M.pharm 1 semester notes

1. FOOD ANALYSIS

3.  Carbohydrates are broadly defined as polyhydroxy aldehydes
or ketones and their derivatives or as substances that yields
one of the compound .
 Composed of carbon, hydrogen, and oxygen.
 Carbohydrates include sugars, starches, cellulose, and
glycogen.
 Carbohydrates serves as a primary source of energy and
needed for storage and liberation of energy.
 Carbohydrates are the most abundant organic compounds in
the plant world.

4.  They are used as material for energy storage and production.
 They exert a protein-saving action
 Their presence is necessary for the normal lipid metabolism.
 Glucose is indispensable for the maintenance of the integrity of
nervous tissue
 Two sugars, ribose and deoxyribose, are part of the bearing
structure, respectively of the RNA and DNA and obviously find
themselves in the nucleotide structure as well.
 They take part in detoxifying processes

5. CLASSIFICATION

7.  Single sugar unit = monosaccharide
ex: glucose = primary animal energy source
 Two sugar units = disaccharide
ex: lactose = milk sugar
 5 units or more = oligosaccharide or
polysaccharide
ex: amylose = starch

8.  Monosaccharides are water-soluble crystalline compounds.
 They are aliphatic aldehydes or ketones which contain one
carbonyl group and one or more hydroxyl groups.
 Most natural monosacharides have either five (pentose) or six
(hexoses) carbon atoms. Commonly occurring hexoses in
foods are glucose, fructose and galactose , which commonly
occurring pentose are arabinose and xylose.
 The reactive centers of monosaccharides are the carbonyl and
hydroxyl groups.

9.  Oligosaccharides are formed by short chains of
monosaccharidic units (from 2 to 20) linked one to the next
by chemical bounds, called glycosidic bounds.
 The most abundant oligosaccharides are disaccharides,
formed by two monosaccharides, and especially in the human
diet the most important are sucrose (common table
sugar), lactose and maltose.
 Within cells many oligosaccharides formed by three or more
units do not find themselves as free molecules but linked to
other ones, lipids or proteins, to form glyco conjugates.

10.  Polysaccharides are polymers consisting of 20 to
107 monosaccharide units.
 They differ each other for the monosaccharides recurring in
the structure, for the length and the degree of branching of
chains or for the type of links between units.
 Whereas in the plant kingdom several types of
polysaccharides are present, in vertebrates there are only a
small number

12.  The word hygroscopic means water attracting.
 Sugar absorbs moisture from air ,when it is exposed to air
and are known to be very hygroscopic in nature ,hence sugar
should be stored in airtight container.
 Sugar tend to absorb moisture and sticky when exposed to
air.
2. SOLUBILITY
 Sugar are soluble carbohydrates.
 The solubility decreases as the sugars come together ,as
often happens in sugar powders or granulates.
 The sugar arranged in descending order of solubility are
fructose , sucrose, glucose, maltose and lactose.
 This property is important to obtain a particular product
when mixture of sugar is used.

13.  The ability of sugar to dissolve and reform crystals.
 Sugar is dissolved in a liquid and heated, the liquid
evaporates, concentrating the sugar solution .
 As the solution cools ,the sugar re-form into crystals.
 Crystals of sugar thus obtained are very desirable in sugar
coated preparations like sugar coated nuts and other such as
icings and candies.
 Crystallization depends upon a number of factors include,
nature of the crystallizing medium, concentration of sugar in
the preparation, temperature ,addition of other ingredients ,
such as butter, ghee, egg etc.

14.  When starch is mixed with water and heated the starch
granules swell and eventually rupture, absorbing liquid
which thickens the mixture. On cooling, if enough starch is
used, a gel forms.
 Gelatinization can take place in different temperature
range, commonly it take place at 88⁰C – 90⁰C.
Common thickening agents : plain wheat flour, corn flour
etc.
 Two factors affect the qualities of the gel produced. These
are the ratio of amylose to amylopectin and the method used
to prepare the food.

15.  Gelation is the method of solidification mainly
through freezing is the creation of gel or the
solidification of any gelation solution.
 The gelatin is used for gelation. The gelatin liquid
form a thick sugar solution and constantly thickens
when freezed.
 There is no any definite setting point.
 In some food gel is produced on cooling and in
some it may be formed on heating.
 Gels can either be thermo-irreversible or thermo
reversible, it all depends on the type of gelation
occurred.
 EXAMPLE: cooling- gelation in gelatin, heating-
egg white.

16.  Viscosity is a fluid’s resistance to flow or fluid thickness. The
thicker the liquid, more is its viscosity.
 The viscosity of a fluid can be measured by
1. Seeing how far a fluid can flow down an incline.
2. Viscometer- measures the force necessary to move through a
liquid.
3. Household instruments- measuring how far a liquid can move
on a slight incline after a certain amount of time.
 Measuring of viscosity is to determine how resistant that
material is to following
1. Flow down a slight incline very quickly – very little
resistance to flow.

17.  2. Lot of force to move through a liquid, it has a lot of
 resistance to flow.
 • A fluid will be more resistant to flow the more internal
 friction it has.
 • Many food industries check for vicosity. There is an
 acceptable range of vicosity if it is not in the range then it
 will not be sold.

18.  Colloidal are formed when one substance is dispersed
into another, but does not combine to form a solution.
 There are many types of colloidal systems based on the
state of two substances mixed together.
 GEL,SOLUTION, FOAM AND EMULSIONS.
 Most colloidal are stable, but the two substance may
separate over a period of time because of an increase in
temperature or by physical force. Sometime will be
unstable when frozen or heated, especially if they contain
emulsion of fats and water.

19.  Sol and gel both are liquid loving colloids
 Sol- solid particles are dispersed in liquid phase
when, the mixture is heated or cooled the sol
changes to gel, which resembles solid rather than
a liquid.

20.  OIL+ WATER= EMULSION
 Emulsion is unstable. The two liquids are immiscible. A
stable emulsion is formed when two immiscible liquids are
held stable by a third substance called as an Emulsifying
agent.
 There are two type of emulsifying agent, HYDROPHILIC
(water loving) and HYDROPHOBIC ( water hating).
 Emulsion may be
1. oil-in-water(o/w) – small oil droplets in water(milk)
2. water-in-oil(w/o) – small water droplets in oil (butter)

21.  When small bubbles of gas dispersed in a liquid they form
foaming.
 EXAMPLE : egg white foam, as air bubbles get incorporated.
 If egg white is heated, protein coagulates and moisture is
driven off. This form a solid foam.

23.  Carbohydrate content can be measured after all
other components are measured
 But! This can lead to erroneous results
 Instead, Directly measure the carbohydrate content

24.  Monosaccharide and Oligosaccharides
Prior to Analysis: Sample Preparation
 Amount of preparation depends on the nature of the food
 Aqueous solutions require little preparation
 But! Physically Associated or Chemically Bound need to be
isolated
 Method of Isolation depends on the :
1. Carbohydrate type
2. Food Matrix Type
 3. Purpose of the Analysis

25. DRIED
UNDER
VACCUM
GROUD TO A
FINE
POWDER
DEFATTED
BY SOLVENT
EXTRACTOIN

26.  1. Boil a defatted sample with 80% alcohol solution
• Mono & Oligo – soluble in alcoholic solutions
• Poly & Dietary Fibers – insoluble
 2. Separate the component by filtering the boiled solution
• Filtrate and Retetnate
 3. The two fractions are dried and weighed
Note!
 • Filtrate may contain small molecules (Amino acids, Organic Acids,
Pigments, Vitamins, Minerals)
Have to be remove prior analysis by treatment of Clarifying Solutions or
Ion-Exchange Resins
 • Alcohol can be removed by evaporation under vacuum

27.  1.Chromatographic and Electrophoretic
methods
 2. Chemical methods
 3. Enzymatic methods
 4. Physical methods
 5. Immunoassays

28. Most powerful analytical techniques
Analysis of Type and Concentration of Mono and Oligo
Commonly used to separate and identify carbohydrates
 1. Thin Layer Chromatography, TLC
 2. Gas Chromatography, GC
 3. High Performance Liquid Chromatography, HPLC
Carbohydrates are separated base of their differential
absorption characteristics

29.  Carbohydrates are separated by electrophoresis after
being derivitized –make them electrically charged
 Solution of derivitized carbs is applied to a gel and a
voltage is applied across the carbohydrates are then
separated base of their size
 The smaller the size – faster it moves in an electrical
field

30. These methods are used to determine Mono & Oligo
because most of them
are reducing sugars
 Concentration of carbohydrates can be determined:
1. Gravimetrically (Gravimetric Methods)
2. Spectrophotometrically (Colorimetric Methods)
3. Titration Methods
Note!
 Non-reducing carb can be determined but they have
to be hydrolyzed

31.  They base on the ability of the enzymes to catalyze specific
reactions
 These methods are rapid, highly specific, sensitive to low
concentrations
 Little sample preparation is required
– Liquid Foods – can be tested directly
– Solid Foods – dissolved in water
 Two commonly used methods
1. Allow the reaction to complete and measure the
concentration of the product
Concentration of the product – Concentration of the Initial
Substrate
2.Measure the initial rate of the enzymes catalyzed reaction
Rate - Substrate Concentration

32.  These methods rely on being a change in
physiochemical characteristics as its carbohydrate
concentration varies
 Commonly Used
 1. Polarimetry
 2. Refractive Index
 3. Infrared
 4. Density

33.  Specific for low molecular weight carbohydrates
• Developed by
1. Attaching the carbohydrate to a protein
2. Injecting it into an animal
3. Animal develops antibodies specific for the
carbohydrate molecule
4. Antibodies are extracted and used for determining
the concentration of the
carbohydrate
 Immunoassays are extremely sensitive, specific,
easy to use, and rapid

34. Test objective
Molisch test To identify the carbohydrate from
other macromolecules lipids and
proteins
Benedict's test Benedict's reagent is used as a test for
the presence of reducing sugars.
Barfoed’s Test To distinguish between reducing
monosaccharides, reducing
disaccharides and non reducing
disaccharides.
Bial’s Test To distinguish between pentose
monosaccharide and hexose
monosaccharide
Seliwanoff's Test To distinguish between aldose and
ketone sugars

36.  Low molecular weight carbohydrates:
During wet heat treatment, as in blanching, boiling and
canning of vegetables and fruits, there is a considerable loss of
low molecular weight carbohydrates (i.e. mono- and
disaccharides) as well as micronutrients, into the processing
water.
The loss of glucose and fructose at boiling will be higher
than that of sucrose.
 Dietary fibre
No leaching of dietary fibre into the processing water has
been reported with blanching, boiling and canning of carrots,
green peas, green beans and Brussels sprouts. There was a
40% loss of dietary fibre (mainly insoluble) with boiling.

37. Maillard reactions
Non-enzymatic browning reactions (Maillard reactions)
occur between reducing sugars and amino groups in foods at
processing and in storage. These reactions are temperature
dependent and most extensive at intermediate water activities.
When a non-reducing disaccharide such as sucrose is
replaced by, for example, high fructose corn syrup containing
glucose and fructose, Maillard reactions occur much more
rapidly and extensively.
 Starch
heat-induced effects
Gelatinization refers to the irreversible loss of the
crystalline regions in starch granules that occur upon heating in
the presence of water. The temperature range during which the
crystalline structure of the starch granule is lost is dependent on
the water content, and on the type of starch.

38. Retrogradation
 Gelatinized starch is not in thermodynamic equilibrium. There
is, therefore, a progressive re-association of the starch
molecules upon ageing . This recrystallization is referred to as
retro gradation, and may reduce the digestibility of the starch
Par-boiling
 During par-boiling of rice, the kernels are subjected to a pre-
treatment involving heating and drying. This process reduces
the stickiness of the rice, possibly by allowing leached
amylose to retrograde and/or form inclusion complexes with
polar lipids on the kernel surface. Parboiling also affects the
final cooking properties of the rice.

39.  Starch
texturization
In pasta products, gluten forms a viscoelastic network that
surrounds the starch granules, which restricts swelling and
leaching during boiling.
 Dietary fibre
Milling and peeling
During milling of cereal grains to refined flours the outer
fibre-rich layers are removed, resulting in a lower content of
total dietary fibre . This reduction is due mainly to a
decrease of insoluble fibre

40.  Heat-treatment
 Processes involving heat-treatment may affect the dietary
fibre in different ways. An increased temperature leads to a
breakage of weak bonds between polysaccharide chains. Also
glycosidic linkages in the dietary fibre polysaccharides may be
broken.
 Hydration properties (swelling, water-holding and water-
binding capacity)
 Most raw materials containing cereal fibres are ground for
better acceptance of the final product and this process can
affect hydration properties. Swelling and water-binding
capacity of pea hull fibres are decreased by grinding, whereas
the water-holding capacity was slightly increased .

42.  Carbohydrates are most commonly consumed as
polysaccharides (e.g. starch, fibre or cellulose) or
disaccharides (e.g. lactose, sucrose, galactose) and therefore
need to be broken down into their simpler monosaccharide
forms which the body can utilise.
 The digestion process of polysaccharides such as starch will
begin in the mouth where it is hydrolysed by salivary amylase.
The amount of starch hydrolysed in this environment is often
quite small as most food does not stay in the mouth long.
Once the food bolus reaches the stomach the salivary
enzymes are denatured. As a result, digestion predominantly
occurs in the small intestine with pancreatic amylase
hydrolysing the starch to dextrin and maltose.
Enzymes classed as glucosidases on the brush border of the small intestine break
down the dextrin and maltase, lactase and sucrase convert the other disaccharides
into their two monosaccharide units.
Digestion

44. Absorption & transport
 The monosaccharide units, glucose, galactose and fructose
are transported through the wall of the small intestine into
the portal vein which then takes them straight to the liver.
The mode of transport varies between the three
monosaccharides and is described in brief below. Both
glucose and fructose are absorbed relatively quickly,
depending on what other nutrients are eaten at the same
time. For example a meal or food containing protein and fat
causes the sugars to be absorbed slower than when
consumed on their own.

47.  Carbohydrates are used in pharmacy:
 For the preparation of simple syrup(sucrose)
 As diluent and binders for the preparation of tablets
(lactose and starch)
 For the preparation of infants’s food (starch and
dextrin)
 For the preparation sterile I V solution (dextrose)
 In antidiarrheal drugs (pectin)
 Starch, sugar, gums& pectins are used as thickening
agents in making jams, cakes , cookies, noodles and
variety of other foods
 In food industry both fast releasing and slow
releasing carbohydrates are used.
 Adding fibrer to foods increase bulk

48.  Starch, sugar, gums& pectins are used as thickening agents in
making jams, cakes , cookies, noodles and variety of other
foods
 In food industry both fast releasing and slow releasing
carbohydrates are used.
 Adding fibrer to foods increase bulk
 Simple sugars are used as sweetening agent, consisting agent
and browning.