History of food chemistry
History of food chemistry- DESSY
Food chemistry's history dates back as far as the late 18th century when many famous
chemists were involved in discovering chemicals important in foods, including Carl Wilhelm
Scheele (isolated malic acid from apples in 1785), and Sir Humphry Davy published the first
book on agricultural and food chemistry in 1813 titled Elements of Agricultural Chemistry, in
a Course of Lectures for the Board of Agriculture in the United Kingdom which would serve
as a foundation for the profession worldwide, going into a fifth edition.
In 1874 the Society of Public Analysts was formed, with the aim of applying analytical
methods to the benefit of the public.[3] Its early experiments were based on bread, milk and
wine.
It was also out of concern for the quality of the food supply, mainly food adulteration and
contamination issues that would first stem from intentional contamination to later with
chemical food additives by the 1950s. The development of colleges and universities
worldwide, most notably in the United States, would expand food chemistry as well with
research of the dietary substances, most notably the Single-grain experiment during 1907-11.
Additional research by Harvey W. Wiley at the United States Department of Agriculture
during the late 19th century would play a key factor in the creation of the United States Food
and Drug Administration in 1906. The American Chemical Society would establish their
Agricultural and Food Chemistry Division in 1908 while the Institute of Food Technologists
would establish their Food Chemistry Division in 1995.
Food chemistry concepts are often drawn from rheology, theories of transport phenomena,
physical and chemical thermodynamics, chemical bonds and interaction forces, quantum
mechanics and reaction kinetics, biopolymer science, colloidal interactions, nucleation, glass
transitions and freezing/disordered or noncrystalline solids, and thus has Food Physical
Chemistry as a foundation area.[4][5]
Water- DESSY
From Wikipedia, the free encyclopedia
"H2O" and "HOH" redirect here. For other uses, see H2O (disambiguation) and HOH
(disambiguation).
This article is about general aspects of water. For a detailed discussion of its physical and chemical
properties, see Properties of water. For other uses, see Water (disambiguation).
Water in three states: liquid, solid (ice), and gas (invisible water vapor in the air). Clouds are
accumulations of water droplets, condensed from vapor-saturated air.
Play media
Video demonstrating states of water present in domestic life.
Water is a transparent fluid which forms the world's streams, lakes, oceans and rain, and is
the major constituent of the fluids of living things. As a chemical compound, a water
molecule contains one oxygen and two hydrogen atoms that are connected by covalent bonds.
Water is a liquid at standard ambient temperature and pressure, but it often co-exists on Earth
with its solid state, ice; and gaseous state, steam (water vapor).
Water covers 71% of the Earth's surface.[1] It is vital for all known forms of life. On Earth,
96.5% of the planet's water is found in seas and oceans, 1.7% in groundwater, 1.7% in
glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water
bodies, and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles
suspended in air), and precipitation.[2][3] Only 2.5% of the Earth's water is freshwater, and
98.8% of that water is in ice and groundwater. Less than 0.3% of all freshwater is in rivers,
lakes, and the atmosphere, and an even smaller amount of the Earth's freshwater (0.003%) is
contained within biological bodies and manufactured products.[2]
Water on Earth moves continually through the water cycle of evaporation and transpiration
(evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.
Evaporation and transpiration contribute to the precipitation over land. Water used in the
production of a good or service is known as virtual water.
Safe drinking water is essential to humans and other lifeforms even though it provides no
calories or organic nutrients. Access to safe drinking water has improved over the last
decades in almost every part of the world, but approximately one billion people still lack
access to safe water and over 2.5 billion lack access to adequate sanitation.[4] There is a clear
correlation between access to safe water and gross domestic product per capita.[5] However,
some observers have estimated that by 2025 more than half of the world population will be
facing water-based vulnerability.[6] A report, issued in November 2009, suggests that by 2030,
in some developing regions of the world, water demand will exceed supply by 50%.[7] Water
plays an important role in the world economy, as it functions as a solvent for a wide variety
of chemical substances and facilitates industrial cooling and transportation. Approximately
70% of the fresh water used by humans goes to agriculture.[8]
Carbohydrate-RYAN
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Lactose is a disaccharide found in milk. It consists of a molecule of D-galactose and a molecule of Dglucose bonded by beta-1-4 glycosidic linkage. It has a formula of C12H22O11.
A carbohydrate is a large biological molecule, or macromolecule, consisting of carbon (C),
hydrogen (H), and oxygen (O) atoms, usually with a hydrogen:oxygen atom ratio of 2:1 (as in
water); in other words, with the empirical formula Cm(H2O)n (where m could be different from
n).[1] Some exceptions exist; for example, deoxyribose, a sugar component of DNA,[2] has the
empirical formula C5H10O4.[3] Carbohydrates are technically hydrates of carbon;[4] structurally it
is more accurate to view them as polyhydroxy aldehydes and ketones.[5]
The term is most common in biochemistry, where it is a synonym of saccharide. The
carbohydrates (saccharides) are divided into four chemical groups: monosaccharides,
disaccharides, oligosaccharides, and polysaccharides. In general, the monosaccharides and
disaccharides, which are smaller (lower molecular weight) carbohydrates, are commonly
referred to as sugars.[6] The word saccharide comes from the Greek word σάκχαρον
(sákkharon), meaning "sugar." While the scientific nomenclature of carbohydrates is
complex, the names of the monosaccharides and disaccharides very often end in the suffix
-ose. For example, grape sugar is the monosaccharide glucose, cane sugar is the disaccharide
sucrose, and milk sugar is the disaccharide lactose (see illustration).
Carbohydrates perform numerous roles in living organisms. Polysaccharides serve for the
storage of energy (e.g., starch and glycogen), and as structural components (e.g., cellulose in
plants and chitin in arthropods). The 5-carbon monosaccharide ribose is an important
component of coenzymes (e.g., ATP, FAD, and NAD) and the backbone of the genetic
molecule known as RNA. The related deoxyribose is a component of DNA. Saccharides and
their derivatives include many other important biomolecules that play key roles in the
immune system, fertilization, preventing pathogenesis, blood clotting, and development.[7]
In food science and in many informal contexts, the term carbohydrate often means any food
that is particularly rich in the complex carbohydrate starch (such as cereals, bread, and pasta)
or simple carbohydrates, such as sugar (found in candy, jams, and desserts).
Lipid-RYAN
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Structures of some common lipids. At the top are cholesterol[1] and oleic acid.[2] The middle structure
is a triglyceride composed of oleoyl, stearoyl, and palmitoyl chains attached to a glycerol backbone.
At the bottom is the common phospholipid, phosphatidylcholine.[3]
Lipids are a group of naturally occurring molecules that include fats, waxes, sterols, fatsoluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides,
triglycerides, phospholipids, and others. The main biological functions of lipids include
storing energy, signaling, and acting as structural components of cell membranes.[4][5] Lipids
have applications in the cosmetic and food industries as well as in nanotechnology.[6]
Lipids may be broadly defined as hydrophobic or amphiphilic small molecules; the
amphiphilic nature of some lipids allows them to form structures such as vesicles,
multilamellar/unilamellar liposomes, or membranes in an aqueous environment. Biological
lipids originate entirely or in part from two distinct types of biochemical subunits or
"building-blocks": ketoacyl and isoprene groups.[4] Using this approach, lipids may be divided
into eight categories: fatty acids, glycerolipids, glycerophospholipids, sphingolipids,
saccharolipids, and polyketides (derived from condensation of ketoacyl subunits); and sterol
lipids and prenol lipids (derived from condensation of isoprene subunits).[4]
Although the term lipid is sometimes used as a synonym for fats, fats are a subgroup of lipids
called triglycerides. Lipids also encompass molecules such as fatty acids and their derivatives
(including tri-, di-, monoglycerides, and phospholipids), as well as other sterol-containing
metabolites such as cholesterol.[7] Although humans and other mammals use various
biosynthetic pathways to both break down and synthesize lipids, some essential lipids cannot
be made this way and must be obtained from the diet.
The chemical formation of pre-biological lipids and their formation into protocells are
considered key steps in models of abiogenesis, the origin of life.
Protein-RYAN
From Wikipedia, the free encyclopedia
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This article is about a class of molecules. For protein as a nutrient, see Protein (nutrient). For other
uses, see Protein (disambiguation).
A representation of the 3D structure of the protein myoglobin showing turquoise alpha helices. This
protein was the first to have its structure solved by X-ray crystallography. Towards the right-center
among the coils, a prosthetic group called a heme group (shown in gray) with a bound oxygen
molecule (red).
Proteins (/ˈproʊˌtiːnz/ or /ˈproʊti.ɨnz/) are large biological molecules, or macromolecules,
consisting of one or more long chains of amino acid residues. Proteins perform a vast array of
functions within living organisms, including catalyzing metabolic reactions, replicating DNA,
responding to stimuli, and transporting molecules from one location to another. Proteins
differ from one another primarily in their sequence of amino acids, which is dictated by the
nucleotide sequence of their genes, and which usually results in folding of the protein into a
specific three-dimensional structure that determines its activity.
A linear chain of amino acid residues is called a polypeptide. A protein contains at least one
long polypeptide. Short polypeptides, containing less than about 20-30 residues, are rarely
considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The
individual amino acid residues are bonded together by peptide bonds and adjacent amino acid
residues. The sequence of amino acid residues in a protein is defined by the sequence of a
gene, which is encoded in the genetic code. In general, the genetic code specifies 20 standard
amino acids; however, in certain organisms the genetic code can include selenocysteine and
—in certain archaea—pyrrolysine. Shortly after or even during synthesis, the residues in a
protein are often chemically modified by posttranslational modification, which alters the
physical and chemical properties, folding, stability, activity, and ultimately, the function of
the proteins. Sometimes proteins have non-peptide groups attached, which can be called
prosthetic groups or cofactors. Proteins can also work together to achieve a particular
function, and they often associate to form stable protein complexes.
Once formed, proteins only exist for a certain period of time and are then degraded and
recycled by the cell's machinery through the process of protein turnover. A protein's lifespan
is measured in terms of its half-life and covers a wide range. They can exist for minutes or
years with an average lifespan of 1–2 days in mammalian cells. Abnormal and or misfolded
proteins are degraded more rapidly either due to being targeted for destruction or due to being
unstable.
Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are
essential parts of organisms and participate in virtually every process within cells. Many
proteins are enzymes that catalyze biochemical reactions and are vital to metabolism.
Proteins also have structural or mechanical functions, such as actin and myosin in muscle and
the proteins in the cytoskeleton, which form a system of scaffolding that maintains cell shape.
Other proteins are important in cell signaling, immune responses, cell adhesion, and the cell
cycle. Proteins are also necessary in animals' diets, since animals cannot synthesize all the
amino acids they need and must obtain essential amino acids from food. Through the process
of digestion, animals break down ingested protein into free amino acids that are then used in
metabolism.
Proteins may be purified from other cellular components using a variety of techniques such as
ultracentrifugation, precipitation, electrophoresis, and chromatography; the advent of genetic
engineering has made possible a number of methods to facilitate purification. Methods
commonly used to study protein structure and function include immunohistochemistry, sitedirected mutagenesis, X-ray crystallography, nuclear magnetic resonance and mass
spectrometry.
Enzyme- ARTYANDI
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"Biocatalyst" redirects here. For the use of natural catalysts in organic chemistry, see Biocatalysis.
Human glyoxalase I. Two zinc ions that are needed for the enzyme to catalyze its reaction are shown
as purple spheres, and an enzyme inhibitor called S-hexylglutathione is shown as a space-filling
model, filling the two active sites.
Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. They are responsible for
thousands of metabolic processes that sustain life.[1][2] Enzymes are highly selective catalysts,
greatly accelerating both the rate and specificity of metabolic chemical reactions, from the
digestion of food to the synthesis of DNA. Most enzymes are proteins, although some
catalytic RNA molecules have been identified. Enzymes adopt a specific three-dimensional
structure, and may employ organic (e.g. biotin) and inorganic (e.g. magnesium ion) cofactors
to assist in catalysis.
Enzymes act by converting starting molecules (substrates) into different molecules
(products). Almost all chemical reactions in a biological cell need enzymes in order to occur
at rates sufficient for life. Since enzymes are selective for their substrates and speed up only a
few reactions from among many possibilities, the set of enzymes made in a cell determines
which metabolic pathways occur in that cell, tissue and organ. Organelles are also
differentially enriched in sets of enzymes to compartmentalise function within the cell.
Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy
(Ea‡). As a result, products are formed faster and reactions reach their equilibrium state more
rapidly. Most enzyme reaction rates are millions of times faster than those of comparable uncatalyzed reactions and some are so fast that they are diffusion limited. As with all catalysts,
enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of
these reactions. However, enzymes do differ from most other catalysts in that they are highly
specific for their substrates. Enzymes are known to catalyze about 4,000 biochemical
reactions.[3] A few RNA molecules called ribozymes also catalyze reactions, with an important
example being some parts of the ribosome.[4][5] Synthetic molecules called artificial enzymes
also display enzyme-like catalysis.[6]
Enzyme activity can be affected by other molecules: decreased by inhibitors or increased by
activators. Many drugs and poisons are enzyme inhibitors. Activity is also affected by
temperature, pressure, chemical environment (e.g., pH), and the concentration of substrate.
Some enzymes are used commercially, for example, in the synthesis of antibiotics. In
addition, some household products use enzymes to speed up biochemical reactions (e.g.,
enzymes in biological washing powders break down protein or fat stains on clothes; enzymes
in meat tenderizers break down proteins into smaller molecules, making the meat easier to
chew). The study of enzymes is called enzymology
Vitamin- ARTYANDI
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A bottle of high potency B-complex vitamin supplement pills.
A vitamin (US /ˈvaɪtəmɪn/ and UK /ˈvɪtəmɪn/) is an organic compound and a vital nutrient
that an organism requires in limited amounts.[1] An organic chemical compound (or related set
of compounds) is called a vitamin when the organism cannot synthesize the compound in
sufficient quantities, and must be obtained through the diet; thus, the term "vitamin" is
conditional upon the circumstances and the particular organism. For example, ascorbic acid
(vitamin C) is a vitamin for humans, but not for most other animal organisms.
Supplementation is important for the treatment of certain health problems, but there is little
evidence of nutritional benefit when used by otherwise healthy people.[2]
By convention, the term vitamin includes neither other essential nutrients, such as dietary
minerals, essential fatty acids, or essential amino acids (which are needed in greater amounts
than vitamins) nor the great number of other nutrients that promote health, and are required
less often to maintain the health of the organism.[3] Thirteen vitamins are universally
recognized at present. Vitamins are classified by their biological and chemical activity, not
their structure. Thus, each "vitamin" refers to a number of vitamer compounds that all show
the biological activity associated with a particular vitamin. Such a set of chemicals is grouped
under an alphabetized vitamin "generic descriptor" title, such as "vitamin A", which includes
the compounds retinal, retinol, and four known carotenoids. Vitamers by definition are
convertible to the active form of the vitamin in the body, and are sometimes inter-convertible
to one another, as well.
Vitamins have diverse biochemical functions. Some, such as vitamin D, have hormone-like
functions as regulators of mineral metabolism, or regulators of cell and tissue growth and
differentiation (such as some forms of vitamin A). Others function as antioxidants (e.g.,
vitamin E and sometimes vitamin C).[4] The largest number of vitamins, the B complex
vitamins, function as precursors for enzyme cofactors, that help enzymes in their work as
catalysts in metabolism. In this role, vitamins may be tightly bound to enzymes as part of
prosthetic groups: For example, biotin is part of enzymes involved in making fatty acids.
They may also be less tightly bound to enzyme catalysts as coenzymes, detachable molecules
that function to carry chemical groups or electrons between molecules. For example, folic
acid may carry methyl, formyl, and methylene groups in the cell. Although these roles in
assisting enzyme-substrate reactions are vitamins' best-known function, the other vitamin
functions are equally important.[5]
Until the mid-1930s, when the first commercial yeast-extract vitamin B complex and semisynthetic vitamin C supplement tablets were sold, vitamins were obtained solely through food
intake, and changes in diet (which, for example, could occur during a particular growing
season) usually greatly altered the types and amounts of vitamins ingested. However,
vitamins have been produced as commodity chemicals and made widely available as
inexpensive semisynthetic and synthetic-source multivitamin dietary and food supplements
and additives, since the middle of the 20th century
Dietary element-ARTYANDI
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Dietary elements (commonly known as dietary minerals or mineral nutrients) are the
chemical elements required by living organisms, other than the four elements carbon,
hydrogen, nitrogen, and oxygen present in common organic molecules. The term "dietary
mineral" is archaic, as the substances it refers to are chemical elements rather than actual
minerals.
Chemical elements in order of abundance in the human body include the seven major dietary
elements calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium.
Important "trace" or minor dietary elements, necessary for mammalian life, include iron,
cobalt, copper, zinc, manganese, molybdenum, iodine, bromine, and selenium (see below for
detailed discussion).
Over twenty dietary elements are necessary for mammals, and several more for various other
types of life. The total number of chemical elements that are absolutely needed is not known
for any organism. Ultratrace amounts of some elements (e.g., boron, chromium) are known to
clearly have a role but the exact biochemical nature is unknown, and others (e.g. arsenic,
silicon) are suspected to have a role in health, but without proof.
Most chemical element that enter into the dietary physiology of organisms are in the form of
simple compounds. Larger chemical compound of elements need to be broken down for
absorption. Plants absorb dissolved elements in soils, which are subsequently picked up by
the herbivores that eat them and so on, the elements move up the food chain. Larger
organisms may also consume soil (geophagia) and visit salt licks to obtain limiting dietary
elements they are unable to acquire through other components of their diet.
Bacteria play an essential role in the weathering of primary elements that results in the
release of nutrients for their own nutrition and for the nutrition of others in the ecological
food chain. One element, cobalt, is available for use by animals only after having been
processed into complicated molecules (e.g., vitamin B12), by bacteria. Scientists are only
recently starting to appreciate the magnitude and role that microorganisms have in the global
cycling and formation of biominerals
Food coloring-REBECCA
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Food coloring spreading on a thin water film in the International Space Station
Food coloring, or color additive, is any dye, pigment or substance that imparts color when it
is added to food or drink. They come in many forms consisting of liquids, powders, gels, and
pastes. Food coloring is used both in commercial food production and in domestic cooking.
Due to its safety and general availability, food coloring is also used in a variety of non-food
applications including cosmetics, pharmaceuticals, home craft projects and medical devices.[1]
Flavor-REBECCA
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This article is about flavor as a sensory impression. For the particle property, see Flavour (particle
physics). For other uses, see Flavor (disambiguation).
This article needs additional citations for verification. Please help improve this article by
adding citations to reliable sources. Unsourced material may be challenged and removed.
(October 2012)
Flavor or flavour (see spelling differences) 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 the mouth and throat as well as
temperature and texture, are also very important to the overall Gestalt of flavor perception.
The flavor of the food, as such, can be altered with natural or artificial flavorants, which
affect these senses.
Flavorant is defined as a substance that gives another substance flavor, altering the
characteristics of the solute, causing it to become sweet, sour, tangy, etc.
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 (savory), pungent or piquant, and
metallic – the seven 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.
Nowhere 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. The flavorings of commercially produced food products
are typically created by flavorists.
Although the terms "flavoring" or "flavorant" 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. Identification of nature-identical flavorants are done using
technology such as headspace techniques
Food additive-SYARIFAH
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Food additives are substances added to food to preserve flavor or enhance its taste and
appearance. Some additives have been used for centuries; for example, preserving food by
pickling (with vinegar), salting, as with bacon, preserving sweets or using sulfur dioxide as
with wines. With the advent of processed foods in the second half of the 20th century, many
more additives have been introduced, of both natural and artificial origin.
Antioxidant-SYARIFAH
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Model of the antioxidant metabolite glutathione. The yellow sphere is the redox-active sulfur atom
that provides antioxidant activity, while the red, blue, white, and dark grey spheres represent oxygen,
nitrogen, hydrogen, and carbon atoms, respectively.
An antioxidant is a molecule that inhibits the oxidation of other molecules. Oxidation is a
chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent.
Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions.
When the chain reaction occurs in a cell, it can cause damage or death to the cell.
Antioxidants terminate these chain reactions by removing free radical intermediates, and
inhibit other oxidation reactions. They do this by being oxidized themselves, so antioxidants
are often reducing agents such as thiols, ascorbic acid, or polyphenols.[1]
Substituted phenols and derivatives of phenylenediamine are common antioxidants used to inhibit
gum formation in gasoline (petrol).
Although oxidation reactions are crucial for life, they can also be damaging; plants and
animals maintain complex systems of multiple types of antioxidants, such as glutathione,
vitamin C, vitamin A, and vitamin E as well as enzymes such as catalase, superoxide
dismutase and various peroxidases. Insufficient levels of antioxidants, or inhibition of the
antioxidant enzymes, cause oxidative stress and may damage or kill cells. Oxidative stress is
damage to cell structure and cell function by overly reactive oxygen-containing molecules
and chronic excessive inflammation. Oxidative stress seems to play a significant role in many
human diseases, including cancers. The use of antioxidants in pharmacology is intensively
studied, particularly as treatments for stroke and neurodegenerative diseases. For these
reasons, oxidative stress can be considered to be both the cause and the consequence of some
diseases.
Antioxidants are widely used in dietary supplements and have been investigated for the
prevention of diseases such as cancer, coronary heart disease and even altitude sickness.[2]
Although initial studies suggested that antioxidant supplements might promote health, later
large clinical trials of antioxidant supplements including beta-carotene, vitamin A, and
vitamin E singly or in different combinations suggest that supplementation has no effect on
mortality or possibly increases it.[3][4][5] Randomized clinical trials of antioxidants including
beta carotene, vitamin E, vitamin C and selenium have shown no effect on cancer risk or
increased cancer risk associated with supplementation.[6][7][8][9][10][11][12] Supplementation with
selenium or vitamin E does not reduce the risk of cardiovascular disease.[13][14]
Antioxidants also have many industrial uses, such as preservatives in food and cosmetics and
to prevent the degradation of rubber and gasoline.[15]
Food chemistry's history dates back as far as the late 18th century when many famous
chemists were involved in discovering chemicals important in foods, including Carl Wilhelm
Scheele (isolated malic acid from apples in 1785), and Sir Humphry Davy published the first
book on agricultural and food chemistry in 1813 titled Elements of Agricultural Chemistry, in
a Course of Lectures for the Board of Agriculture in the United Kingdom which would serve
as a foundation for the profession worldwide, going into a fifth edition.
In 1874 the Society of Public Analysts was formed, with the aim of applying analytical
methods to the benefit of the public.[3] Its early experiments were based on bread, milk and
wine.
It was also out of concern for the quality of the food supply, mainly food adulteration and
contamination issues that would first stem from intentional contamination to later with
chemical food additives by the 1950s. The development of colleges and universities
worldwide, most notably in the United States, would expand food chemistry as well with
research of the dietary substances, most notably the Single-grain experiment during 1907-11.
Additional research by Harvey W. Wiley at the United States Department of Agriculture
during the late 19th century would play a key factor in the creation of the United States Food
and Drug Administration in 1906. The American Chemical Society would establish their
Agricultural and Food Chemistry Division in 1908 while the Institute of Food Technologists
would establish their Food Chemistry Division in 1995.
Food chemistry concepts are often drawn from rheology, theories of transport phenomena,
physical and chemical thermodynamics, chemical bonds and interaction forces, quantum
mechanics and reaction kinetics, biopolymer science, colloidal interactions, nucleation, glass
transitions and freezing/disordered or noncrystalline solids, and thus has Food Physical
Chemistry as a foundation area.[4][5]
Water- DESSY
From Wikipedia, the free encyclopedia
"H2O" and "HOH" redirect here. For other uses, see H2O (disambiguation) and HOH
(disambiguation).
This article is about general aspects of water. For a detailed discussion of its physical and chemical
properties, see Properties of water. For other uses, see Water (disambiguation).
Water in three states: liquid, solid (ice), and gas (invisible water vapor in the air). Clouds are
accumulations of water droplets, condensed from vapor-saturated air.
Play media
Video demonstrating states of water present in domestic life.
Water is a transparent fluid which forms the world's streams, lakes, oceans and rain, and is
the major constituent of the fluids of living things. As a chemical compound, a water
molecule contains one oxygen and two hydrogen atoms that are connected by covalent bonds.
Water is a liquid at standard ambient temperature and pressure, but it often co-exists on Earth
with its solid state, ice; and gaseous state, steam (water vapor).
Water covers 71% of the Earth's surface.[1] It is vital for all known forms of life. On Earth,
96.5% of the planet's water is found in seas and oceans, 1.7% in groundwater, 1.7% in
glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water
bodies, and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles
suspended in air), and precipitation.[2][3] Only 2.5% of the Earth's water is freshwater, and
98.8% of that water is in ice and groundwater. Less than 0.3% of all freshwater is in rivers,
lakes, and the atmosphere, and an even smaller amount of the Earth's freshwater (0.003%) is
contained within biological bodies and manufactured products.[2]
Water on Earth moves continually through the water cycle of evaporation and transpiration
(evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.
Evaporation and transpiration contribute to the precipitation over land. Water used in the
production of a good or service is known as virtual water.
Safe drinking water is essential to humans and other lifeforms even though it provides no
calories or organic nutrients. Access to safe drinking water has improved over the last
decades in almost every part of the world, but approximately one billion people still lack
access to safe water and over 2.5 billion lack access to adequate sanitation.[4] There is a clear
correlation between access to safe water and gross domestic product per capita.[5] However,
some observers have estimated that by 2025 more than half of the world population will be
facing water-based vulnerability.[6] A report, issued in November 2009, suggests that by 2030,
in some developing regions of the world, water demand will exceed supply by 50%.[7] Water
plays an important role in the world economy, as it functions as a solvent for a wide variety
of chemical substances and facilitates industrial cooling and transportation. Approximately
70% of the fresh water used by humans goes to agriculture.[8]
Carbohydrate-RYAN
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Lactose is a disaccharide found in milk. It consists of a molecule of D-galactose and a molecule of Dglucose bonded by beta-1-4 glycosidic linkage. It has a formula of C12H22O11.
A carbohydrate is a large biological molecule, or macromolecule, consisting of carbon (C),
hydrogen (H), and oxygen (O) atoms, usually with a hydrogen:oxygen atom ratio of 2:1 (as in
water); in other words, with the empirical formula Cm(H2O)n (where m could be different from
n).[1] Some exceptions exist; for example, deoxyribose, a sugar component of DNA,[2] has the
empirical formula C5H10O4.[3] Carbohydrates are technically hydrates of carbon;[4] structurally it
is more accurate to view them as polyhydroxy aldehydes and ketones.[5]
The term is most common in biochemistry, where it is a synonym of saccharide. The
carbohydrates (saccharides) are divided into four chemical groups: monosaccharides,
disaccharides, oligosaccharides, and polysaccharides. In general, the monosaccharides and
disaccharides, which are smaller (lower molecular weight) carbohydrates, are commonly
referred to as sugars.[6] The word saccharide comes from the Greek word σάκχαρον
(sákkharon), meaning "sugar." While the scientific nomenclature of carbohydrates is
complex, the names of the monosaccharides and disaccharides very often end in the suffix
-ose. For example, grape sugar is the monosaccharide glucose, cane sugar is the disaccharide
sucrose, and milk sugar is the disaccharide lactose (see illustration).
Carbohydrates perform numerous roles in living organisms. Polysaccharides serve for the
storage of energy (e.g., starch and glycogen), and as structural components (e.g., cellulose in
plants and chitin in arthropods). The 5-carbon monosaccharide ribose is an important
component of coenzymes (e.g., ATP, FAD, and NAD) and the backbone of the genetic
molecule known as RNA. The related deoxyribose is a component of DNA. Saccharides and
their derivatives include many other important biomolecules that play key roles in the
immune system, fertilization, preventing pathogenesis, blood clotting, and development.[7]
In food science and in many informal contexts, the term carbohydrate often means any food
that is particularly rich in the complex carbohydrate starch (such as cereals, bread, and pasta)
or simple carbohydrates, such as sugar (found in candy, jams, and desserts).
Lipid-RYAN
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Structures of some common lipids. At the top are cholesterol[1] and oleic acid.[2] The middle structure
is a triglyceride composed of oleoyl, stearoyl, and palmitoyl chains attached to a glycerol backbone.
At the bottom is the common phospholipid, phosphatidylcholine.[3]
Lipids are a group of naturally occurring molecules that include fats, waxes, sterols, fatsoluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides,
triglycerides, phospholipids, and others. The main biological functions of lipids include
storing energy, signaling, and acting as structural components of cell membranes.[4][5] Lipids
have applications in the cosmetic and food industries as well as in nanotechnology.[6]
Lipids may be broadly defined as hydrophobic or amphiphilic small molecules; the
amphiphilic nature of some lipids allows them to form structures such as vesicles,
multilamellar/unilamellar liposomes, or membranes in an aqueous environment. Biological
lipids originate entirely or in part from two distinct types of biochemical subunits or
"building-blocks": ketoacyl and isoprene groups.[4] Using this approach, lipids may be divided
into eight categories: fatty acids, glycerolipids, glycerophospholipids, sphingolipids,
saccharolipids, and polyketides (derived from condensation of ketoacyl subunits); and sterol
lipids and prenol lipids (derived from condensation of isoprene subunits).[4]
Although the term lipid is sometimes used as a synonym for fats, fats are a subgroup of lipids
called triglycerides. Lipids also encompass molecules such as fatty acids and their derivatives
(including tri-, di-, monoglycerides, and phospholipids), as well as other sterol-containing
metabolites such as cholesterol.[7] Although humans and other mammals use various
biosynthetic pathways to both break down and synthesize lipids, some essential lipids cannot
be made this way and must be obtained from the diet.
The chemical formation of pre-biological lipids and their formation into protocells are
considered key steps in models of abiogenesis, the origin of life.
Protein-RYAN
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This article is about a class of molecules. For protein as a nutrient, see Protein (nutrient). For other
uses, see Protein (disambiguation).
A representation of the 3D structure of the protein myoglobin showing turquoise alpha helices. This
protein was the first to have its structure solved by X-ray crystallography. Towards the right-center
among the coils, a prosthetic group called a heme group (shown in gray) with a bound oxygen
molecule (red).
Proteins (/ˈproʊˌtiːnz/ or /ˈproʊti.ɨnz/) are large biological molecules, or macromolecules,
consisting of one or more long chains of amino acid residues. Proteins perform a vast array of
functions within living organisms, including catalyzing metabolic reactions, replicating DNA,
responding to stimuli, and transporting molecules from one location to another. Proteins
differ from one another primarily in their sequence of amino acids, which is dictated by the
nucleotide sequence of their genes, and which usually results in folding of the protein into a
specific three-dimensional structure that determines its activity.
A linear chain of amino acid residues is called a polypeptide. A protein contains at least one
long polypeptide. Short polypeptides, containing less than about 20-30 residues, are rarely
considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The
individual amino acid residues are bonded together by peptide bonds and adjacent amino acid
residues. The sequence of amino acid residues in a protein is defined by the sequence of a
gene, which is encoded in the genetic code. In general, the genetic code specifies 20 standard
amino acids; however, in certain organisms the genetic code can include selenocysteine and
—in certain archaea—pyrrolysine. Shortly after or even during synthesis, the residues in a
protein are often chemically modified by posttranslational modification, which alters the
physical and chemical properties, folding, stability, activity, and ultimately, the function of
the proteins. Sometimes proteins have non-peptide groups attached, which can be called
prosthetic groups or cofactors. Proteins can also work together to achieve a particular
function, and they often associate to form stable protein complexes.
Once formed, proteins only exist for a certain period of time and are then degraded and
recycled by the cell's machinery through the process of protein turnover. A protein's lifespan
is measured in terms of its half-life and covers a wide range. They can exist for minutes or
years with an average lifespan of 1–2 days in mammalian cells. Abnormal and or misfolded
proteins are degraded more rapidly either due to being targeted for destruction or due to being
unstable.
Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are
essential parts of organisms and participate in virtually every process within cells. Many
proteins are enzymes that catalyze biochemical reactions and are vital to metabolism.
Proteins also have structural or mechanical functions, such as actin and myosin in muscle and
the proteins in the cytoskeleton, which form a system of scaffolding that maintains cell shape.
Other proteins are important in cell signaling, immune responses, cell adhesion, and the cell
cycle. Proteins are also necessary in animals' diets, since animals cannot synthesize all the
amino acids they need and must obtain essential amino acids from food. Through the process
of digestion, animals break down ingested protein into free amino acids that are then used in
metabolism.
Proteins may be purified from other cellular components using a variety of techniques such as
ultracentrifugation, precipitation, electrophoresis, and chromatography; the advent of genetic
engineering has made possible a number of methods to facilitate purification. Methods
commonly used to study protein structure and function include immunohistochemistry, sitedirected mutagenesis, X-ray crystallography, nuclear magnetic resonance and mass
spectrometry.
Enzyme- ARTYANDI
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"Biocatalyst" redirects here. For the use of natural catalysts in organic chemistry, see Biocatalysis.
Human glyoxalase I. Two zinc ions that are needed for the enzyme to catalyze its reaction are shown
as purple spheres, and an enzyme inhibitor called S-hexylglutathione is shown as a space-filling
model, filling the two active sites.
Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. They are responsible for
thousands of metabolic processes that sustain life.[1][2] Enzymes are highly selective catalysts,
greatly accelerating both the rate and specificity of metabolic chemical reactions, from the
digestion of food to the synthesis of DNA. Most enzymes are proteins, although some
catalytic RNA molecules have been identified. Enzymes adopt a specific three-dimensional
structure, and may employ organic (e.g. biotin) and inorganic (e.g. magnesium ion) cofactors
to assist in catalysis.
Enzymes act by converting starting molecules (substrates) into different molecules
(products). Almost all chemical reactions in a biological cell need enzymes in order to occur
at rates sufficient for life. Since enzymes are selective for their substrates and speed up only a
few reactions from among many possibilities, the set of enzymes made in a cell determines
which metabolic pathways occur in that cell, tissue and organ. Organelles are also
differentially enriched in sets of enzymes to compartmentalise function within the cell.
Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy
(Ea‡). As a result, products are formed faster and reactions reach their equilibrium state more
rapidly. Most enzyme reaction rates are millions of times faster than those of comparable uncatalyzed reactions and some are so fast that they are diffusion limited. As with all catalysts,
enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of
these reactions. However, enzymes do differ from most other catalysts in that they are highly
specific for their substrates. Enzymes are known to catalyze about 4,000 biochemical
reactions.[3] A few RNA molecules called ribozymes also catalyze reactions, with an important
example being some parts of the ribosome.[4][5] Synthetic molecules called artificial enzymes
also display enzyme-like catalysis.[6]
Enzyme activity can be affected by other molecules: decreased by inhibitors or increased by
activators. Many drugs and poisons are enzyme inhibitors. Activity is also affected by
temperature, pressure, chemical environment (e.g., pH), and the concentration of substrate.
Some enzymes are used commercially, for example, in the synthesis of antibiotics. In
addition, some household products use enzymes to speed up biochemical reactions (e.g.,
enzymes in biological washing powders break down protein or fat stains on clothes; enzymes
in meat tenderizers break down proteins into smaller molecules, making the meat easier to
chew). The study of enzymes is called enzymology
Vitamin- ARTYANDI
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A bottle of high potency B-complex vitamin supplement pills.
A vitamin (US /ˈvaɪtəmɪn/ and UK /ˈvɪtəmɪn/) is an organic compound and a vital nutrient
that an organism requires in limited amounts.[1] An organic chemical compound (or related set
of compounds) is called a vitamin when the organism cannot synthesize the compound in
sufficient quantities, and must be obtained through the diet; thus, the term "vitamin" is
conditional upon the circumstances and the particular organism. For example, ascorbic acid
(vitamin C) is a vitamin for humans, but not for most other animal organisms.
Supplementation is important for the treatment of certain health problems, but there is little
evidence of nutritional benefit when used by otherwise healthy people.[2]
By convention, the term vitamin includes neither other essential nutrients, such as dietary
minerals, essential fatty acids, or essential amino acids (which are needed in greater amounts
than vitamins) nor the great number of other nutrients that promote health, and are required
less often to maintain the health of the organism.[3] Thirteen vitamins are universally
recognized at present. Vitamins are classified by their biological and chemical activity, not
their structure. Thus, each "vitamin" refers to a number of vitamer compounds that all show
the biological activity associated with a particular vitamin. Such a set of chemicals is grouped
under an alphabetized vitamin "generic descriptor" title, such as "vitamin A", which includes
the compounds retinal, retinol, and four known carotenoids. Vitamers by definition are
convertible to the active form of the vitamin in the body, and are sometimes inter-convertible
to one another, as well.
Vitamins have diverse biochemical functions. Some, such as vitamin D, have hormone-like
functions as regulators of mineral metabolism, or regulators of cell and tissue growth and
differentiation (such as some forms of vitamin A). Others function as antioxidants (e.g.,
vitamin E and sometimes vitamin C).[4] The largest number of vitamins, the B complex
vitamins, function as precursors for enzyme cofactors, that help enzymes in their work as
catalysts in metabolism. In this role, vitamins may be tightly bound to enzymes as part of
prosthetic groups: For example, biotin is part of enzymes involved in making fatty acids.
They may also be less tightly bound to enzyme catalysts as coenzymes, detachable molecules
that function to carry chemical groups or electrons between molecules. For example, folic
acid may carry methyl, formyl, and methylene groups in the cell. Although these roles in
assisting enzyme-substrate reactions are vitamins' best-known function, the other vitamin
functions are equally important.[5]
Until the mid-1930s, when the first commercial yeast-extract vitamin B complex and semisynthetic vitamin C supplement tablets were sold, vitamins were obtained solely through food
intake, and changes in diet (which, for example, could occur during a particular growing
season) usually greatly altered the types and amounts of vitamins ingested. However,
vitamins have been produced as commodity chemicals and made widely available as
inexpensive semisynthetic and synthetic-source multivitamin dietary and food supplements
and additives, since the middle of the 20th century
Dietary element-ARTYANDI
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Dietary elements (commonly known as dietary minerals or mineral nutrients) are the
chemical elements required by living organisms, other than the four elements carbon,
hydrogen, nitrogen, and oxygen present in common organic molecules. The term "dietary
mineral" is archaic, as the substances it refers to are chemical elements rather than actual
minerals.
Chemical elements in order of abundance in the human body include the seven major dietary
elements calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium.
Important "trace" or minor dietary elements, necessary for mammalian life, include iron,
cobalt, copper, zinc, manganese, molybdenum, iodine, bromine, and selenium (see below for
detailed discussion).
Over twenty dietary elements are necessary for mammals, and several more for various other
types of life. The total number of chemical elements that are absolutely needed is not known
for any organism. Ultratrace amounts of some elements (e.g., boron, chromium) are known to
clearly have a role but the exact biochemical nature is unknown, and others (e.g. arsenic,
silicon) are suspected to have a role in health, but without proof.
Most chemical element that enter into the dietary physiology of organisms are in the form of
simple compounds. Larger chemical compound of elements need to be broken down for
absorption. Plants absorb dissolved elements in soils, which are subsequently picked up by
the herbivores that eat them and so on, the elements move up the food chain. Larger
organisms may also consume soil (geophagia) and visit salt licks to obtain limiting dietary
elements they are unable to acquire through other components of their diet.
Bacteria play an essential role in the weathering of primary elements that results in the
release of nutrients for their own nutrition and for the nutrition of others in the ecological
food chain. One element, cobalt, is available for use by animals only after having been
processed into complicated molecules (e.g., vitamin B12), by bacteria. Scientists are only
recently starting to appreciate the magnitude and role that microorganisms have in the global
cycling and formation of biominerals
Food coloring-REBECCA
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Food coloring spreading on a thin water film in the International Space Station
Food coloring, or color additive, is any dye, pigment or substance that imparts color when it
is added to food or drink. They come in many forms consisting of liquids, powders, gels, and
pastes. Food coloring is used both in commercial food production and in domestic cooking.
Due to its safety and general availability, food coloring is also used in a variety of non-food
applications including cosmetics, pharmaceuticals, home craft projects and medical devices.[1]
Flavor-REBECCA
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This article is about flavor as a sensory impression. For the particle property, see Flavour (particle
physics). For other uses, see Flavor (disambiguation).
This article needs additional citations for verification. Please help improve this article by
adding citations to reliable sources. Unsourced material may be challenged and removed.
(October 2012)
Flavor or flavour (see spelling differences) 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 the mouth and throat as well as
temperature and texture, are also very important to the overall Gestalt of flavor perception.
The flavor of the food, as such, can be altered with natural or artificial flavorants, which
affect these senses.
Flavorant is defined as a substance that gives another substance flavor, altering the
characteristics of the solute, causing it to become sweet, sour, tangy, etc.
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 (savory), pungent or piquant, and
metallic – the seven 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.
Nowhere 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. The flavorings of commercially produced food products
are typically created by flavorists.
Although the terms "flavoring" or "flavorant" 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. Identification of nature-identical flavorants are done using
technology such as headspace techniques
Food additive-SYARIFAH
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Food additives are substances added to food to preserve flavor or enhance its taste and
appearance. Some additives have been used for centuries; for example, preserving food by
pickling (with vinegar), salting, as with bacon, preserving sweets or using sulfur dioxide as
with wines. With the advent of processed foods in the second half of the 20th century, many
more additives have been introduced, of both natural and artificial origin.
Antioxidant-SYARIFAH
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Model of the antioxidant metabolite glutathione. The yellow sphere is the redox-active sulfur atom
that provides antioxidant activity, while the red, blue, white, and dark grey spheres represent oxygen,
nitrogen, hydrogen, and carbon atoms, respectively.
An antioxidant is a molecule that inhibits the oxidation of other molecules. Oxidation is a
chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent.
Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions.
When the chain reaction occurs in a cell, it can cause damage or death to the cell.
Antioxidants terminate these chain reactions by removing free radical intermediates, and
inhibit other oxidation reactions. They do this by being oxidized themselves, so antioxidants
are often reducing agents such as thiols, ascorbic acid, or polyphenols.[1]
Substituted phenols and derivatives of phenylenediamine are common antioxidants used to inhibit
gum formation in gasoline (petrol).
Although oxidation reactions are crucial for life, they can also be damaging; plants and
animals maintain complex systems of multiple types of antioxidants, such as glutathione,
vitamin C, vitamin A, and vitamin E as well as enzymes such as catalase, superoxide
dismutase and various peroxidases. Insufficient levels of antioxidants, or inhibition of the
antioxidant enzymes, cause oxidative stress and may damage or kill cells. Oxidative stress is
damage to cell structure and cell function by overly reactive oxygen-containing molecules
and chronic excessive inflammation. Oxidative stress seems to play a significant role in many
human diseases, including cancers. The use of antioxidants in pharmacology is intensively
studied, particularly as treatments for stroke and neurodegenerative diseases. For these
reasons, oxidative stress can be considered to be both the cause and the consequence of some
diseases.
Antioxidants are widely used in dietary supplements and have been investigated for the
prevention of diseases such as cancer, coronary heart disease and even altitude sickness.[2]
Although initial studies suggested that antioxidant supplements might promote health, later
large clinical trials of antioxidant supplements including beta-carotene, vitamin A, and
vitamin E singly or in different combinations suggest that supplementation has no effect on
mortality or possibly increases it.[3][4][5] Randomized clinical trials of antioxidants including
beta carotene, vitamin E, vitamin C and selenium have shown no effect on cancer risk or
increased cancer risk associated with supplementation.[6][7][8][9][10][11][12] Supplementation with
selenium or vitamin E does not reduce the risk of cardiovascular disease.[13][14]
Antioxidants also have many industrial uses, such as preservatives in food and cosmetics and
to prevent the degradation of rubber and gasoline.[15]