Food technology

1. Acidulants
• Acidulants are additives that give a sharp taste to foods. They also
assist
in the setting of gels and to act as preservatives.
• The pH of a food is a measure of its acidity, alkalinity or neutrality.
Living tissues contain solutions called buffers which help to keep a
constant pH inside cells.
• many natural foods are acidic. For example, oranges, lemons, apples,
tomatoes, cheese and yoghurt contain natural acids, such as citric
acid, that
give them their characteristically sharp taste.

2. FUNCTIONS
• • Enhance quality
• • Palatability: flavor and tartness
• • Nutritive value
• • Sensory appeal: modify and smooth out the sensory qualities
• • • Prevent browning reaction
•

3. • • Antimicrobial agents
• • Buffering agents
• • Stabilize food color
• • Reduce turbidity
• • Modify melt characteristics
• • Enhance gelling
• • Leavening agents
• • Emulsifiers
•

4. • 84 Acidulants
• Acetic Acid
• Citric Acid
• Phosphoric Acid
• Adipic Acid
• Tartaric Acid
• Tricalcium citrate

5. Phosphoric Acid (E338)
• FUNCTION :
• Used as a PH control
• Used to produce alkaline pH necessary for optimum dispersion
• Important food ingredient in the preparation of pasteurized process
cheese

6. Acetic Acid (E260
• Used as a preservative
• 1. Sterilizing Acid
• Prevent /retard growth of microorganism by reducing pH
• 2. Anti-browning agent
• Inhibit oxidation reactions which lead to enzymatic and non-enzymatic browning reactions
• Tricalcium Citrate (E333iii)
• 2. Antioxidant Synergist
• Used as a chelating agent & antioxidant synergist
• 1. Chelating Agent
• Useful in retarding enzymatic browning of fruits and vegetables Used as synergists when
combined with antioxidants (e.g. ascorbates, BHA, BHT
• Partly due to the lowering of redox potential but more so on sequestering of metal ions

7. Tartaric Acid (E334)
• Used as a flavouring agent
• Most water-soluble of the solid acidulants
• Has a strong tart taste
• Add the tartness required to balance the excessive sweetness in
products
• Ability to augment flavour of fruits
• Commonly used in grape- and lime-flavoured beverages
• Manufactured from the waste products of wine industry

8. • COMMONLY USED ACIDULANTS
• • Phosphoric acid and phosphates
• • Hydrochloric acid
• • Sulfuric acid
• • Acetic acid and its salts
• • Propionic acid and its salts
• • Lactic acid and its derivatives
• • Fumaric acid and its salts
• • Malic acid and malic anhydride
• • Tartaric acid and its salts

9. Functions in details
• While having a significant effect on the flavour of food products, acidulants
perform a variety of other beneficial functions.
• While having a significant effect on the flavour of food products, acidulants
perform a variety of other beneficial functions:
• Taste: The sharpness in the taste of any food is due to the presence of food
acids. All fruits have these acids in some quantity and the result is the
typical acidic taste normally associated with fruit.
• Enhance fruit flavours: Naturally occurring food acids are citric acid, malic
acid and tartaric acid. They are also called wholesome acids. They are
found in oranges, grapefruits, pineapples, apples, peaches and other
seeded fruits. Tartaric acid is found in grapes, pineapples and potatoes.
Without the presence of these acids, fruits may taste bland.

10. • Antimicrobial effect: Some acids, such as acetic acid and lactic acid,
have an anti-microbial effect and are the basis for preservation by
fermentation in products such as sauerkraut and pickles.
• Reduce spoilage: The use of acids to reduce pH retards the growth of
many spoilage organisms, especially bacteria, and also increases the
effectiveness of food preservatives such as benzoates, sorbates and
propionates.
• Prevents discolouration: Acidification also retards the action of many
natural enzymes that are involved in the discolouration of cut fruit
and vegetables, and increases the effectiveness of natural and added
antioxidants.

11. • pH Control: Acids are also used for pH control, particularly when the
pH needs to be controlled to obtain the best gel strength in products
such as pectin jellies and jams.
• Buffering: Some products, particularly diet beverages, require some
buffering to improve flavour. The addition of a small amount of ADM
Sodium Citrate can often enhance flavour

12. Applications
• Citric acid is the dominant acid in orange juice, lemons and limes. It exists
in either anhydrous or monohydrate forms. Typically it is sold as a powder
or as a fine granular crystal.
• Anhydrous citric acid is very soluble in water and has a pH of 2.3 for a 1%
solution. It is relatively hygroscopic and has a strong acid tart flavour. It is
used as an acidulant in fruit drinks and carbonated beverages at 0.25 to
0.4%. It is often used in combination with antioxidants in the processing of
fresh frozen fruits to prevent discolouration.
• Adipic acid is characterised by being a stable powder and is slightly soluble
in water. It has a pH of 2.86 at 0.6% and is used in powdered drinks,
beverages, gelatine desserts and vegetables. It can also be used as a
leavening acidulant in baking powder and as a buffering agent to maintain
acidity within a pH range of 2.5 to 3.0.

13. Buffers
• Buffers in Food
• Buffers are chemicals that maintain the acidity of the food at the
appropriate level. This allows flavor and appearance to be maintained and
is also critical to the preservation of a number of processed foods. The
acidity of food is a measure of the concentration of hydrogen ions within
the food product. Additives that act as buffers usually comprise metal salts
corresponding to a weak acid found naturally within the food to be
preserved. For example, the addition of sodium citrate to a food containing
citric acid will create a buffer solution. In the buffer solution, the weak acid
and its salt exist in equilibrium, and this allows them to resist changes in
acidity by reacting with any extra hydrogen ions to remove them, or by
generating new hydrogen ions when needed. This maintains a constant
acidity within the food product.

14. • Monopotassium Phosphate
• Monopotassium phosphate (E340) is principally used as an antioxidant, but
it also has buffering capabilities. It is used in pudding products such as
custard and milk powder and jelly mixes, and may be added to cooked
meat. Monopotassium phosphate is an important ingredient in many
sports drinks, as it provides potassium as an electrolyte, as well as offering
a buffering action.
• Potassium Tartrate
• Potassium tartrate (E336) is obtained from grapes during the wine-making
process. In addition to its buffering action, potassium tartrate also helps
bread to rise consistently. It is used as a buffer in wine and bread
production, and may also be added to fruit pie mixes.

15. • Food Uses
• Sodium alginate is used to thicken foods and as a preservative
emulsifier to help bind processed foods together. It is usually used in
food that has a thick or jelly like consistency, such as canned fruit,
puddings and even processed meat.
• Corn or maize starch may be used as a substitute to thicken the
product, but it may change the consistency of the final product.

16. In Food Industry
• Buffers are used in foods to maintain the acidity of the food in order to
preserve the flavor and appearance of food.
• These additives usually are weak acids or their respective salts already
naturally present in some foods.
• Potassium Citrate is a antioxidant and buffering agent that is found in a
number of food products like cheese, jam, biscuits etc.
• Calcium Citrate is an important acidity regulator that is often used in
carbonated drinks.
• Sodium Citrate is used principally in James and jellies. They are added to
food containing citric acid which creates the buffering solution. The weak
acid and its salt exist in equilibrium and allows them to resist change in
acidity by generating the H+ or reacting with the H+ and maintaining the
pH.

17. Sweetners
• SWEETNERS
• • Sweetening agents are the substances which are added to a drug
formulation to mask its bitter taste.
• • Sugar is the most widely used natural sweetening agents.
• • It imparts viscosity to drug and also even act as preservative for liquid
dosage form.
• • Sugar having lot of disadvantages like dental caries, high blood sugar,
calories etc
• . • Among this there are various substitute available over sugar
• . • There are 2 types of substitute which are used as sweeteners, 1) Natural
sweeteners 2) Artificial sweeteners

18. • CLASSIFICATION OF SWEETNERES
• •The sweeteners are classified on their nutritive values
• A. Nutritive Sweeteners
• B. Non Nutritive sweeteners
• NUTRITIVE SWEETNERES
• • Alternative nutritive sweeteners are sugar alcohol such as Sorbitol,
Mannitol, Lacitol etc
• . • It having properties like less sweet and less calories
• • FRUCTOSE- 4Kcal/gm the same as sucrose and it doesn't cause
fluctuation in blood sugar, thus better choice for diabetic patients.
• • 1.5 times sweeter than sugar and cost effective for food industry.

19. • NON NUTRITIVE SWEETNERES
• • Examples include Aspartame, Saccahrin, Clycamate, Alitame etc.
• • More sweeter and thus only small quantity is required for
sweetening food preparation.
• • It is the artificial sweeteners.

20. • SWEETNERS FROM NATURAL ORIGIN
• •Stevioside
• •Glycyrrhizin
• •Neohesperidin Dihydrochalcone
• •Thaumatin
• •Monellins

21. • STEVIOSIDE AND REBAUDIOSIDE
• • Biological Source: It is extracted from a South American plant Stevia
rebaudiana Berrtoni
• • Family: Compositae
• • Characteristics: 1. The dried leaves of the plant, the water extract of the
leaves and the purified ingredients of extract are used as sweetening
agents.
• 2. It’s tainted with a bitter and undesirable after taste.
• 3. No side effects.
• 4. Both are diterpene Glycosides.
•

22. • DISADVANTAGE
• •Steviol has been reported to be mutagenic.

23. Glycyrrhizin
• : B.S.: It is a mixed Ca & K salt of Glycyrrhizic acid found in Glycyrrhiza
glabra
• (Family: Leguminosae) Characteristics:
• 1. 50x – 100x >> Sucrose, Ammonium Glycyrrhizine is 50x sweetner than
sucrose and its salt are characterized by a delayed sweeter onset.
• 2. Chemical constituents: Glycyrrhizic acid is a triterpenic glycoside of Beta-
Amyrin type which contain two Beta-1,2 Glycoside linked Glucoronic acid.
• Uses: As flavoring agent & as flavor enhancing effect in food products.
Disadvantages: Causes Oedema and Hypertension. So its dose should be
200 mg per day or less

24. • Honey
• • A natural sugar made by bees from flower nectar contains Fructose
& Glucose & tiny amounts of healthy antioxidants
• • 21 calories per teaspoon
• • 1-1.5x sweeter than sugar, so you can use less
• • Processing: Minimal
• • Health effects - Infants can contract botulism from honey

25. • 1. GENERAL NAME: Ca Saccharin,Na Saccharin
• 2. MOLECULAR FORMULA: C7H5NO3S
• 3. CODE NO. E954
• 4. IUPAC NAME: 1,2 benzisothiazol-3(2H)- one-1,1-dioxide Na & Ca
Salt.
• TECHNOLOGICAL PROPERTIES:
• 1. Very Stable under almost all food processing conditions
• . 2. Have a Long Shelf Life
• . 3. Non Caloric Sweetner.

26. • APPLICATIONS:
• 1. Utilized in most Drugs, Dietary products & Cosmetics.
• 2. Have slight to moderate Metallic or Bitter after taste.
• 3. This aftertaste can be masked by the Use of Lactose or Combining
Saccharin with Aspartame or other Sweetener.
• 4. When combined it has Synergistic Effect on Sweetness thereby
reduced the Total Amount of Non Caloric Sweeteners.

27. • PRODUCT MAX PERMITTED LEVELS (ppm) 1 Soft drinks 100
• 2 Pan masala 8000
• 3 Traditional sweets 500
• 4 Chocolate 500
• 5 Sugar based/sugar free confectionery 3000
• 6 Chewing gum/bubble gum 3000 ACCEPTABLE DAILY INTAKE (ADI) OF
SACCHARIN = 2.5mg/kg BODY WEIGHT.
• By (FSSAI/JOINT FAO/WHO) FSSA

28. ASPARTAME
• 1. IUPAC NAME: Methyl L-aspartyl-L- phenylalaninate.
• 2. MOLECULAR FORMULA: C14H18N2O5
• 3. CODE NO. E951

29. • PRODUCT:
• 1. Odorless White Crystalline Powder.
• 2. Clean, Sweet Taste.
• 3. Slightly Soluble in Water.
• 4. Sparingly Soluble in Alcohol.
• 5. 150-200 times sweeter than Sucrose
• 6. Provides 4kcal/g.
• 7. COMMON BRAND NAME: Equal

30. • APPLICATIONS:
• 1. Best used in chewing gum, instant coffee and tea.
• 2. Also used for sweetening most soft drinks, dairy products such as
yoghurt and ice cream and dessert mixes. (Homler, 1994)
• 3. Soft drink manufacturers often increase the stability of aspartame
by raising the product pH slightly and controlling inventory.
• 4. Usually the mixture of saccharin- aspartame further increase the
stability.

31. • PRODUCT MAX PERMITTED LEVELS (ppm)
• 1 Soft drinks 700
• 2 Biscuits, bread, cakes and pastries 2200
• 3 Traditional sweets 200
• 4 Chocolate 2000
• 5 Sugar based/sugar free confectionery 10000
• 6 Chewing gum/bubble gum 10000
• 7 Jam, jellies and marmalades 1000
• 8 Ice cream, frozen dessert and pudding 1000
• 9 Yoghurt 600
• 10 Ready to serve tea/coffee based beverages 600 FSSAIACCEPTABLE DAILY INTAKE (ADI)
OF ASPARTAME = 40 mg/kg BODY WEIGHT. (FSSAI/JOINT FAO/WHO)

32. • TECHNOLOGICAL PROPERTIES:
• 1. Stability in Dry Products is Good.
• 2. It enhance food flavours.
• 3. Not suitable for all foods or food processes. (Stegnik and Filer,
1984)
• 4. Loss of sweetness is observed in foods that have low pH or in foods
heated for long periods.
• 5. Excessive storage time causes 40% loss in aspartame concentration
which reduces the sweetness.

33. Sequestrant
• A sequestrants is a food additive whose role is to improve the quality and stability
of the food products. Sequestrants form chelate complexes with polyvalent metal
ions, especially copper, iron, and nickel, which serve as catalysts in the oxidation
of the fats in the food. Sequestrants are a kind of preservative.
• Common sequestrants
• 1. Calcium disodium ethylene diamine tetra-acetate (E385)
Sodium and calcium salts of EDTA are commonly used in many foods and
beverage
• 2. Glucono delta- lactone (E575)
• Glucono delta-lactone (GDL) E575a is a naturally-occurring food additive used as
a sequestrant, an acidifier, or a curing, pickling, or leavening agent. 3. Sodium
gluconate (E576)
• 4. Potassium gluconate (E577)

34. • Sequestering agents according to PFA Rule 70, are substances which
prevent adverse effects of metals catalyzing the oxidative break down
of foods forming chelates thus inhibiting discoloration, off taste and
rancidity which remain active in alkali solutions.
• Recommended usage levels for citric acid typically vary between 0.1
& 0.3% with appropriate antioxidant at levels ranging between
100ppm & 200ppm

35. • 5. Sodium tripolyphosphate
• 6. Sodium hexamataphosphate (E452i)
• Sodium hexametaphosphate (SHMP) is a hexamer of composition
(NaPO3)6. Sodium hexametaphosphate of commerce is typically a
mixture of polymeric metaphosphates, of which the hexamer is one,
and is usually the compound referred to by this name. It is more
correctly termed sodium polymetaphosphate. SHMP is used as
a sequestrant and has applications with in a wide variety of
industries, including as a food additive in which it is used under the E
number E452i .

36. • 7. Sodium tripolyphosphate
• It is prepared by heating a stoichiometric mixture of disodium
phosphate, Na2HPO4 and monosodium phosphate, NaH2PO4 under
carefully controlled conditions.
• 2Na2HPO4 + NaH2PO4 → Na5P3O10 + 2H2O
• It is used in various applications such as a preservative for seafood,
meats, poultry and pet foods. In foods, STPP is used to retain
moisture. Many governments regulate the quantities allowed in
foods, as it can substantially increase the sale weight of seafood in
particular.

37. Humectants
• Various additives employed for lowering the water activity of foods
are known as humectants.
• Some of the most commonly used humectants are:
• Glycerol
• Propylene glycol
• Sodium chloride
• Polyhydric alcohols (e.g. sorbitol)
• Sugars (e.g. sucrose, dextrose, corn syrup etc)
• The humectants are generally low molecular weight compounds,
which are easily soluble in water.

38. • These are chemically inert and do not modify the normal sensory
qualities of the product.
• Besides, these compounds are edible in large quantities without any
adverse effect.
• In addition to humectants, use of antimycotic agents f like potassium
sorbate, sodium benzoate, propylene glycol etc. is a must in the semi-
moist meats because 0.6 to 0.85 water activity ranges specifically
permits the growth of moulds.

39. Unintentional Additives
• The unintentional incorporation of chemicals into food is as
widespread as intentional addition and may present health hazards.
The sources of contamination are radioactive fall-out, thousands of
chemicals used in agricultural production, animal food additives, and
accidental contaminants during food processing.

40. Agricultural Contaminants
• Chemicals in the form of insecticides, fungicides, herbicides (in
general biocides), growth promoting substances, and pollutants etc.,
are extensively used in large numbers in agricultural production.
Without them much food would be lost. Commercial production of
some crops would be impossible if chemicals are not used. It is
estimated that 23 per cent of the commercial cabbage crop and 37
per cent of the potato crop would be lost if chemicals were not used.
Small quantities of chemical residues often remain in such crops.

41. SAFETY EVALUATION OF FOOD ADDITIVES
• Under Food additives Amendment two groups of ingredients are
exempted from regulation.
• Group I: Prior sanctioned substances that FDA or USDA has
determined safe for use in food prior to 1958 amendment.
• Eg: Sodium nitrate Potassium nitrate
• Group II: It includes GRAS, all the substances approved by experts as
safe based on their extensive history of use in food before 1958 or
based on published scientific evidence.
• Eg: Salt, sugar, MSG

42. • In 1969, president Nixon directed the FDA to update safety aspects of
all GRAS substances on the basis of current scientific investigations.
• In 1972 a committee from Federation of American societies for
experimental biology reviewed the safety of all GRAS substances on
the basis of published and other available information.
• The committee placed all reviewed substances in five categories.

43. • 1. Category I: Includes all those additives whose GRAS status was
reaffirmed. This means that the available information presented no
evidence of toxic hazards of the substance in question. These
substances are generally used according to GMP.
• 2. Category II: It includes those substances whose GRAS status was
reaffirmed at current level of use. This means that the available
information presented no evidence of toxic hazard at the level of
current use and practice.

44. • 3. Category III: Substances whose safety is reaffirmed at the level of
current use and practice.However certain uncertainties exist so that
additional studies are required.
• 4. Category IV: Include those substances for which information is
incomplete to “reaffirm safety”. This means evidence of toxicity has
been reported, however the level and manner of current use the
information is insufficient to determine the effect on public health

45. • . 5. Category V: Those substances for which no biological studies are
available to judge their safety

46. Safety of a Food Additive:
• The limit should be established with due importance to following factors:
• a. The estimated level of consumption of the food product by the consume
world for which the additive is proposed.
• b. Finding out minimum levels which would produce significant deviation
from physiological behavior.
• c. An adequate margin of safety to reduce any hazard to a minimum.
• d. Legal control over the use of food additives. This can be accomplished
only when a list of permitted additives exists with specified safe levels and
toxic levels.
•

47. • e. Stringent labeling on foods i.e., declaring the usage of additives in
food and their quantities.
• f. Employing trained food inspectors, food control laboratories and
reliable analytical methods are of utmost important for regulation /
control over usage of food additives.

50. Factors that affect toxicity or safety of
toxicants:
• Exogenous factors:
• *Nature of the compound: It depends on chemical structure and toxicity.
Eg: Ethanol CH3CH2OH 13.7 g/kg(ADI) 1,2- Ethane diol HOCH2CH2OH
6.1g/kg
• Dose of the compound
• Frequency of exposure
• Route of exposure
• Dietary factors: May delay or enhance or prevents absorption.
• Endogenous factors:
• Binding of toxicants to plasma proteins and tissues.
• Excretory process : It is of two types

51. • 1. Urinary excretion
• 2. Biliary excretion Dosage:
• i) LD(50) : Lethal Dose (50) is used to “characterize the toxic potency of a
compound”. This is defined as that dose which produces a 50% mortality in
a given test population. It is also used to indicate the magnitude of the
toxicity. Toxicity of a compound can also be used to expressed in terms of
TD50 (Tumor dose50).
• ii) Virtually safe Dose: This is the exposure level which will produce only
one tumor is 100 million persons.
• iii)No Effect Dose: It shows safety of a compound. But identifying NED is
quite difficult as most of the toxicants or chemicals often used show
latency in human for even years

52. • CLASSIFICATION: • There are three principal types of flavorings used in foods,
under definitions agreed in the E.U. and Australia.
• TYPES DESCRIPTION
• 1. Natural flavoring substances Substances which are extracted from vegetable
or animal materials and are not further chemically modified or changed. An
example is vanilla extract.
• 2. Nature-identical flavoring substances Substances that are chemically identical
to natural substances, but which are obtained by chemical processes or by
chemical modification of other natural substances. An example is vanillin, which
is identical to the vanillin in vanilla, but not obtained from vanilla pods.
• 3. Artificial flavoring substances Substances obtained by chemical synthesis or
chemical modification of natural substances, but which are not present in natural
products.

53. • more flavour categories:
• • Process flavourings are substances that are formed from natural
substances upon processing, mainly heating. A common example is
caramel, which is produced by heating sugars.
• • A smoke flavouring means a smoke extract used in traditional
foodstuffs smoking processes. These are obtained by collecting the
smoke into a fluid, which can be applied in a different production
process.

54. • Certain organic and inorganic acids can be used to enhance sour
tastes, but like salt and sugar these are usually not considered and
regulated as flavorants under law.

55. Solvent Extraction
• . • Organic solvent extraction is the most common and most economically
important technique.
• • Raw materials are submerged and agitated in a solvent that can dissolve
the desired aromatic compounds.
• • Commonly used solvents for maceration/solvent extraction include
hexane and dimethyl ether.
• • In organic solvent extraction, aromatic compounds as well as other
hydrophobic soluble substances such as wax and pigments are also
obtained.
• • The extract is then subjected to vacuum processing, which removes the
solvent for re-use (or) The solvent is then removed by a lower temperature
distillation process and reclaimed for re-use.

56. DISTILLATION PROCESS
• • The technique is based on the fact that many substances have
different boiling points.
• • During distillation, liquid mixtures are separated by heating.
• • The distillation process sees the plant or animal source material
being brought to a certain, pre-determined boiling point.
• • The steam is collected by cooling.
• • In flavouring production generally in industries it is used to produce
natural citral from lemon grass oil.

57. DISTILLATION TECHNIQUE
• : steam Distillation
• • This is one of the simple techniques for concentration of essential
oils before molecular distillation.
• • The raw material or crude oil is heated under vacuum at precisely
controlled temperatures, turning the components into vapour, which
is then cooled and condensed to a purified liquid product.

61. SENSORY EVALUATION
Sensory evaluation is a scientific discipline that analyses and measures
human responses to the composition and nature of foods and drink.
 Sensory evaluation does not just deal with "likes and dislikes,“ “OK or not
OK” but the process scientifically elicits, measures, analyses and
interprets psychological and / or physiological responses to physical
stimuli produced by a food product.
DEFINITION: ‘A scientific discipline used to evoke, measure, analyze and
interpret reactions to those characteristics of food and materials as they
are perceived by senses of sight, smell, taste, touch and hearing. ’

62. HUMAN SENSES
‘Sense’ may be described as the physiological perception of a stimuli.
There are 5 senses in human beings:
 Sight : Ability of the eye and brain to detect electromagnetic waves within the visible range
of light and interpret the image.
 Hearing : Sense of sound. When vibrations propagating through a medium (e.g. air) are
detected by the brain, sound is perceived.
 Touch : Sense of pressure perception, mostly in the skin / tongue.
 Taste
 Smell

63. HUMAN SENSES
TASTE / GUSTATION: This is a "chemical" sense. The receptors
(buds) in the tongue can distinguish 5 tastes:
 Sweet
 Salt
 Sour
 Bitter
 Umami : a savoury and subtle taste that is associated with a
soupy or brothy note. The receptors on the tongue identify the
glutamic acid residues in the food.

64. TASTE SYSTEM
• The tongue is the main taste receptor.
• The structures that give the tongue its rough structure with
raised protrusions on the surface are called papillae. Four types of
papillae present in the human tongue:
Fungiform papillae
 Fili form papillae
 Foliate papillae
 Circumvallate papillae
• Taste buds are located in all the papillae except for the Filiform
papillae.
• Tongue contains approximately 10,000 taste buds.

65. TASTE SYSTEM
TONGUE SURFACE WITH PAPILLAE
 Each taste bud has taste cells that extend into the
taste pore.
 Every taste cell is associated with one or more
nerve fibres.
 when chemicals from food contact the tips of
taste cells, Ion movement across the membrane of
taste cells takes place to cause transduction.
 These signals reach the spinal cord through many
pathways and then go to the Thalamus.
 The brain detects the taste of the food. Taste is
expressed in terms of a food being

66. SMELL / ODOUR
 The nose detects volatile aromas released from food. A specific odour may be described for
a particular food, e.g. green, cheesy, nutty etc. The intensity can also be recorded.
 Odour and taste of a food together produce the flavour of a food. Due to this mechanism,
people suffering from cold find it difficult to determine the flavours in foods.
 Usually odours are described as
aromatic pungent spicy woody floral bland green citrus like earthy rancid savoury
leathery rotten tart oily creamy acrid strong mild buttery musty weak scented
mossy fragrant

67. SCIENCE OF SMELL : OLFACTION
We humans are microsmatic : we do not possess a keen sense of smell
as it is not crucial for our survival.
 Humans can discriminate among 100,000 odors but they cannot label
them accurately.
 First, odor molecules from food bind to receptors in the nose.
 Signals from the receptors travel up to the olfactory bulb, a Qtip-like
structure roughly above the eyes. From there, some signals go to the
primary olfactory cortex and on to the higher-order parts of the brain.
 But few signals from the olfactory bulb directly go to the amygdala in
the brain, an area that is relevant to emotions and some go to the
hippocampus, which is involved in memory.
 Hence, we sometimes associate few smells in our memory with a
specific emotion.

68. SCIENCE OF SMELL : OLFACTION
THE OLFACTORY
SYSTEM
 Recognition of smell is
immediate as the olfactory
response is immediate,
extending directly to the
brain.
 This is the only place where
our central nervous system is
directly exposed to the
environment

69. SENSORY EVALUATION : NEED
• To detect the similarities /differences in a group of food products.
• To evaluate an existing food product against benchmark sample.
• To analyze food samples for further improvements based on market feed back.
• To elicit specific response to a food sample: whether acceptable or not by consumers.
• To study a particular property in an ingredient or a food product.
• To evaluate if a ready food product meets its original specification / standard sample.
• To obtain feedback data in order to make decisions and carry out suitable modification in a
food product.

70. SENSORY EVALUATION : USES
• New Product development
• Before a new product promotion
• Determine the effect of formulation changes especially when
availability of natural ingredients is scarce.
• Study the impact of processing changes.
• Ensure batch consistency.
• Monitor shelf-life changes.
• Determine consumer acceptance
• Expert versus consumer sensory report
• Sensory quality control and consumer loyalty
• Sensory evaluation in Food Science courses

71. SENSORY EVALUATION : plan
 Define the overall project objective
 Define the test objective.
 Screening the samples.
• Selection of the test method and panel.
 Conducting the test.
 Analyzing the data
 Reporting the results.
 Corrective action , if required.

72. SENSORY EVALUATION : REQUIREMENT
• Sophisticated Sensory booths as per ASTM standards with controlled temperature (20C –
22´C) and RH at 40±5%.
• Suitable Lighting in booths : White or Masked.
• Utensils / glass wares suitable for different foods.
• Laboratory for physical, chemical analysis of raw and prepared foods.
• Suitable area for preparation of food samples for evaluation.
• Suitable coding of samples : usually 3 digit coding is done.
• Appropriate method of sample presentation.
• Sensory panel members suitable for evaluation.
• Specialized software for statistical evaluation of sensory data.

73. SENSORY ANALYSIS BOOTHS

74. SELECTION OF PANEL MEMBERS
• American Society for Testing and Materials, Committee E-18 has
given the guidelines for selection & training of sensory panel
members.
• The selection of candidates should be based on specific personal
attributes and potential capability in performing specific sensory
tasks.
• Must be able to perform and repeat the task with consistent
results.
• Panel members must be free from taste / odor perception
disorders, color blindness, denture defects, frequent allergies not
be consuming medications that affect sensory functions.

75. SENSORY PANEL MEMBERS
•Panel members must have
motivation, interest and
responsible attitude towards
sensory evaluation.
•Panel members may be trained or
randomly selected based on the
type of evaluation required.

76. SENSORY METHODS
Types of tests
DESCRIMINATIVE
DESCRIPTIVE
HEDONIC
PREFERENCE
• Product oriented – analytical & objective •
Quality / quantity of a trait • Likeness /
difference in samples • For Standardization
purposes • Few selected trained panel members
o People oriented – affective & subjective •
Acceptance of a product • Initial impressions
important • Personal reactions / likes matter
• Usually more panel members eg. Samples
tasted by people visiting a booth in a
crowded mall. 20

77. DISCRIMINATORY TESTS
• Discriminatory tests are done to
– determine whether the two samples are perceptibly different.
– When 2 samples are chemically different and may be perceived as
identical.
– When there is a change in the processing method of a food
product.
• Discriminatory tests are extremely useful for evaluation of a ‘new,
improved ‘ version of an already existing product.

78. HEDONIC TEST
• Very useful for measuring food acceptability.
• Uses a 9- point Hedonic scale ranging from ‘extremely dislike’ to
‘extremely like’.
• It is a people oriented test with large number of panel members,
usually 50 and above.
• An extension of Hedonic scale with nine “child friendly”
expressions ranging from “super good” to “super bad” is used with
5-10 year old children.
• A scale having “smiley” faces also elicits good response for food
acceptability from children.

79. HEDONIC SCALE
• The 9-Point Hedonic Scale Point
• Like Extremely 9
• Like Very Much 8
• Like Moderately 7
• Like Slightly 6
• Neither Like nor Dislike 5
• Dislike Slightly 4
• Dislike Moderately 3
• Dislike Very Much 2
• Dislike Extremely 1

80. TRIANGLE TEST
• Panelist is presented with one different and two alike samples. If possible, all three samples
should be presented to the panelist at once, and the panelist should be instructed to taste
the samples from left to right. The six possible order combinations should be randomized
across panelists. For samples A and B, the six possible order combinations are: AAB, ABA,
BAA, BBA, BAB, and ABB. The panelist is instructed to identify the odd sample and record his
answer

81. TRIANGLE TEST
You are given three coded PRODUCT samples out of which two are
identical and one is different. Please encircle the code of the
sample found different.
o Indicate the degree of difference between the ‘’ídentical’ and
‘’different’ samples:
Very less ----------
Significant ----------
Much ----------
Very high ----------
Please tick the acceptable sample:
Identical samples ---------
Different sample ---------

82. DUO – TRIO TEST
 A Reference is provided with 2 coded samples. • Is useful for products that have relatively
intense taste, odor, and/or kinesthetic effects.
• A Duo-Trio Test determines whether or not a sensory difference exists between two samples.
The degree / intensity of difference is not elicited . This method is particularly useful:
• To determine whether product differences result from a change in ingredients, processing,
packaging, or storage
• To determine whether an overall difference exists, where no specific attributes can be
identified as having been affected.

83. DUO – TRIO TEST
You are given one Control sample of PRODUCT labelled as ‘R’.
Along with that there are two coded test samples out of which
one is identical with ‘R’ and the other is different. Tick the sample
found different.
 Sample code 619 _____
352 _____
 Comments:
Name:
Date:

84. PAIRED COMPARISON TEST
• The paired-comparison test (UNI EN ISO 5495) determines whether two products differ in a
specified attribute, such as sweetness, crispness, redness, etc.
• Two differently coded samples are presented to each panelist simultaneously . (30 & more
members)
• The panelist chooses the one that is perceived as more intense in the specified sensory
attribute.
• The paired comparison implicates the “forced” choice and therefore the judges must give
an answer in any case.
• The chance probability associated with this test is 1/2.
• Frequently used in Preference tests.

85. PAIRED COMPARISON TEST
Start with the coded sample on your left.
Tick the sample that is more Better than others.
 AB ---------
 BA ---------
Comments: Name:
Date: