1. Food Chemistry
April 28, 2023admin
What is Food Chemistry?
According to the major classes of According to the major classes of food
constituentshttps: proteins and enzymes, lipids, carbohydrates, vitamins,
flavours and colourants, minerals the micro components, :proteins and
enzymes, lipids, carbohydrates, vitamins, flavours and colourants, minerals
and other micro components, additives and pollutants, the information related
to the topic of food chemistry is broken down into chapters.
Food chemistry, as its name suggests, is the area of chemistry that examines
the biochemistry of food, including its characteristics and how they are
metabolised by the body. It entails the investigation of several chemical
elements, including proteins, carbohydrates, and more. In food chemistry, we
discover strategies to improve food quality as well as how various processing
methods influence various food types.

2. History of food chemistry
A focus on agricultural chemistry emerged in the writings of J. G. Wallerius,
Humphry Davy, and others, leading to the development of the scientific
approach to food and nutrition. For instance, Elements of Agricultural
Chemistry, by Davy, was published in the United Kingdom in 1813 as part of a
course of lectures for the Board of Agriculture and is now in its sixth edition.
Carl Wilhelm Scheele’s 1785 isolation of malic acid from apples was among
earlier research.
Eben Horsford of Lowell, Massachusetts, translated and published some of
Liebig’s studies on the chemistry of food in 1848.
The Society of Public Analysts was established in 1874 with the intention of
using analytical techniques for the general public’s benefit. It was also
motivated by worries about the quality of the food supply, particularly
difficulties with food adulteration and contamination, which by the 1950s had
progressed beyond purposeful contamination to include chemical food
additives. Food chemistry would emerge with the growth of schools and
institutions across the world, most notably in the United States, along with
dietary ingredient research, most notably the Single-grain experiment from
1907 to 1911. The United States Food and Drug Administration was
established in 1906 as a result of more study conducted by Harvey W. Wiley
at the United States Department of Agriculture in the late 19th century. The
Agricultural and Food Chemistry Division of the American Chemical Society
was founded in 1908, and the Institute of Food Technologists was founded in
1909.
Food physical chemistry serves as a foundation for food chemistry because it
frequently draws from rheology, theories of transport phenomena, physical
and chemical thermodynamics, chemical bonds and interaction forces,
quantum mechanics, reaction kinetics, biopolymer science, colloidal
interactions, nucleation, glass transitions, and freezing/disordered or
noncrystalline solids.
Major Food Components:
1) Water Structure
All living creatures include large amounts of water, which is why practically all
meals do as well. Despite adding no calories to the diet, it is necessary for life.
The texture of food is considerably influenced by water. It impacts the sense
of the softness of meat as well as giving fruits and vegetables a crisp texture

3. or turgor. Keep water out of such goods to retain quality. For some food
products, such potato chips, salt, or sugar, lack of water is a crucial
component of their quality.
Thus, preserving food by freezing, dehydration, or concentration lengthens its
shelf life and prevents bacterial development. The ability of water to dissolve
tiny molecules into real solutions and disperse bigger molecules into colloidal
solutions makes it an essential solvent or dispersing medium.
Water is important for many chemical processes that are catalysed by
enzymes, including the hydrolysis of substances like sugars, where acids and
bases ionise. In addition, it serves as a heating, cooling, and cleaning agent. It
is crucial to understand some of water’s distinctive qualities since it serves so
many tasks that are crucial to a food scientist.
2) Protein Structure:

4. Since they account for 50% or more of a cell’s dry weight, proteins are the
most prevalent molecules in a cell. Each protein performs a specific function
in a living cell because of its distinct structure, conformation, or shape.
Proteins play a crucial role as blood system carriers and make up the intricate
muscle system and connective tissue network.
Enzymes are proteins first and foremost, and they play a crucial role as
catalysts in numerous food reactions. Nitrogen, oxygen, hydrogen, and carbon
are components of every protein. The majority of proteins contain sulphur, and
some of them also include other substances. For instance, milk proteins
contain phosphorus, and haemoglobin and myoglobin both contain iron. Some
proteins also contain copper and zinc as ingredients. Amino acids comprise
proteins.
At least 20 distinct amino acids may be found in nature, and depending on
their makeup and structure, they each have unique capabilities. Protein
molecules can undergo significant alterations in response to even little
modifications, such a change in pH or even heating food. Such alterations can
be observed while making cottage cheese from milk that has acid added to it
or making scrambled eggs from eggs that have been heated and stirred.
Proteins are crucial components of food, both nutritionally and practically
speaking. Around 4 kilocalories of energy per gramme may be found in

5. proteins. They have a significant impact on how a food’s texture is
determined. They are intricate molecules, thus it’s crucial to comprehend the
fundamentals of protein structure in order to comprehend the behaviour of
many of them.
For example, strong flour with a high protein content is needed to make bread,
therefore the quantity and type of protein in flour impacts its eligibility for
usage in various products. Examples of food items that employ the functional
characteristics of protein include meringue, cheese, bread, and jelly. Lean
meats, fish, and poultry, as well as beans, tofu, lentils, and other legumes,
grains, including bread and pasta, nuts, and seeds, are examples of common
protein-rich foods.
Protein Requirements:
The amount of protein a child needs depends on their age and weight. For
instance, a typical preschooler aged 4-6 years old needs around 22 grammes
of protein daily, and a child aged 7 to 10 years old needs about 28 grammes.
Protein Fortified Foods:
In addition to eating a lot of naturally occurring protein-rich meals, we may
also purchase protein supplements like drink mixes enriched with protein,
such PediaSure or Carnation quick breakfast. There are several foods that
can contain multiple sources of protein, such a cheeseburger, which combines
meat, cheese, and a bun.
Other examples of meals with added protein are tuna fish sandwiches,
cheeseburgers, pizza, grilled cheese sandwiches, peanut butter and jelly
sandwiches, macaroni and cheese sandwiches, etc. Fruits, beans, and
vegetables all make excellent sources of protein.
Essential Amino Acids in Foods:
The smallest building block of proteins, amino acids are described as organic
molecules with amine and carboxylic acid functional groups. Amino acids are
made up of molecules of nitrogen, carbon, oxygen, and hydrogen. Essential
amino acids, often referred to as limiting amino acids, are those that human
bodies are unable to synthesise and must therefore be taken from dietary
sources.
There are 8 essential amino acids:
1. Tryptophan,

6. 2. Tyrosine,
3. Valine,
4. Leucine,
5. Isoleucine,
6. Lysine,
7. Methionine, and
8. Phenylalanine.
Functions of Essential Amino Acids:
A number of metabolisms can benefit from the inclusion of amino acids. They
are a component of intricate biological systems and processes. An amino
acid’s use and function depend on other amino acids, minerals,
carbohydrates, and fatty acids, and it has indirect effects that show up in a
variety of metabolisms.
Non-Essential Amino Acids in Foods:
Amino acids that are non-essential can be produced by human bodies.
Although they serve the same purposes and serve our bodies in a similar
manner to limiting amino acids, the difference is that those amino acids may
be obtained through our food. The remaining 12 amino acids are classified as
non-essential amino acids and include compounds like alanine, cysteine,
glutamine, glycine, histidine, threonine, asparagine, and proline.
3) Carbohydrates Structure:
Carbon, hydrogen, and oxygen are the three elements that make up
carbohydrates, which can be either simple or complex molecules. Simple
sugars, dextrins, starches, cellulose, hemicellulose, pectins, and gums are
some of the significant dietary carbohydrates. Due to their practical qualities,
they serve as major sources of fibre or energy in the diet and are also vital
dietary ingredients.

7. Our diet contains carbs from plant-based sources. Because they are
essentially carbon hydrates, carbohydrates have that name. They are
specifically made of carbon and water and have the chemical formula Cn(H2n
O). Monosaccharides, sometimes referred to as sugars, are the most basic
kind of carbohydrates and contain the general formula CnH2nOt. The majority
of them have six carbon atoms. Trisaccharides have three sugar units,
oligosaccharides have many units, disaccharides have two units,
trisaccharides have three, and polysaccharides are complex polymers with up
to thousands of units linked together to create a molecule. Each one of these
molecules is a complex carbohydrate polymer with unique characteristics that
are influenced by the type of sugar units that make up the molecule, the type
of glycosidic connections, and the degree of branching. A plant polymer called
starch is kept in the roots and seeds of plants. It gives people energy (4 kcal
per gramme) and is hydrolyzed to glucose, which supplies the glucose
required for the proper operation of the brain and central nervous system.
Long-chain glucose polymers are present in starch grains, which are insoluble
in water. When starch granules are agitated in water, they temporarily
suspend rather than forming a real solution like the smaller salt and sugar
molecules do. When starch is boiled, the swelling becomes permanent, and
the starch starts to seep out. This quality of starch granules makes it possible
to employ starch as a thickening.

8. Carbohydrates perform several functions in food:
 It can be employed as thickeners, stabilisers, gelling agents, and fat
replacements, to name a few .
 influencing texture (gluten, starch).
 Water absorption due to hygroscopic nature.
 Offering a source of food for yeast.
 regulating the dispersion of protein or starch molecules during pectin
gelation.
 Preventing deterioration.
 Postponing protein coagulation.
 Crystals provide structure.
 Affecting osmosis .
 Changing the fruit’s colour.
 viscosity and structure have an impact on texture.
 Adding flavours outside sweetness.
Sources of Starches:
Cereal grains like wheat, maize, or rice are the most significant sources of
starches. While cornflour creates clearer combinations like gravies or sauces,
wheat results in a thick, muddy mixture. Potatoes, vegetables, roots, and
tubers, such as cassava’s root, are regularly utilised to prepare gluten-free
dishes. Legumes like soy beans are another source of starch. In tropical Asia,
the stems and trunks of the sago palm are used to make sago, a powdered
starch. Starch may also be found in fruits. The banana is one illustration.
Gums:
Thousands of monosaccharide units make up the complex hydrophilic
carbohydrates that make up gums. The most prevalent monosaccharide in
gums is galactose; glucose is typically missing. Due to their size and affinity
for water, gums are frequently referred to as hydrocolloids; when combined
with water, they produce stable aqueous colloidal dispersions or sols. Due to
the extremely branched nature of the molecules, most gums are unable to gel.
As a result, they are able to bind or trap vast volumes of water within of their
branches. Gums are categorised as soluble fibre since the body does not fully
digest and absorb them. Therefore, compared to digestible carbs like starch,
they contribute comparatively few calories to the diet.
Main Characteristics of Gums:

9. The two most crucial features of gum are its size and galactose content. Gum
is a huge, highly branching hydrophilic polymer. It produces viscous liquids
and is frequently referred to as hydrocolloids. The majority of gums don’t gel.
Sources of Gum:
Salad dressings, sauces, soups, yoghurt, canned evaporated milk, ice cream,
and other dairy items, as well as baked goods, meat products, and fried
dishes, all frequently include gums. They replace starch as thickening agents
in food goods.
Additionally, they help stabilise emulsions and preserve the creamy texture of
ice cream and other frozen sweets. They are frequently included in goods with
decreased fat because they can boost viscosity and take the place of the fat’s
contribution to texture and mouth feel.
Classification of Gums:
Gums are sourced from plants and fall into five categories: microbial
exudates, seaweed extracts, synthetic gums made from cellulose, and seed
gums and plant exudates.
 Guar gum and locust bean gum, which are seed gums
 Plant exudates, including gum tragacanth and gum arabic
 Xanthan, gellan, and dextran, microbial exudates
 Seaweed polysaccharides, including agar, alginates, and carrageenan
Functional Roles of Gums in Food Technology:
Gums can serve a variety of purposes in food items.
They are listed below:
 Thickeners: condiments, soups, sauces, and salad dressings
 Ice cream, frosting, and emulsified product stabilisers
 Candy: Control crystal size
 Salad dressings as suspending agents
 Fruit bits and cheese analogues as gelling agents
 Coating agents and deep-fried food batters
 Fat substitutes, including low-fat ice cream, sweets, and salad dressings
 Starch substitutes for baked goods, sauces, and soups
 Fillers: low-fat meals, and
 Beverages, soups, and baked items are sources of fibre.

10. Mucilages:
Another soluble fibre found in some foods is mucilage. It is an
exopolysaccharide, a kind of polymer found in several plant-based diets. It is a
naturally occurring, organic plant product with a large molecular weight
(200,000 and higher), but its precise structure is unclear. Galactose,
mannose, and other monosaccharides are found in mucilages, while
galactose, glucuronic acid, and other monosaccharides are found in gums.
Mucilage shares many chemical similarities with gums and pectins but has
certain unique physical characteristics. It is found in diverse locations in
almost all plant types, often in negligible amounts, and is commonly combined
with other compounds like tannins and alkaloids.
Uses of Mucilages:
Although edible, mucilage has a somewhat bland flavour. Due to its
demulcent qualities, it is utilised in medicine. Since the mucilaginous root of
the marshmallow plant has a demulcent quality, the extract used to make
traditional marshmallows also served as a cough suppressant. It serves as a
kind of paper adhesive.
In Sweden, a dairy product called filmjolk is traditionally produced using some
carnivorous plants that include mucilage. Specific enzymes interact with
soybean sugars during the fermentation of natto soyabean to create mucilage.
The volume and viscosity of the mucilage are significant natto properties that
help to create the distinct flavour and aroma of natto.
4. Lipids Structure:
“The framework for the construction and operation of living cells is made up of
lipids, which are organic molecules with hydrogen, carbon, and oxygen
atoms.”
What are Lipids?
Since water is a polar molecule, these organic compounds are nonpolar
molecules that can only dissolve in nonpolar solvents. These molecules,
which are present in meals like oil, butter, whole milk, cheese, fried dishes, as
well as some red meats, can be produced by the liver in the human body.
Properties of Lipids

11. Fats and oils make up the family of organic substances known as lipids.
These molecules produce a lot of energy and are in charge of several bodily
processes. The following list includes some crucial properties of lipids.
 Lipids are fatty or oily nonpolar molecules that are kept in the body’s
adipose tissue.
 A diverse class of substances known as lipids is mostly made up of
hydrocarbon chains.
 Lipids are organic compounds that are high in energy and supply that
energy for several living activities.
 A family of chemicals known as lipids is distinguished by its solubility in
nonpolar solvents and insolubility in water.
 Lipids play an important role in biological systems because they create
the cell membrane, a mechanical barrier that separates a cell from its
surroundings.
Lipid Structure
Classification of Lipids
There are two major categories into which lipids fall:
 Unsaponifiable lipids

12.  Saponificable lipids
Nonsaponifiable Lipids
Hydrolysis cannot break down a nonsaponifiable lipid into smaller molecules.
Lipids that cannot be saponified include prostaglandins, cholesterol, etc.
Saponifiable Lipids
Wax, triglycerides, sphingolipids, and phospholipids are examples of
saponifiable lipids, which may be hydrolyzed in the presence of a base, acid,
or enzymes because they contain one or more ester groups.
These groups can also be separated into polar and non-polar lipids.
Triglycerides, a kind of nonpolar lipid, are used as fuel for energy storage.
Membranes use polar lipids that might create a barrier with an external
aqueous environment. Sphingolipids and glycerophospholipids are two types
of polar lipids.
The key building blocks of all these lipids are fatty acids.
Examples of Lipids
Lipids come in a variety of varieties. Butter, ghee, vegetable oil, cheese,
cholesterol and other steroids, waxes, phospholipids, and fat-soluble vitamins
are a few examples of lipids. These chemicals all share characteristics in
common, such as being insoluble in water and soluble in organic solvents.
Reference
 https://www.sciencedirect.com/journal/food-chemistry
 https://en.wikipedia.org/wiki/Food_chemistry
 https://pubs.acs.org/journal/jafcau