discussion on food faddism food standards food adulterants food contaminants food toxicity All these topics are useful for exam purpose.

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FOOD SCIENCE AND
NUTRITION
-Gokul Arora
M.Sc. Medical Biochemistry
4/13/2021

2. CONTENTS
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 Food Faddism
 Effect of preparation and processing on Nutritive Value of foods.
 Food Additives
 Food Contaminants

3. FOOD FADDISM
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 A fad, sometimes called a trend, or a craze, refers to a fashion that becomes popular in a culture quickly,
then become unpopular.
 Food faddism refers to an unusual pattern of food behavior based upon a magnified belief in the effects of
food or nutrition on health and disease.
 Food faddism is born of little awareness about basic scientific dietary facts.
 Food faddism is an important factor that cause malnutrition.
 Food quackery is the promotion for special foods, products, with false or misleading claims, usually for
personal financial gain.

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2 general forms of food faddism:
•Individual faddism which is marked by acute or chronic aberrations such as
avoidance or cravings of specific foods.
•Collective faddism which involves large groups of people and produces most
number of problems.

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Effect of preparation and
processing on nutritive value of
food

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Food is a complex mixture of many different chemical components.
The study of food preparation involves understanding the changes that occur in these components during
preparation as a result of their interaction with one another, with the medium of cooking, the temperature of
cooking and the environment.

7. METHODS OF
FOOD
PREPARATION
Choice of fuel
 The heat for cooking is usually generated by the use of
kerosene, gas, electricity, charcoal, wood or sawdust as
fuel.
Medium of food preparation
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Pan-frying or
shallow frying
Steam
Oil/fat Air (dry heat)
Boiling
Simmering
Stewing
Water
Deep fat frying
Pressure cooking
Roasting
Baking
Grilling

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Pasturization = the process of heating a food
usually a liquid to or below its boiling point
for a defined period of time.
Advantages = 1.Destroy all pathogens
2.reduce the no. of bacteria
3.inactivate enzymes
4. extend the shelf life
Demerits
Loss of Iodine ( 20%)
Loss of Vitamin C ( 0-20%)
Loss of useful enzymes
Frying = heat processing in hot
oil/fat.
Advantages-
1.Thermal destruction of micro-
organisms and enzymes
2.Increases the energy value of food
Demerits
Causes oxidation of the oil to form
volatile carbonyls, epoxy acids, etc.
Oxidation of fat-soluble vitamins.
Cooking
Advantages-
1. Food becomes easy to be
digested.
2. Destruction of pathogenic micro-
organisms.
3. Caramelisation of sugar.
4. Enhances flavor and texture of
food.
Demerits
 Loss of water soluble vtamins.
 Loss of minerals such as sodium,
selenium, etc.
 Sometimes grilling of meat
results in the formation of
carcinogens like HCA and PAH.

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Blanching
Merits
1. Peels can easily be removed
to improve digestibility.
2. Destroys enzymes that bring
about spoilage.
3. Texture can be maintained
while improving the colour
and flavour of food.
Demerits
 leaching of water-soluble
and heat sensitive nutrients.
Dehydrated Foods
-90 to 98% moisture free
Merits
1. Longer shelf life
2. More calories by weight
3. Same calorie, protein, fat
and carbohydrate content.
Demerits
 Loss of Vitamin C and
carotenoids.

10. Retention of Nutritive Value during preparation
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 Some simple rules for retaining nutritive value and flavour are given below:
1. Wash vegetables before cutting.
2. Cut vegetables just before cooking and introduce cut vegetables into boiling water, if to be cooked in water.
3. Use just enough water for cooking, if the vegetables or other foods are to be served as such.
4. Cook foods until just done and serve immediately.
5. When preparing soups, the slowest cooking ingredient should be added first, followed by addition of other
ingredients, which cook in shorter time.
6. Spices and other flavour ingredients should be added in the oil used for seasoning.
7. Vegetables, salads should be prepared just before serving.
8. Use of acid foods, such as lime juice, tomatoes, vinegar or yogurt as dressings in salads prevents loss of vitamin
C, because it is stable in acid medium.
9. Fruits are best eaten as they have been customarily eaten in tropics.

11. FOOD ADDITIVES
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 According to the Food Protection Committee of the Food and Nutrition Board, food
additives may be defined as follows:
 The National Academy of Sciences (1973) has listed the purposes of food additives as
follows:
a substance or mixture of substances, other than a basic foodstuff, which is present in a food
as a result of any aspect of production, processing, storage, or packaging. The term does not
include chance contaminants.

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CATEGORIES OF FOOD ADDITIVES

13. SORBITOL
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 CHEMISTRY
 Sorbitol is a six-carbon sugar alcohol that was originally found in the berries of mountain ash.
 Sorbitol has the same steric configuration as glucose, and it is chemically synthesized from glucose or
dextrose for commercial use.
 Sorbitol has about half the sweetness of sucrose
 TECHNOLOGICAL PROPERTIES
• Sorbitol is used mainly as a sweetening agent for dietetic foods, where it combines moderate sweetening
power, specific flavor characteristics, and pleasant viscosity in liquids.
• It is used in sugar-free candies and chewing gum and in diabetic foods.
 TOXICOLOGY
• Since sorbitol is absorbed slowly, foods sweetened with sorbitol are thought to be suitable for diabetics
provided that the calories are taken into account. However, large amounts of sorbitol can cause flatulence,
diarrhea, and abdominal distension

14. SACCHARIN
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 CHEMISTRY
 Saccharin can be produced by two methods, either from toluene and chlorosulfonic acid or from
methyl anthranilate .
 Saccharin and sodium saccharin do not occur in nature.
 TECHNOLOGICAL PROPERTIES
 Saccharin and its calcium and sodium salts are very stable under almost all food processing
conditions, and they also have a long shelf life.
 Saccharin is at present the only noncaloric sweetener that appears to be stable during cooking and
baking of food products and can be utilized in most drugs, special dietary products, and cosmetics
 TOXICOLOGY
 High doses of saccharin have been shown to cause bladder cancer in laboratory animals.

15. SULFITES
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 Sulfites are unique in their ability to perform a number of useful functions as food
additives—control of both enzymatic and non-enzymatic browning, suppression of microbial
growth, and bleaching.
 Among the products that are treated with sulfites are dehydrated fruits and vegetables,
prepeeled potatoes, fresh grapes, and wine.
 Treatment conditions vary widely. Sulfite may be applied as sulfur dioxide; sulfurous acid; or
sodium (or potassium) sulfite, bisulfite, or metabisulfite.
 SIDE EFFECTS
 Sulfite residues in foods have been responsible for some severe allergic reactions in
susceptible individuals, usually asthmatics. Fatal anaphylactic reactions have also been
reported.

16. TARTRAZINE
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 Tartrazine, also known as FD&C Yellow #5, is an approved artificial food color.
 This colorant has been widely used in foods and pharmaceuticals for many years
SIDE EFFECTS
 Tartrazine is a color additive that is associated with adverse reactions (asthma and
chronic hives) in a sensitive subpopulation of consumers.

17. OLESTRA
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 Olestra received food additive approval more recently and can be used as a fat
replacer.
 Because Olestra is poorly absorbed and is not metabolized, it does not provide the
calories that would be obtained with fat in similar products.
SIDE EFFECTS
 However, the use of Olestra has been associated with acute gastrointestinal
complaints, including anal leakage

18. NUTRITIONALADDITIVES
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 The term nutritional additives can be used to mean the addition of vitamins,
minerals, amino acids, fatty acids, as well as other pure chemical compounds to food
in order to improve or maintain the nutritional quality of foods.
 Nutritional additives can be used to restore nutrients to levels found in the food
before storage, packaging, handling, and processing.
 Another use of nutritional additives is to improve the nutritional status or correct
nutritional inferiority in a food that replaces a more traditional nutritional food, an
example would be the fortification of breakfast drink substitutes with folacin and
vitamin C.

19. SIDE EFFECTS OF NUTRITIONAL
ADDITIVES
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 Excessive consumption of the B vitamin, niacin, can cause an acute onset of flushing,
pruritus, rash, and burning or warmth in the skin especially on the face and upper trunk ; and
gastrointestinal discomfort has been noted by some patients.
 With children, signs and symptoms of acute vitamin A toxicity include anorexia, bulging
fontanelles, drowsiness, increased intracranial pressure, irritability, and vomiting.

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 Adulteration of food consists of a large number of practices:-
 Adulteration results in two disadvantages for the consumer:
 First, he is paying more money for a food stuff of lower quality
 Secondly, some forms of adulteration are injurious to health, even resulting in death, as for
example,
Mixing
Substitution
Concealing the quantity
Putting up decomposed foods for sale
Misbranding or giving false labels
Addition of toxicants
Adulteration of mustard oil with argemone oil causing epidemic dropsy or adulteration of edible oils with trycresyn
phosphate (TCP) resulting in paralysis and death

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Common food Common adulterants

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(a) CODEX ALIMENTARIUS : The Codex Alimentarius Commission, which is the principal organ of
the joint FAO/ WHO Food Standards Programme formulates food standards for international market. The
food standards in India are based on the standards of the codex alimentarius.
(b) PFA STANDARDS : Under the Prevention of Food Adulteration Act (1954) standards have been
established which are revised from time to time by the "Central Committee for Food Standards". The
purpose of the PFA standards is to obtain a minimum level of quality of foodstuffs attainable under Indian
conditions.
(c) THE AGMARK STANDARDS : These standards are set by the Directorate of Marketing and
Inspection of the Government of India. The Agmark gives the consumer an assurance of quality in
accordance with the standards laid down.
(d) BUREAU OF INDIAN STANDARDS : The ISI mark on any article of food is a guarantee of good
quality in accordance with the standards prescribed by the Bureau of Indian Standards for that commodity.
The Agmark and ISI standards are not mandatory; they are purely voluntary. They express degrees of
excellence above PFA standards.

23. FOOD CONTAMINANTS
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 Potentially hazardous chemicals may contaminate foods from a variety of sources,
including
Agricultural
chemicals
Industrial
contaminants
Natural
contaminants
Processing-
induced
contaminants

24. AGRICULTURAL CHEMICALS
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1. Insecticides are added to foods to control insect pests. Insecticides fall into several major
categories-
 organochlorine compounds (dichlorodiphenyltrichloro ethane [DDT], chlordane)
 organophosphate compounds (e.g., parathion and malathion)
 carbamate compounds (e.g., carbaryl and aldicarb)
 botanical compounds (e.g., nicotine and pyrethrum) and inorganic compounds (e.g.,
arsenicals).
Organophosphorus and
carbamates are
neurotoxins
Cholinesterase inhibitors
Act by blocking synaptic
nerve trnsmission

25. AGRICULTURAL CHEMICALS (contd.)
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 Insecticide residues in foods pose a low degree of hazard for several reasons:
(a) the level of exposure is very low
(b) some insecticides are not very toxic to humans
(c) some insecticides decompose rapidly in the environment
(d) many different insecticides are used, which limits exposure to any one
particular insecticide

26. AGRICULTURAL CHEMICALS (contd.)
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 Herbicides are applied to agricultural crops to control the growth of weeds. Several classes of
herbicides include
 chlorophenoxy compounds (e.g., 2,4-D)
 dinitrophenols (e.g., dinitroorthocresol)
 bipyridyl compounds (e.g., paraquat)
 substituted ureas (e.g., monuron)
 carbamates (e.g., propham)
 triazines (e.g., simazine).
• In most circumstances, herbicide residues in foods do not present any hazard to consumers. Food
poisoning incidents have never resulted from the proper use of herbicides on food crops.
• Exception:- bipyridyl-toxic to humans

27. AGRICULTURAL CHEMICALS (contd.)
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 Fertilizers are typically combinations of nitrogen and phosphorus compounds. Nitrogen
fertilizers are oxidized to nitrate and nitrite in the soil.
Nitrate
Nitrite
HARMFUL
Plants such
as spinach
Overly
fertilized
field
Accumulation of
nitrate
Presence of
nitrate-
reducing
bacteria
Nitrite

28. INDUSTRIAL CHEMICALS
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 Food contamination with polychlorinated
biphenyls (PCBs) and polybrominated
biphenyls (PBBs) has occurred on several
occasions . PCBs and PBBs are persistent in the
environment.
 These compounds are fat soluble so they tend to
accumulate in the fat depots of various
organisms; concentrations often magnify upward
along the food chain.
 PBBs = used as fire retardants.
 PCBs = used in transformer fluid.
 Mercury (Minamata disease)
 The symptoms included tremors and other
neurotoxic effects and kidney failure.

29. Chemicals Migrating from Packaging Materials and
Containers
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•
BPA is a monomer used in the manufacture of
plastics including the production of polycarbonate
resins used to make baby bottles and water bottles
and in the epoxy resins used as the internal linings
of cans for soft drinks and beer.
effects on the brain, behavior, and prostate glands
in fetuses, infants and children
•
The main issue with lead contamination results
from the occasional use of lead-based glazes on
pottery or paint on glassware that may come in
contact with acidic foods or beverages.
 Lead is a well-known toxicant that can affect the
nervous system, the kidney, and the bone
Metal cans for food storage are typically
constructed using tin plate. These cans have inner
surfaces that are lined with a lacquer material when
cans are used for acidic foods or beverages.
Because tin is poorly absorbed, the primary
symptoms are bloating, nausea, abdominal cramps,
vomiting, diarrhea, and headache.
The inappropriate storage of acidic foods or
beverages in galvanized containers can result in acute
zinc intoxication .
The symptoms of zinc intoxication include irritation
of the mouth, throat, and abdomen; nausea; vomiting;
dizziness; and collapse.

30. NATURAL CONTAMINANTS
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 Bacterial Toxins
 The best examples of bacterial intoxication are the staphylococcal enterotoxins and botulinal toxins.

31. NATURAL CONTAMINANTS (contd.)
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Algal toxins

32. NATURAL CONTAMINANTS (contd.)
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 Paralytic shellfish poisoning occurs as the result of ingesting molluscan shellfish, such as clams, mussels,
cockles, and scallops, which have become poisonous by feeding on toxic dinoflagellate algae.
 Toxic dinoflagellate algae belonging to three genera—Alexandrium, Gymnodinium, and Pyrodinium—
have been implicated .
 Because the blooms of the toxic dinoflagellates are quite sporadic, most shellfish will be hazardous only
during the times of the blooms.
 Saxitoxins are the causative agents involved in paralytic shellfish poisoning. Saxitoxins bind to and block
the sodium channels in nerve membranes.
 The symptoms of paralytic shellfish poisoning include a tingling sensation and numbness of the lips,
tongue, and fingertips followed by numbness in the legs, arms, and neck; ataxia; giddiness; staggering;
drowsiness; incoherent speech progressing to aphasia; rash; fever; and respiratory and muscular paralysis.

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 Mycotoxins
 Mycotoxins are produced by a wide variety of molds that can grow on many different foods.
• The aflatoxins are produced primarily by Aspergillus
flavus and Aspergillus parasiticus, molds that often
contaminate peanuts and corn.
• Aflatoxin = act as carcinogen
AFLATOXIN
• Fusarium molds produce a number of different mycotoxins,
including the trichothecenes, fumonisins, and zearalenone.
• Fumonisins are produced primarily by Fusarium
verticillioides.
• The fumonisins have been implicated in equine leuko-
encephalomalacia, a fatal neurotoxic syndrome in horses.
TOXINS BY
FUSARIUM
MOLDS

34. PROCESSING-INDUCED TOXICANTS
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 Processing-induced toxicants form under certain processing conditions, especially heat treatment.
 Several examples of processed-induced toxicants, such as heterocyclic aromatic amines,
hydroxymethylfurfural, advanced glycation end products, nitrosamines, and acrylamide.
 Acrylamide will form due to a reaction between the amino acid, asparagine, and reducing sugars such as
glucose and fructose under elevated temperatures (higher than 120°C) and in low-moisture conditions.
 The highest levels of acrylamide are found in fried, baked, and broiled foods.
 Acrylamide is rapidly absorbed from the gastrointestinal tract and is distributed throughout the body
where it is metabolized to form glycidamide, which is a reactive epoxide that is thought to be
responsible for the genotoxic effects of acrylamide exposure.

35. NATURAL TOXICANTS
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.

36. EXAMPLS OF NATURAL TOXICANTS
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Foxglove- digitalis
Jimsonweed- atropine
Cassava, lima beans- cyanogenic glycosides
Spinach- oxalates
Potatoes- solanine and chaconine
Only when
consumed in large
amounts.

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