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1. Session 1 1st draft
Science and Food
Contents
Introduction
1.1 What is Food science
1.2 Four basic food types
1.3 Five Basic Tastes in Food
1.4 Your Digestive System
1.5 What is a flavor
1.6 What is MSG?
1.7 What is Molecular Gastronomy?
Summary
Learning Outcomes
Introduction
Food Science can be denned as the application of the basic sciences and engineering to study the
fundamental physical, chemical, and biochemical nature of foods and the principles of food
processing. ... Because food interacts directly with people.
1.1 What is Food Science?
Food Science is a multi-disciplinary field involving chemistry, biochemistry, nutrition,
microbiology and engineering to give one the scientific knowledge to solve real problems
associated with the many facets of the food system. The basis of the discipline lies in an
understanding of the chemistry of food components, such as proteins, carbohydrates, fats and
water and the reactions they undergo during processing and storage. A complete understanding
of processing and preservation methods is required including drying, freezing, pasteurization,
canning, irradiation, extrusion, to name just a few. The ability to carry out analysis of food
constituents is developed along with statistical quality control methods. The microbiology and

2. the safety aspects of food must also be understood. Other topics covered include food additives,
the physico-chemical properties of food, flavor chemistry, product development, food
engineering and packaging. Food science integrates this broad-based knowledge and focuses it
on food.
Food Science is still a relatively new and growing discipline, brought about mainly as a response
to the social changes taking place in many parts of the developed world. The food industry,
which originally provided only primary products for final preparation in the home, finds itself
responding to market demands for more refined, sophisticated, and convenient products. The
demand for easy to prepare, convenience foods, poses major scientific and technological
challenges which cannot be met without highly trained scientists capable of understanding the
complex chemistry/biochemistry of food systems and knowledge of the methods to preserve
them. This increased reliance of society on ready-to-eat foods has led to greater responsibility for
processors in terms of quality, safety and nutrition. In order to ensure high quality and
competitive products, scientific principles and new technologies are being applied to food
manufacturing and the body of knowledge required has become that discipline called Food
Science. Although cooking may have once been considered a less desirable job, today chefs are a
new breed- respected, even admired, for their skill, craftsmanship and even artistry. Some chefs
have received so much press coverage that their names are household words. The elevation of the
status of the chef helps attract bright and talented people to the industry.
1.1 What are the four basic food types
The four basic food types are given below.
1.1.1 Carbohydrates
Carbohydrates (literally hydrates of carbon) are chemical compounds which act as the primary
biological means of storing or consuming energy; other forms being via fat and protein.
Relatively complex carbohydrates are known as polysaccharides. The simplest carbohydrates are
monosaccharides, which are small straight-chain aldehydes and ketones with many hydroxyl
groups added, usually one on each carbon except the functional group. Other carbohydrates are

3. composed of monosaccharide units, and break down under hydrolysis. These may be classified
as disaccharides, oligosaccharides, or polysaccharides, depending on whether they have two,
several, or many monosaccharide units.
Carbohydrates or saccharides (Greek sakcharon, "sugar") are simple molecules that are straight-
chain aldehydes or ketones with many hydroxyl groups added, usually one on each carbon atom
that is not part of the aldehyde or ketone functional group. Carbohydrates are the most abundant
biological molecules, and fill numerous roles in living things, such as the storage and transport of
energy (starch, glycogen) and structural components (cellulose in plants, chitin in animals).
Additionally, carbohydrates and their derivatives play major roles in the functioning of the
immune system, fertilization, pathogenesis, blood clotting, and development.
The basic carbohydrate units are called monosaccharides, such as glucose, galactose, and
fructose. The general chemical formula of an unmodified monosaccharide is (C·H2O)n, where n
is any number of three or greater. All carbohydrates have a hydrogen to oxygen ratio of
2:1.Monosaccharides can be linked together in almost limitless ways. Two joined
monosaccharides are called disaccharides, such as sucrose and lactose. Carbohydrates containing
between about three to six monosaccharide units are termed oligosaccharides; anything larger
than this is a polysaccharide. Polysaccharides, such as starch, glycogen, or cellulose, can reach
many thousands of units in length. This is one of the main ingredients in cookery related to
pastry and bakery work.
1.1.2 Fats
In biochemistry, fat is a generic term for a class of lipids. Fats are produced by organic processes
in animals and plants. All fats are insoluble in water and have a density significantly below that
of water (i.e. they float on water.) Fats that are liquid at room temperature are often referred to as
oil. Most fats are composed primarily of triglycerides; some monoglycerides and diglycerides are
mixed in, produced by incomplete esterification. These are extracted and used as an ingredient.

4. Products with a lot of saturated fats tend to be solid at room temperature, while products
containing unsaturated fats, which include monounsaturated fats and polyunsaturated fats, tend
to be liquid at room temperature. Predominantly saturated fats (solid at room temperature)
include all animal fats (e.g. milk fat, lard, tallow), as well as palm oil, coconut oil, cocoa fat and
hydrogenated vegetable oil (shortening). All other vegetable fats, such as those coming from
olive, peanut, maize (corn oil), cottonseed, sunflower, safflower, and soybean, are predominantly
unsaturated and remain liquid at room temperature. However, both vegetable and animal fats
contain saturated and unsaturated fats. Some oils (such as olive oil) contain in majority
monounsaturated fats, while others present quite a high percentage of polyunsaturated fats
(sunflower, rape).
1.1.3 Proteins
A protein is a complex, high molecular weight organic compound that consists of amino acids
joined by peptide bonds. Protein is essential to the structure and function of all living cells and
viruses. Many proteins are enzymes or subunits of enzymes. Other proteins play structural or
mechanical roles, such as those that form the struts and joints of the "cytoskeleton." Proteins are
also nutrient sources for organisms that do not produce their own energy from sunlight. Proteins
differ from carbohydrates chiefly in that they contain much nitrogen and a little bit of sulfur,
besides carbon, oxygen and hydrogen. Proteins are a primary constituent of living things.
In carnivores protein is one of the largest component of the diet. The metabolism of proteins by
the body releases ammonia, an extremely toxic substance. It is then converted in the liver into
urea, a much less toxic chemical, which is excreted in urine. Some animals convert it into uric
acid instead.
1.1.4 Protein nutrition
In terms of human nutritional needs, proteins come in two forms: complete proteins contain all
eight of the amino acids that humans cannot produce themselves, while incomplete proteins lack
or contain only a very small proportion of one or more. Humans' bodies can make use of all the

5. amino acids they extract from food for synthesizing new proteins, but the inessential ones
themselves need not be supplied by the diet, because our cells can make them ourselves. When
protein is listed on a nutrition label it only refers to the amount of complete proteins in the food,
though the food may be very strong in a subset of the essential amino acids. Animal-derived
foods contain all of those amino acids, while plants are typically stronger in some acids than
others. Complete proteins can be made in an all vegan diet by eating a sufficient variety of foods
and by getting enough calories. It was once thought that in order to get the complete proteins
vegans needed to do protein combining by getting all amino acids in the same meal (the most
common example is eating beans with rice) but nutritionists now know that the benefits of
protein combining can be achieved over the longer period of the day. Ovo-lacto vegetarians
usually do not have this problem, since egg's white and cow's milk contain all essential amino
acids. Peanuts, soy milk, nuts, seeds, green peas, Legumes, the alga spirulina and some grains are
some of the richest sources of plant protein.
 1 gram of Carbohydrates contains 3.75 calories.
 1 gram of fat contains 9 calories.
 1 gram of protein contains 4 calories.
 1 gram of alcohol contains 7 calories.
1.3 Five Basic Tastesin Food
Scientists describe seven basic tastes: bitter, salty, sour, astringent, sweet, pungent (eg chili), and
umami. There are however five basic tastes that the tongue is sensitive to: salt, sweet, bitter,
sour, and umami, the taste of MSG. Umami is a Japanese word meaning "savory" or "meaty" and
thus applies to the sensation of savoriness -- specifically, to the detection of glutamates, which
are especially common in meats, cheese and other protein-heavy foods. The action of umami
receptors explains why foods treated with monosodium glutamate often taste fuller or just better.
Umami, which has been quietly enjoyed by Eastern civilizations for years, was recently brought
to the forefront of western thought by the discovery by the University of Miami of the actual
receptors responsible for the sense of umami, a modified form of mGluR4, in which the end of

6. the molecule is missing. The researchers named it 'taste-mGluR4'. The discovery of the receptor
is interesting especially since the receptor for bitter has not yet been identified.
1.4 Main five basic tastes
Saltiness
Saltiness is a taste produced by the presence of sodium chloride (and to a lesser degree other
salts). The ions of salt, especially sodium (Na+), can pass directly through ion channels in the
tongue, leading to an action potential.
Sourness
Sourness is the taste that detects acids. The mechanism for detecting sour taste is similar to that
which detects salt taste. Hydrogen ion channels detect the concentration of hydronium ions
(H3O+ ions) that have dissociated from an acid. Hydrogen ions are capable of permeating the
amiloride-sensitive sodium channels, but this is not the only mechanism involved in detecting the
quality of sourness. Hydrogen ions also inhibit the potassium channel, which normally functions
to hyperpolarize the cell. Thus, by a combination of direct intake of hydrogen ions (which itself
depolarizes the cell) and the inhibition of the hyperpolarizing channel, sourness causes the taste
cell to fire in this specific manner.
Sweetness
Sweetness Sweetness is produced by the presence of sugars, some proteins and a few other
substances. Sweetness is often connected to aldehydes and ketones which contain carbonyl
group. Sweetness is detected by a variety of G protein coupled receptors coupled to the G protein
gustducin found on the taste buds. At least two different variants of the "sweetness receptors"
need to be activated for the brain to register sweetness. The compounds which the brain senses as
sweet are thus compounds that can bind with varying bond strength to several different
sweetness receptors. The differences between the different sweetness receptors is mainly in the

7. binding site of the G protein coupled receptors. The average human detection threshold for
sucrose is 10 millimoles per litre. For lactose it is 30 millimoles per liter, and 5-Nitro-2-
propoxyaniline 0.002 millimoles per litre.
Bitterness
Bitterness is the taste which detects bases. Bitterness, like sweetness, is sensed by G protein
coupled receptors coupled to the G protein gustducin. Many people find bitter tastes to be
unpleasant; many alkaloids taste bitter, and evolutionary biologists have suggested that a distaste
for bitter things evolved because it enabled people to avoid accidental poisoning. The bitterest
substance known is the synthetic chemical denatonium, marketed as the trademarked Bitrex [2],
discovered in 1958. Denatonium benzoate is a white, odourless solid used as an aversive agent,
and can be an additive that prevents accidental ingestion of a toxic substance by humans,
particularly children, and by animals. It is commonly used on denaturizing ethanol. The synthetic
substance phenylthiocarbamide (PTC) tastes very bitter to most people, but is virtually tasteless
to others; furthermore, among the tasters, some are so-called "supertasters" to whom PTC is
extremely bitter. This genetic variation in the ability to taste a substance has been a source of
great interest to those who study genetics. In addition, it is of interest to those who study
evolution since PTC-tasting is associated with the ability to taste numerous natural bitter
compounds, a large number of which are known to be toxic. Quinine, the anti-malarial
prophylactic, is also known for its bitter taste and is found in tonic water. Bitter taste receptors
are known specifically as T2R's (taste receptors, type 2). They are identified not only by their
ability to taste for certain "bitter" ligands, but also by the morphology of the receptor itself
(surface bound, monomeric)[3].
Savouriness (Umami)
Savouriness is the name for the taste sensation produced by the free glutamates commonly found
in fermented and aged foods. In English, it is sometimes described as "meaty" or "savoury". In
the Japanese, the term umami is used for this taste sensation, whose characters literally mean
"delicious flavour." Umami is now the commonly used term by taste scientists. The same taste is

8. referred to as xianwèi in Chinese cooking. Savoury is considered a fundamental taste in Japanese
and Chinese cooking, but is not discussed as much in Western cuisine.
Examples of food containing these free glutamates (and thus strong in the savoury taste) are
parmesan and roquefort cheese as well as soy sauce and fish sauce. It is also found in significant
amounts in various unfermented foods such as walnuts, grapes, broccoli, tomatoes, and
mushrooms, and to a lesser degree in meat. The glutamate taste sensation is most intense in
combination with sodium. This is one reason why tomatoes exhibit a stronger taste after adding
salt. Sauces with savoury and salty tastes are very popular for cooking, such as tomato sauces
and ketchup for Western cuisines and soy sauce and fish sauce for East Asian and Southeast
Asian cuisines. Since not every glutamate produces a savoury-like taste sensation, there is
continuing investigation into the exact mechanism of how the savoury taste sensation is
produced.
The additive monosodium glutamate (MSG), which was developed as a food additive in 1907 by
Kikunae Ikeda, produces a strong savoury taste. Savoury is also provided by the nucleotides
disodium 5’-inosine monophosphate (IMP) and disodium 5’-guanosine monophosphate (GMP).
These are naturally present in many protein-rich foods. IMP is present in high concentrations in
many foods, including dried skipjack tuna flakes used to make dashi, a Japanese broth. GMP is
present in high concentration in dried shiitake mushrooms, used in much of the cuisine of Asia.
There is a synergistic effect between MSG, IMP and GMP which together in certain ratios
produce a strong umami taste. A subset of savoury taste buds responds specifically to glutamate
in the same way that sweet ones respond to sugar. Glutamate binds to a variant of G protein
coupled glutamate receptors.
Role of Temperature as a 'False Heat' or ‘False Coolness'
False Coolness -- Some substances activate cold trigeminal receptors. One can sense a cool
sensation (also known as "cold", "fresh" or "minty") from, e.g., spearmint, menthol, ethanol or
camphor, which is caused by the food activating the TRP-M8 ion channel on nerve cells that
signal cold. The reactions behind this sense are therefore analogous to those behind the hot

9. sense. Unlike the actual change in temperature described for sugar substitutes, coolness is only a
perceived phenomena.
Spiciness or (false) heat --Substances such as ethanol and capsaicin cause a burning sensation by
inducing a trigeminal nerve reaction together with normal taste reception. The heat is caused by
the food activating a nerve cell ion channel called TRP-V1, which is also activated by hot
temperatures. The sensation, usually referred to as "hot" or "spicy", is a notable feature of
Mexican, Indian, Tex-Mex, Szechuan, Korean, and Thai cuisine. The two main plants providing
this sensation are chili peppers (those fruits of the Capsicum plant that contain capsaicin) and
black pepper.
Astringency
Some foods, such as tea or unripe fruits, contain tannins that constrict organic tissue. The best
example of this is unripe persimmons, whose juice causes a very unpleasant astringent sensation
on any part of the mouth it touches. Less exact terms for the astringent sensation include:
"rubbery", "hard", "styptic", "dry", "rough", "harsh" (especially for wine) and "tart" (normally
referring to sourness).
1.4 Your Digestive System and How It Works
The digestive system is a series of hollow organs joined in a long, twisting tube from the mouth
to the anus (see figure). Inside this tube is a lining called the mucosa. In the mouth, stomach, and
small intestine, the mucosa contains tiny glands that produce juices to help digest food.
Two solid organs, the liver and the pancreas, produce digestive juices that reach the intestine
through small tubes. In addition, parts of other organ systems (for instance, nerves and blood)
play a major role in the digestive system.
The food digestive system
Why is digestion important?

10. When we eat such things as bread, meat, and vegetables, they are not in a form that the body can
use as nourishment. Our food and drink must be changed into smaller molecules of nutrients
before they can be absorbed into the blood and carried to cells throughout the body. Digestion is
the process by which food and drink are broken down into their smallest parts so that the body
can use them to build and nourish cells and to provide energy.
How is food digested?
Digestion involves the mixing of food, its movement through the digestive tract, and the
chemical breakdown of the large molecules of food into smaller molecules. Digestion begins in
the mouth, when we chew and swallow, and is completed in the small intestine. The chemical
process varies somewhat for different kinds of food.
Movement of Food Through the System
The large, hollow organs of the digestive system contain muscle that enables their walls to move.
The movement of organ walls can propel food and liquid and also can mix the contents within
each organ. Typical movement of the esophagus, stomach, and intestine is called peristalsis. The
action of peristalsis looks like an ocean wave moving through the muscle. The muscle of the
organ produces a narrowing and then propels the narrowed portion slowly down the length of the
organ. These waves of narrowing push the food and fluid in front of them through each hollow
organ.
The first major muscle movement occurs when food or liquid is swallowed. Although we are
able to start swallowing by choice, once the swallow begins, it becomes involuntary and
proceeds under the control of the nerves.
The esophagus is the organ into which the swallowed food is pushed. It connects the throat
above with the stomach below. At the junction of the esophagus and stomach, there is a ringlike
valve closing the passage between the two organs. However, as the food approaches the closed
ring, the surrounding muscles relax and allow the food to pass.

11. The food then enters the stomach, which has three mechanical tasks to do. First, the stomach
must store the swallowed food and liquid. This requires the muscle of the upper part of the
stomach to relax and accept large volumes of swallowed material. The second job is to mix up
the food, liquid, and digestive juice produced by the stomach. The lower part of the stomach
mixes these materials by its muscle action. The third task of the stomach is to empty its contents
slowly into the small intestine.
Several factors affect emptying of the stomach, including the nature of the food (mainly its fat
and protein content) and the degree of muscle action of the emptying stomach and the next organ
to receive the contents (the small intestine). As the food is digested in the small intestine and
dissolved into the juices from the pancreas, liver, and intestine, the contents of the intestine are
mixed and pushed forward to allow further digestion.
Finally, all of the digested nutrients are absorbed through the intestinal walls. The waste products
of this process include undigested parts of the food, known as fiber, and older cells that have
been shed from the mucosa. These materials are propelled into the colon, where they remain,
usually for a day or two, until the feces are expelled by a bowel movement.
Production of Digestive Juices
The glands that act first are in the mouth—the salivary glands. Saliva produced by these glands
contains an enzyme that begins to digest the starch from food into smaller molecules.
The next set of digestive glands is in the stomach lining. They produce stomach acid and an
enzyme that digests protein. One of the unsolved puzzles of the digestive system is why the acid
juice of the stomach does not dissolve the tissue of the stomach itself. In most people, the
stomach mucosa is able to resist the juice, although food and other tissues of the body cannot.
After the stomach empties the food and juice mixture into the small intestine, the juices of two
other digestive organs mix with the food to continue the process of digestion. One of these
organs is the pancreas. It produces a juice that contains a wide array of enzymes to break down

12. the carbohydrate, fat, and protein in food. Other enzymes that are active in the process come
from glands in the wall of the intestine or even a part of that wall.
The liver produces yet another digestive juice—bile. The bile is stored between meals in the
gallbladder. At mealtime, it is squeezed out of the gallbladder into the bile ducts to reach the
intestine and mix with the fat in our food. The bile acids dissolve the fat into the watery contents
of the intestine, much like detergents that dissolve grease from a frying pan. After the fat is
dissolved, it is digested by enzymes from the pancreas and the lining of the intestine.
Absorption and Transport of Nutrients
Digested molecules of food, as well as water and minerals from the diet, are absorbed from the
cavity of the upper small intestine. Most absorbed materials cross the mucosa into the blood and
are carried off in the bloodstream to other parts of the body for storage or further chemical
change. As already noted, this part of the process varies with different types of nutrients.
Carbohydrates. It is recommended that about 55 to 60 percent of total daily calories be from
carbohydrates. Some of our most common foods contain mostly carbohydrates. Examples are
bread, potatoes, legumes, rice, spaghetti, fruits, and vegetables. Many of these foods contain both
starch and fiber.
The digestible carbohydrates are broken into simpler molecules by enzymes in the saliva, in juice
produced by the pancreas, and in the lining of the small intestine. Starch is digested in two steps:
First, an enzyme in the saliva and pancreatic juice breaks the starch into molecules called
maltose; then an enzyme in the lining of the small intestine (maltase) splits the maltose into
glucose molecules that can be absorbed into the blood. Glucose is carried through the
bloodstream to the liver, where it is stored or used to provide energy for the work of the body.
Table sugar is another carbohydrate that must be digested to be useful. An enzyme in the lining
of the small intestine digests table sugar into glucose and fructose, each of which can be
absorbed from the intestinal cavity into the blood. Milk contains yet another type of sugar,

13. lactose, which is changed into absorbable molecules by an enzyme called lactase, also found in
the intestinal lining.
Protein. Foods such as meat, eggs, and beans consist of giant molecules of protein that must be
digested by enzymes before they can be used to build and repair body tissues. An enzyme in the
juice of the stomach starts the digestion of swallowed protein. Further digestion of the protein is
completed in the small intestine. Here, several enzymes from the pancreatic juice and the lining
of the intestine carry out the breakdown of huge protein molecules into small molecules called
amino acids. These small molecules can be absorbed from the hollow of the small intestine into
the blood and then be carried to all parts of the body to build the walls and other parts of cells.
Fats. Fat molecules are a rich source of energy for the body. The first step in digestion of a fat
such as butter is to dissolve it into the watery content of the intestinal cavity. The bile acids
produced by the liver act as natural detergents to dissolve fat in water and allow the enzymes to
break the large fat molecules into smaller molecules, some of which are fatty acids and
cholesterol. The bile acids combine with the fatty acids and cholesterol and help these molecules
to move into the cells of the mucosa. In these cells the small molecules are formed back into
large molecules, most of which pass into vessels (called lymphatics) near the intestine. These
small vessels carry the reformed fat to the veins of the chest, and the blood carries the fat to
storage depots in different parts of the body.
Vitamins. Another vital part of our food that is absorbed from the small intestine is the class of
chemicals we call vitamins. The two different types of vitamins are classified by the fluid in
which they can be dissolved: water-soluble vitamins (all the B vitamins and vitamin C) and fat-
soluble vitamins (vitamins A, D, and K).
Water and salt. Most of the material absorbed from the cavity of the small intestine is water in
which salt is dissolved. The salt and water come from the food and liquid we swallow and the
juices secreted by the many digestive glands.
How is the digestive process controlled?

14. Hormone Regulators
A fascinating feature of the digestive system is that it contains its own regulators. The major
hormones that control the functions of the digestive system are produced and released by cells in
the mucosa of the stomach and small intestine. These hormones are released into the blood of the
digestive tract, travel back to the heart and through the arteries, and return to the digestive
system, where they stimulate digestive juices and cause organ movement.
The hormones that control digestion are gastrin, secretin, and cholecystokinin (CCK):
Gastrin causes the stomach to produce an acid for dissolving and digesting some foods. It is also
necessary for the normal growth of the lining of the stomach, small intestine, and colon.
Secretin causes the pancreas to send out a digestive juice that is rich in bicarbonate. It stimulates
the stomach to produce pepsin, an enzyme that digests protein, and it also stimulates the liver to
produce bile.
CCK causes the pancreas to grow and to produce the enzymes of pancreatic juice, and it causes
the gallbladder to empty.
Additional hormones in the digestive system regulate appetite:
Ghrelin is produced in the stomach and upper intestine in the absence of food in the digestive
system and stimulates appetite.
Peptide YY is produced in the GI tract in response to a meal in the system and inhibits appetite.
Both of these hormones work on the brain to help regulate the intake of food for energy.
Nerve Regulators
Two types of nerves help to control the action of the digestive system. Extrinsic (outside) nerves
come to the digestive organs from the unconscious part of the brain or from the spinal cord. They
release a chemical called acetylcholine and another called adrenaline. Acetylcholine causes the

15. muscle of the digestive organs to squeeze with more force and increase the "push" of food and
juice through the digestive tract. Acetylcholine also causes the stomach and pancreas to produce
more digestive juice. Adrenaline relaxes the muscle of the stomach and intestine and decreases
the flow of blood to these organs.
Even more important, though, are the intrinsic (inside) nerves, which make up a very dense
network embedded in the walls of the esophagus, stomach, small intestine, and colon. The
intrinsic nerves are triggered to act when the walls of the hollow organs are stretched by food.
They release many different substances that speed up or delay the movement of food and the
production of juices by the digestive organs.
Activity 1.1
 Visit the hyperlink https://www.usda.gov/topics/food-and-nutrition,in the
section Supplemental Nutrition Assistance Program read the article
Nutrition Assistance based on the information write a summary (250
words) on the Nutrition Assistance given to the general public on Food
and nutrition.
1.5 What is Flavor?
Flavor is the sensory impression of a food or other substance, and is determined mainly by the
chemical senses of taste and smell. The "trigeminal senses", which detect chemical irritants in

16. the mouth and throat, may also occasionally determine flavor. The flavor of the food, as such,
can be altered with natural or artificial flavorants, which affect these senses.
Of the three chemical senses, smell is the main determinant of a food item's flavor. While the
taste of food is limited to sweet, sour, bitter, salty, umami, and other basic tastes, the smells of a
food are potentially limitless. A food's flavor, therefore, can be easily altered by changing its
smell while keeping its taste similar. No where is this better exemplified than in artificially
flavored jellies, soft drinks and candies, which, while made of bases with a similar taste, have
dramatically different flavors due to the use of different scents or fragrances.
Although the terms "flavoring" or "flavorants" in common language denote the combined
chemical sensations of taste and smell, the same terms are usually used in the fragrance and
flavors industry to refer to edible chemicals and extracts that alter the flavor of food and food
products through the sense of smell. Due to the high cost or unavailability of natural flavor
extracts, most commercial flavorants are nature-identical, which means that they are the
chemical equivalent of natural flavors but chemically synthesized rather than being extracted
from the source materials.
Flavorants
Flavorants are focused on altering or enhancing the flavors of natural food product such as meats
and vegetables, or creating flavor for food products that do not have the desired flavors such as
candies and other snacks. Most types of flavorants are focused on scent and taste. Few
commercial products exist to stimulate the trigeminal senses, since these are sharp, astringent,
and typically unpleasant flavors.
The precise definition of a flavorant is difficult since its literal definition includes anything that
contributes flavor to food. A legal definition by the U.S. Code of Federal Regulations, a natural
flavorant[1] is:
"the essential oil, oleoresin, essence or extractive, protein hydrolysate, distillate, or any product
of roasting, heating or enzymolysis, which contains the flavoring constituents derived from a

17. spice, fruit or fruit juice, vegetable or vegetable juice, edible yeast, herb, bark, bud, root, leaf or
any other edible portions of a plant, meat, seafood, poultry, eggs, dairy products, or fermentation
products thereof, whose primary function in food is flavoring rather than nutritional."
Artificial flavorants are chemically synthesized compounds that are used to flavor food items but
do not meet the specifications listed above. Artificial flavorants are often formulated with the
same chemical compounds found in natural flavorants.
Although slightly different, the European Union's guidelines for natural flavorants are somewhat
similar. In addition, certain artificial flavorants are given an E number, which may be included
on food labels.
Smell
Smell flavorants, or simply, flavorants, are engineered and composed in similar ways as with
industrial fragrances and fine perfumes. To produce natural flavors, the flavorant must first be
extracted from the source substance. The methods of extraction can involve solvent extraction,
distillation, or using force to squeeze it out. The extracts are then usually further purified and
subsequently added to food products to flavor them. To begin producing artificial flavors, flavor
manufacturers must either find out the individual naturally occurring aroma chemicals and mix
them appropriately to produce a desired flavor or create a novel non-toxic artificial compound
that gives a specific flavor.
Most artificial flavors are specific and often complex mixtures of singular naturally occurring
flavor compounds combined together to either imitate or enhance a natural flavor. These
mixtures are formulated by flavorist to give a food product a unique flavor and to maintain flavor
consistency between different product batches or after recipe changes. The list of known
flavoring agents includes thousands of molecular compounds, and the flavor chemist (flavorist)
can often mix these together to produce many of the common flavors.
Chemical Odor
Diacetyl Buttery
Isoamyl acetate Banana

18. Cinnamic aldehyde Cinnamon
Ethyl propionate Fruity
Limonene Orange
Ethyl-(E, Z)-2,4-decadienoate Pear
Allyl hexanoate Pineapple
Ethyl maltol Sugar, Cotton candy
Methyl salicylate Wintergreen
Benzaldehyde Bitter almond
The compounds used to produce artificial flavors are almost identical to those that occur
naturally, and a natural origin for a substance does not necessarily imply that it is safe to
consume. In fact, artificial flavors are considered somewhat safer to consume than natural flavors
due to the standards of purity and mixture consistency that are enforced either by the company or
by law. Natural flavors in contrast may contain toxins from their sources while artificial flavors
are typically more pure and are required to undergo more testing before being sold for
consumption.
Flavors from food products are usually result of a combination of natural flavors, which set up
the basic smell profile of a food product while artificial flavors modify the smell to accent it.
Taste
While salt and sugar can technically be considered flavorants that enhance salty and sweet tastes,
usually only compounds that enhance umami, as well as other secondary flavors are considered
taste flavorants. Artificial sweeteners are also technically flavorants.
Umami or "savory" flavorants, more commonly called "taste enhancers" are largely based on
Amino acids and Nucleotides. These are manufactured as sodium or calcium salts. Umami
flavorants recognized and approved by the European Union include:

19. Glutamic acid salts: This amino acid's sodium salt, monosodium glutamate (MSG) is one of the
most commonly used flavor enhancers in food processing. Mono and diglutamate salts are also
commonly used.
Glycine salts: A simple amino acid that is usually used in conjunction with glutamic acid as a
flavor enhancer.
Guanylic acid salts: Nucleotide salts that is usually used in conjunction with glutamic acid as a
flavor enhancer.
Inosinic acid salts: Nucleotide salts created from the breakdown of AMP. Due to high costs of
production, it is usually used in conjunction with glutamic acid as a flavor enhancer.
5'-ribonucleotides salts:
Certain organic acids can be used to enhance sour tastes, but like salt and sugar these are usually
not considered and regulated as flavorants under law. Each acid imparts a slightly different sour
or tart taste that alters the flavor of a food.
Acetic acid: gives vinegar its sour taste and distinctive smell
Citric acid: found in citrus fruits and gives them their sour taste
Lactic acid: found in various milk products and give them a rich tartness
Malic acid: found in apples and gives them their sour/tart taste
Tartaric acid: found in grapes and wines and gives them a tart taste
1.5 What is MSG - Monosodium Glutamate
Monosodium glutamate, sodium glutamate, flavour enhancer 621 EU food additive code: E621.
HS code: 29224220. (IUPAC names: 2-aminopentanedioic acid, 2-aminoglutaric acid, 1-
aminopropane-1,3-dicarboxylic acid), commonly known as MSG, Ajinomoto or Vetsin, is a
sodium salt of glutamic acid. MSG is a food additive, popularly marketed as a "flavour
enhancer". It was discovered and patented in 1909 by Ajinomoto Corporation in Japan. In its
pure form, it appears as a white crystalline powder; when dissolved in water (or saliva) it rapidly
dissociates into free sodium and glutamate ions (glutamate is the anionic form of glutamic acid, a
naturally occurring amino acid).

20. How does MSG work?
MSG stimulates specific receptors located in taste buds such as the amino acid receptor
T1R1/T1R3 or other glutamate receptors like the metabotropic receptors (mGluR4 and mGluR1)
which induce the taste known as umami, one of the five basic tastes (the word umami is a
loanword from Japanese; it is also referred to as "savory" or "meaty").
The umami taste may have evolved to help animals ingest food that have high protein content
and is of significant importance to the food industry because of its flavor enhancement
properties.
Sources of glutamate
Natural Occurrence
Glutamate itself is a widespread amino acid: it is found naturally in human bodies and in protein-
containing foods, such as peas, mushrooms, seaweed, tomatoes, fermented soy products, yeast
extracts, nuts, legumes, meats and most dairy products. Some of the glutamate in foods is in a
"free" form; and only this free form of glutamate can enhance the flavor of foods. Part of the
flavour-enhancing effect of tomatoes, certain cheeses, and fermented or hydrolyzed protein
products (such as soy sauce and soy bean paste) is therefore due to the presence of free
glutamate. Asian cuisine originally used a natural seaweed broth, such as kelp, to bring up the
umami taste in soups. Manufacturers, such as Ajinomoto, use selected strains of Micrococcus
glutamicus bacteria in a bath of nutrient. The bacteria are selected for their ability to excrete
glutamic acid, which is then separated from the nutrient bath, purified, and made into its sodium
salt, monosodium glutamate.
Other Sources
Hydrolyzed proteins, or protein hydrolysates, are acid- or enzymatically treated proteins from
certain foods. They contain salts of free amino acids, such as glutamate, at levels of 5 to 20
percent. Hydrolyzed proteins are used in the same manner as MSG in many foods, such as

21. canned vegetables, soups, and processed meats. Another source of MSG is fruits, vegetables and
nuts that have been sprayed with Auxigro, a growth enhancer that contains 30% glutamic acid.
Glutamate is present in a variety of protein-rich foods, and particularly abundant in aged cheese.
How was MSG Discovered?
Despite its ubiquity in common food products, the flavour contributions made by glutamate and
other amino acids were only scientifically identified early in the twentieth century. In 1907,
Japanese researcher Kikunae Ikeda of the Tokyo Imperial University identified brown crystals
left behind after the evaporation of a large amount of kombu broth as glutamic acid. These
crystals, when tasted, reproduced the ineffable but undeniable flavour he detected in many foods,
most especially in seaweed. Professor Ikeda termed this flavour "umami." He then patented a
method of mass-producing a crystalline form of glutamic acid, MSG.
Commercialization
The Ajinomoto company was formed to manufacture and market MSG in Japan; the name
'Ajinomoto' means "essence of taste". It was introduced to the United States in 1947 as Ac'cent
flavor enhancer. Modern commercial MSG is produced by fermentation of starch, sugar beets,
sugar cane, or molasses. About 1.5 million metric tons were sold in 2001, with 4% annual
growth expected. MSG is used commercially as a flavour enhancer, and is added as an ingredient
to many snack foods, frozen dinners, and instant meals such as the seasoning mixtures for instant
noodles.
Scientific review
In 1959, FDA classified MSG as a "generally recognized as safe", or GRAS, substance. This
action stemmed from the 1958 Food Additives Amendment to the Federal Food, Drug, and
Cosmetic Act, which required premarket approval for new food additives and led FDA to
promulgate regulations listing substances, such as MSG, which have a history of safe use or are
otherwise GRAS. Since 1970, FDA has sponsored extensive reviews on the safety of MSG, other
glutamates and hydrolyzed proteins, as part of an ongoing review of safety data on GRAS
substances used in processed foods. One such review was by the Federation of American

22. Societies for Experimental Biology (FASEB) Select Committee on GRAS Substances. In 1980,
the committee concluded that MSG was safe at current levels of use but recommended additional
evaluation to determine MSG's safety at significantly higher levels of consumption. Additional
reports attempted to look at this. In 1986, FDA's Advisory Committee on Hypersensitivity to
Food Constituents concluded that MSG poses no threat to the general public but that reactions of
brief duration might occur in some people. Other reports gave similar findings:
A 1991 report by the European Community's (EC) Scientific Committee for Foods reaffirmed
MSG's safety and classified its "acceptable daily intake" as "not specified", the most favorable
designation for a food ingredient. In addition, the EC Committee said, "Infants, including
prematures, have been shown to metabolize glutamate as efficiently as adults and therefore do
not display any special susceptibility to elevated oral intakes of glutamate." A 1992 report from
the Council on Scientific Affairs of the American Medical Association stated that glutamate in
any form has not been shown to be a "significant health hazard". Also, the 1987 Joint Expert
Committee on Food Additives of the United Nations Food and Agriculture Organization and the
World Health Organization have placed MSG in the safest category of food ingredients.
Scientific knowledge about how the body metabolizes glutamate developed rapidly during the
1980s. Studies showed that glutamate in the body plays an important role in normal functioning
of the nervous system. Questions then arose on the role glutamate in food plays in these
functions and whether or not glutamate in food contributes to certain neurological diseases.
MSG intolerance
There have been numerous studies of allergies and/or sensitivities to MSG, attributed to the free
glutamic acid component, which has been blamed for causing a wide variety of physical
symptoms such as migraines, nausea, digestive upsets, bad dreams, disturbed sleep, drowsiness,
heart palpitations, hair loss, asthma, anaphylactic shock, rapidly increasing diabetes, and many
other complaints. "Chinese restaurant syndrome" is often used as an example of the symptoms
purported to be caused by MSG. Prompted by continuing public interest and a flurry of
glutamate-related studies in the late 1980s, FDA contracted with FASEB in 1992 to review the
available scientific data. The agency asked FASEB to address 18 questions dealing with: the

23. possible role of MSG in eliciting MSG symptom complex the possible role of dietary glutamates
in forming brain lesions and damaging nerve cells in humans underlying conditions that may
predispose a person to adverse effects from MSG the amount consumed and other factors that
may affect a person's response to MSG the quality of scientific data and previous safety reviews.
FASEB held a two-day meeting and convened an expert panel that thoroughly reviewed all the
available scientific literature on this issue. FASEB completed the final report, over 350 pages
long, and delivered it to FDA on July 31, 1995. While not a new study, the report offers a new
safety assessment based on the most comprehensive existing evaluation to date of glutamate
safety. Among the report's key findings: An unknown percentage of the population may react to
MSG and develop MSG symptom complex, a condition characterized by one or more of the
following symptoms: burning sensation in the back of the neck, forearms and chest numbness in
the back of the neck, radiating to the arms and back tingling, warmth and weakness in the face,
temples, upper back, neck and arms facial pressure or tightness chest pain headache nausea rapid
heartbeat weak pulse violent dreams bronchospasm (difficulty breathing) in MSG-intolerant
people with asthma drowsiness weakness. In otherwise healthy MSG-intolerant people, the MSG
symptom complex tends to occur within one hour after eating 3 grams or more of MSG on an
empty stomach or without other food. A typical serving of glutamate-treated food contains less
than 0.5 grams of MSG. A reaction is most likely if the MSG is eaten in a large quantity or in a
liquid, such as a clear soup. Severe, poorly controlled asthma may be a predisposing medical
condition for MSG symptom complex. No evidence suggests that dietary MSG or glutamate
contributes to Alzheimer's disease, Huntington's chorea, amyotrophic lateral sclerosis, AIDS
dementia complex, or any other long-term or chronic diseases. No evidence suggests that dietary
MSG causes brain lesions or damages nerve cells in humans, but there is in infant mice. The
level of vitamin B6 in a person's body plays a role in glutamate metabolism, and the possible
impact of marginal B6 intake should be considered in future research.
Ingredient listing
United States Under current FDA regulations, when MSG is added to a food, it must be
identified as "monosodium glutamate" in the label's ingredient list. Each ingredient used to make
a food must be declared by its name in this list.

24. While technically MSG is only one of several forms of free glutamate used in foods, consumers
frequently use the term MSG to mean all free glutamate. The free glutamic acid component of
MSG may also be present in a wide variety of other additives, including hydrolyzed vegetable
proteins, hydrolyzed yeast, soy extracts, and "natural flavorings".
For this reason, FDA considers labels such as "No MSG" or "No Added MSG" to be misleading
if the food contains ingredients that are sources of free glutamates, such as hydrolyzed protein.
In 1993, FDA proposed adding the phrase "(contains glutamate)" to the common or usual names
of certain protein hydrolysates that contain substantial amounts of glutamate. For example, if the
proposal were adopted, hydrolyzed soy protein would have to be declared on food labels as
"hydrolyzed soy protein (contains glutamate)." However, if FDA issues a new proposal, it would
probably supersede this 1993 one. In 1994, FDA received a citizen's petition requesting changes
in labeling requirements for foods that contain MSG or related substances. The petition asks for
mandatory listing of MSG as an ingredient on labels of manufactured and processed foods that
contain manufactured free glutamic acid. It further asks that the amount of free glutamic acid or
MSG in such products be stated on the label, along with a warning that MSG may be harmful to
certain groups of people. FDA has not yet taken action on the petition.
1.6 What is MolecularGastronomy?
With changes in how we cook and eat, the fields of culinary arts and culinary science appear now
to be merging into one. Many famous restaurant now have cooking laboratories on their
premises, while universities and colleges around the country are beginning to offer degrees in
culinology (a degree program that blends food science and technology with culinary art).
Interest in food science has grown in recent years because of the increasing awareness of the
vital role of food in the health, well-being, and economic status of individuals and nations and
people's curiosity and desire to try new and innovative food dishes. Food science is the study of
the chemical composition of food and food ingredients; their physical, biological and
biochemical properties and and the interaction of food constituents with each other and their
environment.

25. What is Molecular Gastronomy?
Molecular Gastronomy is the application of scientific principles to the understanding and
improvement of small scale food preparation. The term was invented by the Hungarian physicist
Nicholas Kurti in a 1969 presentation to the Royal Institution called "The Physicist in the
kitchen", and popularized by his collaborator the French scientist Hervé This.
Heston Blumenthal, 38, is presently at the forefront of this radical style of cooking (molecular
gastronomy). His triple Michelin starred restaurant The Fat Duck serves dishes like sardine-
flavored sorbet, pasta made out of Jello, snail porridge, or a puree of mango and Douglas fir. At
El Bulli, the restaurant of Ferran Adria in Spain another molecular gastronomist dishes consist of
monkfish liver with tomato seeds and citrus or barnacles with tea foam, or a parmesan cheese ice
cream. During the six months his restaurant is closed, Adrià works on new recipes in a laboratory
near the Barcelona market. Some of the famous restaurant such as Arzak in San Sebastián, Spain,
Upstairs from the restaurant you will find a small food laboratory with pH meters, sonicators and
liquid nitrogen.
Some of the Molecular Gastonomy Experimental Chefs and restaurants are;
 The Fat Duck (Heston Blumenthal) - UK
 Pierre Gagnaire (Pierre Gagnaire) - France
 El Bulli (Ferran Adria) - Spain
 Grand Hotel Villa Serbellione (Ettore Bocchia) - Italy
 Saint Pierre (Emmanuel Stroobant) - Singapore
 Juan Mari Arzak, San Sebastian - Spain
 Chef Thomas Keller, whose French Laundry (California)

26. Summary
 Food and beverage without question is a key component of the hospitality experience.
 Food service establishments are a dominant player in the in any country’s economy.
 This session highlighted great variety in establishments and segments within commercial
and non-commercial food service.
 These different segments provide unique experiences for customers and guests, and they
offer a wealth of career options for those seeking a career in food and beverages.
Learning Outcomes
After completing this session you should be able to:
 identify how science plays a major role in food and nutrition
 identify the types of food types with tastes
 describe how food is digested in a human body
 explain about food flavours and Molecular Gastronomy as the application of scientific
principles to the understanding and improvement of small scale food preparation.
Review Questions
1. What are 4 basic food types and explain briefly?
2. What are the basic tastes in food?
3. Describe food digestive system.
4. What are the flavors in food?
5. Explain the role of MSG in foods.
6. What is Molecular Gastronomy in cookery?

27. References:
https://www.fns.usda.gov/
Culinary Reactions: The Everyday Chemistry of Cooking
Publisher: Chicago Review Press;
Illustrated edition November 1, 2011
ISBN-13 : 978-156976706
Food Commodities
by Bernard Davis
Published by Butterworth-Heinemann
ISBN-13 : 978-0434903061
April,2017