids for
simplicity.

Amino Acids
 The general formula of an a-amino acid is:
 where Z represents an organic group.
Z
C C
NH2
H
OH
O

Amino Acids
 a-amino acids contain a carboxyl group (-COOH) and an
amino group (-NH 2) on the next carbon atom.
 Two simple a-amino acids are:

Glycine
H
C C
NH2
H
OH
O
Z = H

Alanine
CH3
C C
NH2
H
OH
O
Z = CH3

Amino Acids
 Unlike animals and humans, plants can manufacture all
their required amino acids from inorganic ingredients.

Non Essential Amino Acids
Humans are able to internally manufacture only 11 of the
20 amino acids which are necessary to produce the
range of required proteins -
those 11 are referred to as non-essential amino acids
because an external food source is not required for
their production.

Essential Amino Acids
The remaining 9 amino acids needed for protein synthesis
must be provided by our food intake.
They are referred to as essential amino acids because an
external food source is required to obtain them.

Functional Groups
The carboxyl group (-COOH) and amino (-NH 2) group are
examples of "functional groups".
These are a small group of atoms that attach to a longer
organic 'backbone' and which give the organic molecule
particular properties (or 'functions').

Carboxyl Group (COOH)
The carboxyl group (-COOH) is found in a family of organic
compounds called 'carboxylic acids'; the -COOH group
can act as an acid.

Amino Group (NH2)
The amino group (-NH2) is found in another family of
organic compounds called ' amines';
the -NH2 group can act as a base.

Amino Group (NH2)
As mentioned above, every amino acid contains two
functional groups - an amino group (-NH 2) and a
carboxyl group (-COOH).
The amino group can act as a weak base (H+ acceptor)
whereas the carboxyl group can act as a weak acid (H+
donor).

Alanine
In a low pH solution (acidic solution), the amino group,
being a base, will react with the acid in solution, accept
a hydrogen ion and form -NH +

Alanine
For example, the structural formula for alanine is usually
drawn as:
CH3
C C
NH2
H
OH
O

Alanine in Acidic Solution
In a low pH (acidic) solution, the structural formula for
alanine will be:
(NB: the amino acid exists as a cation in the low pH
Solution)
CH3
C C
+NH3
H
OH
O

Alanine in Basic Solution
In a high pH solution the carboxyl group, being an acid, will
react with the base in solution and donate a hydrogen
ion and form the anion -COO- (aq).
CH3
C C
NH2
H
O--
O

Alanine in Intermediate pH
In a solution with intermediate pH, there is not a strong
acid or base in solution
to react with acidic carboxyl group (as in the high pH
example) or the basic amino group (as in the low pH
example).

The structure of the a-amino acid is such
that the amino group is close to the
carboxyl group and an
"Intra-molecular" acid-base reaction
(H+ transfer) occurs.
The carboxyl group (-COOH) donates H+
to the amino group (-NH2) producing
both -COO- and -NH3
+ on different
parts of the same molecule.

Thus, the structural formula for alanine in a solution with
intermediate pH will be:
NB: the amino acid exists as a
"zwitter-ion" in the intermediate pH
solution - i.e. a molecule with no
net charge (neutral) but with
specific charged parts within it).CH3
C C
NH3
+
H
O--
O

Formation of Proteins
 Proteins are formed by a reaction between amino acids
(often called peptides) -
 this is an example of a condensation polymerisation
reaction in which water is eliminated (the same type of
reaction in which monosaccharides form
polysaccharides).

Condensation Reaction
 An example of the condensation reaction between 3
different a-amino acids is shown below:

NH
H
C C
O
OH
Z1
NH
H
C C
O
OH
Z2
NH
H
C C
O
OH
Z3

NH
H
C C
O
OH
Z1
NH
H
C C
O
OH
Z2
NH
H
C C
O
OH
Z3
NH
H
C C
O
Z1
N
H
C C
O
Z2
N
H
C C
O
OH
Z3

NH
H
C C
O
OH
Z1
NH
H
C C
O
OH
Z2
NH
H
C C
O
OH
Z3
NH
H
C C
O
Z1
N
H
C C
O
Z2
N
H
C C
O
OH
Z3
Peptide Links

Copolymers
 The copolymers produced by the
condensation reactions of amino acids
(peptides) are called polypeptides; if
more than 50 amino acid units are
present, the polypeptide is referred to
as a protein.
 The simplest protein is the hormone
insulin (which plays an important role
in controlling the level of blood sugar);
this protein contains 51 amino acid
units.

Formation of Proteins
 An example of a polypeptide (protein) chain showing
the peptide linkages is given below:

Polypeptide (Protein)
H
C
CH2
CH3
C
O
N
H
H
C
CH2
CH2
C
O
N
H
H
C
CH2
SH
C
O
N
H
H
C
CH2
CH2
C
O
N
H
OH OH

Polypeptide (Protein)
H
C
CH2
CH3
C
O
N
H
H
C
CH2
CH2
C
O
N
H
H
C
CH2
SH
C
O
N
H
H
C
CH2
CH2
C
O
N
H
OH OH
Peptide Links

Proteins
 Proteins differ with respect to the number, type and
sequence of their constituent amino acids.

Protein Structure
 Each protein performs a particular function in the body.
 A significant aspect of chemical functions of proteins
relates to their structure which needs to be considered
on three levels in what is termed "primary structure',
'secondary structure' and tertiary structure'.

Primary Structure
 The 'primary structure' of proteins refers to
the number and sequence of amino acids in
the polypeptide chain.
 The human body is thought to contain over
one hundred thousand different proteins and
these, as mentioned above, are constructed
from only 20 different amino acids!
 This situation is often compared to the
existence of only 26 letters in the English
alphabet but the enormously large number of
words that can be formed with these 'building
blocks'.

Secondary Structure
 The of proteins refers to the coiling, folding or pleating
of the protein chains into particular three-dimensional
arrangements.
 This is due to the attractive forces of the dipoles
present in the polar -CO and -NH sections of the
polypeptide backbone - this involves "hydrogen
bonding'.

Tertiary Structure
 The of proteins refers to the manner in
which the coiled polypeptide chains are
folded and describes the overall
three-dimensional shape of the protein.
 The Z-groups in the amino-acid units are
often bulky and prevent the protein from
adopting a particular shape.
 A number of factors may play a role in
determining the overall three-dimensional
shape of a protein.

Tertiary Structure
 These include cross-links (with covalent bonds) between
the chains, ion-Ion and ion-dipole attractions and
dipole-dipole attractions, including hydrogen bonding.

Result of Structures
 As a result there is great variety in protein shapes.
 Some proteins have a flat sheet structure, others are
compact, globular shapes while others consist of long
fibrous strands.

Digestion of Proteins
 During digestion, the proteins in food
are broken down by enzymes in the
stomach and small intestine into their
constituent amino acids.
 This is a hydrolysis reaction (similar in
type to the reaction in which
polysaccharides are broken down
during digestion) and
 is the reverse of the condensation
reaction in which the original protein
was formed.

Digestion of Proteins
 The amino acids that are produced in this
hydrolysis reaction are absorbed into the
bloodstream and eventually into the cells
which use them to manufacture proteins,
depending on the part of the body
involved.
 As the body does not store proteins, a
balanced intake of protein is required
daily.
 Unused protein is broken down in the
liver and unwanted nitrogen atoms are
eventually eliminated in the urine as urea
((NH2)2CO).

Denaturation of Proteins
 The 'denaturation' of a protein refers to any change that
destroys the biological functioning of the protein.
 As mentioned above, protein structure is crucial to the
biological functioning of proteins and changes in
conditions can disrupt protein structure and, as a
consequence, alter the biological activity

 Such changes in conditions would include:
- a change in pH
- an increased temperature
- the addition of other chemicals.

 In the denaturation process, there is an unfolding and
possibly unwinding of the protein helical structures.
 The unfolded chains intertwine and come into close
contact; as a result, large clumps of protein molecules
tend to form - this is termed 'coagulation'.

 Common examples of protein
denaturation include:
 the change in egg white when the egg
is cooked
-cooking meat
- the curdling of milk in the presence
of an acid: for example, the addition
of vinegar or lemon juice or the
presence of lactic acid which is due to
the action of bacteria as milk sours.

Enzymes
 Enzymes are biological catalysts because. they increase
the rate of chemical reactions
that occur in the body.
 Biological reactions often occur in a number of stages
with each of these stages being controlled by a specific
enzyme.

Enzymes
 Enzymes are proteins.
 Enzymes and inorganic catalysts are thought to be
similar in that they accelerate the rate of chemical
reactions by lowering the 'Activation Energy' barrier for
the reaction
 - i.e. they provide a lower activation energy pathway
for the reaction

Difference of Inorganic
Catalysts and Enzymes
 Enzymes produce much .faster
reaction rates.
 Enzymes operate under much milder
conditions - lower temperatures (body
temperature compared with the high
industrial temperatures) and a narrow
temperature range.
 Enzymes are very selective in their
catalytic function.

Selectivity of Enzymes
 It is not unusual to find an inorganic
catalyst being effective for a number of
reactions.
 An enzyme, on the other hand, is an
effective catalyst for a specific reaction.
 The specificity of enzymes is
demonstrated, for example, by the
digestion of starch but not cellulose in
the human body.
 Both of these are polysaccharides but the
body does not contain the necessary
enzyme to break down the cellulose
polymer.

Harsh Deep Mishra
harshdeepmishra@gmail.com
www.angelsandachef.com
Hand phone - +91 75688 18304
Whatsapp – +91 97997 57159
Thank you,

Nutrients in food-AAAC

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Nutrients in food-AAAC

Similar to Nutrients in food-AAAC (20)

More from Angels And A Chef

More from Angels And A Chef (7)

Recently uploaded

Recently uploaded (13)

Nutrients in food-AAAC