Food additives are substances added to food to preserve flavor or enhance its taste, appearance, or other qualities. Some additives have been used for centuries. With the advent of processed foods in the second half of the twentieth century, many more additives have been introduced, of both natural and artificial origin. Food additives include substances that may be introduced to food indirectly in the manufacturing process, through packaging, or during storage or transport. To regulate these additives, inform consumers, each additive is assigned a unique number, termed as "E numbers", used in Europe for all approved additives; this numbering scheme has now been adopted and extended by the Codex Alimentarius Commission to internationally identify all additives, regardless of whether they are approved for use. E numbers are all prefixed by "E", but countries outside Europe use only the number, whether the additive is approved in Europe or not. For example, acetic acid is written as E260 on products sold in Europe, but is known as additive 260 in some countries.
Additive 103, alkannin, is not approved for use in Europe so does not have an E number, although it is approved for use in Australia and New Zealand. Since 1987, Australia has had an approved system of labelling for additives in packaged foods; each food additive has to be numbered. The numbers are the same as in Europe, but without the prefix "E"; the United States Food and Drug Administration lists these items as "generally recognized as safe". See list of food additives for a complete list of all the names. Food additives can be divided into several groups, although there is some overlap because some additives exert more than one effect. For example, salt is both a preservative as well as a flavor. Acidulents Acidulents confer sour or acid taste. Common acidulents include vinegar, citric acid, tartaric acid, malic acid, fumaric acid, lactic acid. Acidity regulators Acidity regulators are used for controlling the pH of foods for stability or to affect activity of enzymes. Anticaking agents Anticaking agents keep powders such as milk powder from sticking.
Antifoaming and foaming agents Antifoaming agents prevent foaming in foods. Foaming agents do the reverse. Antioxidants Antioxidants such as vitamin C are preservatives by inhibiting the degradation of food by oxygen. Bulking agents Bulking agents such as starch are additives that increase the bulk of a food without affecting its taste. Food coloring Colorings are added to food to replace colors lost during preparation or to make food look more attractive. Fortifying agents Vitamins and dietary supplements to increase the nutritional value Color retention agents In contrast to colorings, color retention agents are used to preserve a food's existing color. Emulsifiers Emulsifiers allow water and oils to remain mixed together in an emulsion, as in mayonnaise, ice cream, homogenized milk. Flavors Flavors are additives that give food a particular taste or smell, may be derived from natural ingredients or created artificially. Flavor enhancers Flavor enhancers enhance a food's existing flavors. A popular example is monosodium glutamate.
Some flavor enhancers have their own flavors. Flour treatment agents Flour treatment agents are added to flour to improve its color or its use in baking. Glazing agents Glazing agents provide a shiny appearance or protective coating to foods. Humectants Humectants prevent foods from drying out. Tracer gas Tracer gas allow for package integrity testing to prevent foods from being exposed to atmosphere, thus guaranteeing shelf life. Preservatives Preservatives prevent or inhibit spoilage of food due to fungi and other microorganisms. Stabilizers Stabilizers and gelling agents, like agar or pectin give foods a firmer texture. While they are not true emulsifiers, they help to stabilize emulsions. Sweeteners Sweeteners are added to foods for flavoring. Sweeteners other than sugar are added to keep the food energy low, or because they have beneficial effects regarding diabetes mellitus, tooth decay, or diarrhea. Thickeners Thickening agents are substances which, when added to the mixture, increase its viscosity without modifying its other properties.
Packaging Bisphenols and perfluoroalkyl chemicals are indirect additives used in manufacturing or packaging. In July 2018 the American Academy of Pediatrics called for more careful study of those three substances, along with nitrates and food coloring, as they might harm children during development. With the increasing use of processed foods since the 19th century, food additives are more used. Many countries regulate their use. For example, boric acid was used as a food preservative from the 1870s to the 1920s, but was banned after World War I due to its toxicity, as demonstrated in animal and human studies. During World War II, the urgent need for cheap, available food preservatives led to it being used again, but it was banned in the 1950s; such cases led to a general mistrust of food additives, an application of the precautionary principle led to the conclusion that only additives that are known to be safe should be used in foods. In the United States, this led to the adoption of the Delaney clause, an amendment to the Federal Food and Cosmetic Act of 1938, stating that no carcinogenic substances may be used as food additives.
Tannins are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term tannin refers to the use of oak and other bark in tanning animal hides into leather. By extension, the term tannin is applied to any large polyphenolic compound containing sufficient hydroxyls and other suitable groups to form strong complexes with various macromolecules; the tannin compounds are distributed in many species of plants, where they play a role in protection from predation and might help in regulating plant growth. The astringency from the tannins is what causes the dry and puckery feeling in the mouth following the consumption of unripened fruit, red wine or tea; the destruction or modification of tannins with time plays an important role when determining harvesting times. Tannins have molecular weights ranging from 500 to over 3,000 and up to 20,000. There are three major classes of tannins: Shown below are the base unit or monomer of the tannin.
In the flavone-derived tannins, the base shown must be hydroxylated and polymerized in order to give the high molecular weight polyphenol motif that characterizes tannins. Tannin molecules require at least 12 hydroxyl groups and at least five phenyl groups to function as protein binders. Oligostilbenoids constitute a class of tannins. Pseudo tannins are low molecular weight compounds associated with other compounds, they do not change color during the Goldbeater's skin test, unlike hydrolysable and condensed tannins, cannot be used as tanning compounds. Some examples of pseudo tannins and their sources are: Ellagic acid, gallic acid, pyrogallic acid were first discovered by chemist Henri Braconnot in 1831. Julius Löwe was the first person to synthesize ellagic acid by heating gallic acid with arsenic acid or silver oxide. Maximilian Nierenstein studied natural tannins found in different plant species. Working with Arthur George Perkin, he prepared ellagic acid from algarobilla and certain other fruits in 1905.
He suggested its formation from galloyl-glycine by Penicillium in 1915. Tannase is an enzyme, he proved the presence of catechin in cocoa beans in 1931. He showed in 1945 that luteic acid, a molecule present in the myrobalanitannin, a tannin found in the fruit of Terminalia chebula, is an intermediary compound in the synthesis of ellagic acid. At these times, molecule formulas were determined through combustion analysis; the discovery in 1943 by Martin and Synge of paper chromatography provided for the first time the means of surveying the phenolic constituents of plants and for their separation and identification. There was an explosion of activity in this field after 1945, including prominent work by Edgar Charles Bate-Smith and Tony Swain at Cambridge University. In 1966, Edwin Haslam proposed a first comprehensive definition of plant polyphenols based on the earlier proposals of Bate-Smith and Theodore White, which includes specific structural characteristics common to all phenolics having a tanning property.
It is referred to as the White–Bate-Smith–Swain–Haslam definition. Tannins are distributed in species throughout the plant kingdom, they are found in both gymnosperms as well as angiosperms. Mole studied the distribution of tannin in 180 families of dicotyledons and 44 families of monocotyledons. Most families of dicot contain tannin-free species; the best known families of which all species tested contain tannin are: Aceraceae, Anacardiaceae, Burseraceae, Dipterocarpaceae, Grossulariaceae, Myricaceae for dicot and Najadaceae and Typhaceae in Monocot. To the family of the oak, Fagaceae, 73% of the species tested contain tannin. For those of acacias, only 39% of the species tested contain tannin, among Solanaceae rate drops to 6% and 4% for the Asteraceae; some families like the Boraginaceae, Papaveraceae contain no tannin-rich species. The most abundant polyphenols are the condensed tannins, found in all families of plants, comprising up to 50% of the dry weight of leaves. Tannins of tropical woods tend to be of a cathetic nature rather than of the gallic type present in temperate woods.
There may be a loss in the bio-availability of still other tannins in plants due to birds and other pathogens. Tannins are found in leaf, seed and stem tissues. An example of the location of the tannins in stem tissue is that they are found in the growth areas of trees, such as the secondary phloem and xylem and the layer between the cortex and epidermis. Tannins may help regulate the growth of these tissues. In all vascular plants studied so far, tannins are manufactured by a chloroplast-derived organelle, the tannosome. Tannins are physically located in the vacuoles or surface wax of plants; these storage sites keep tannins active against plant predators, but keep some tannins from affecting plant metabolism while the plant tissue is alive. Tannins are classified as ergastic substances, i.e. non-protoplasm materials found in cells. Tannins, by definition, precipitate proteins. In this condition, they must be stored in organelles able to withstand the protein precipitation process. Idioblasts are isolated plant cells which differ from neighbo
Simplified molecular-input line-entry system
The simplified molecular-input line-entry system is a specification in the form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules; the original SMILES specification was initiated in the 1980s. It has since been extended. In 2007, an open standard called. Other linear notations include the Wiswesser line notation, ROSDAL, SYBYL Line Notation; the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. Acknowledged for their parts in the early development were "Gilman Veith and Rose Russo and Albert Leo and Corwin Hansch for supporting the work, Arthur Weininger and Jeremy Scofield for assistance in programming the system." The Environmental Protection Agency funded the initial project to develop SMILES. It has since been modified and extended by others, most notably by Daylight Chemical Information Systems.
In 2007, an open standard called "OpenSMILES" was developed by the Blue Obelisk open-source chemistry community. Other'linear' notations include the Wiswesser Line Notation, ROSDAL and SLN. In July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is considered to have the advantage of being more human-readable than InChI; the term SMILES refers to a line notation for encoding molecular structures and specific instances should be called SMILES strings. However, the term SMILES is commonly used to refer to both a single SMILES string and a number of SMILES strings; the terms "canonical" and "isomeric" can lead to some confusion when applied to SMILES. The terms are not mutually exclusive. A number of valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol. Algorithms have been developed to generate the same SMILES string for a given molecule; this SMILES is unique for each structure, although dependent on the canonicalization algorithm used to generate it, is termed the canonical SMILES.
These algorithms first convert the SMILES to an internal representation of the molecular structure. Various algorithms for generating canonical SMILES have been developed and include those by Daylight Chemical Information Systems, OpenEye Scientific Software, MEDIT, Chemical Computing Group, MolSoft LLC, the Chemistry Development Kit. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database; the original paper that described the CANGEN algorithm claimed to generate unique SMILES strings for graphs representing molecules, but the algorithm fails for a number of simple cases and cannot be considered a correct method for representing a graph canonically. There is no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, double bond geometry; these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES.
A notable feature of these rules is. The term isomeric SMILES is applied to SMILES in which isotopes are specified. In terms of a graph-based computational procedure, SMILES is a string obtained by printing the symbol nodes encountered in a depth-first tree traversal of a chemical graph; the chemical graph is first trimmed to remove hydrogen atoms and cycles are broken to turn it into a spanning tree. Where cycles have been broken, numeric suffix labels are included to indicate the connected nodes. Parentheses are used to indicate points of branching on the tree; the resultant SMILES form depends on the choices: of the bonds chosen to break cycles, of the starting atom used for the depth-first traversal, of the order in which branches are listed when encountered. Atoms are represented by the standard abbreviation of the chemical elements, in square brackets, such as for gold. Brackets may be omitted in the common case of atoms which: are in the "organic subset" of B, C, N, O, P, S, F, Cl, Br, or I, have no formal charge, have the number of hydrogens attached implied by the SMILES valence model, are the normal isotopes, are not chiral centers.
All other elements must be enclosed in brackets, have charges and hydrogens shown explicitly. For instance, the SMILES for water may be written as either O or. Hydrogen may be written as a separate atom; when brackets are used, the symbol H is added if the atom in brackets is bonded to one or more hydrogen, followed by the number of hydrogen atoms if greater than 1 by the sign + for a positive charge or by - for a negative charge. For example, for ammonium. If there is more than one charge, it is written as digit.
Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In the context of food production, it may more broadly refer to any process in which the activity of microorganisms brings about a desirable change to a foodstuff or beverage; the science of fermentation is known as zymology. In microorganisms, fermentation is the primary means of producing ATP by the degradation of organic nutrients anaerobically. Humans have used fermentation to produce beverages since the Neolithic age. For example, fermentation is used for preservation in a process that produces lactic acid found in such sour foods as pickled cucumbers and yogurt, as well as for producing alcoholic beverages such as wine and beer. Fermentation occurs within the gastrointestinal tracts including humans. Below are some definitions of fermentation, they range from general usages to more scientific definitions.
Preservation methods for food via microorganisms. Any process that produces alcoholic beverages or acidic dairy products. Any large-scale microbial process occurring with or without air. Any energy-releasing metabolic process that takes place only under anaerobic conditions. Any metabolic process that releases energy from a sugar or other organic molecule, does not require oxygen or an electron transport system, uses an organic molecule as the final electron acceptor. Along with photosynthesis and aerobic respiration, fermentation is a way of extracting energy from molecules, but it is the only one common to all bacteria and eukaryotes, it is therefore considered the oldest metabolic pathway, suitable for an environment that does not yet have oxygen. Yeast, a form of fungus, occurs in any environment capable of supporting microbes, from the skins of fruits to the guts of insects and mammals and the deep ocean, they harvest sugar-rich materials to produce ethanol and carbon dioxide; the basic mechanism for fermentation remains present in all cells of higher organisms.
Mammalian muscle carries out the fermentation that occurs during periods of intense exercise where oxygen supply becomes limited, resulting in the creation of lactic acid. In invertebrates, fermentation produces succinate and alanine. Fermentative bacteria play an essential role in the production of methane in habitats ranging from the rumens of cattle to sewage digesters and freshwater sediments, they produce hydrogen, carbon dioxide and acetate and carboxylic acids. Acetogenic bacteria oxidize the acids, obtaining more acetate and either formate. Methanogens convert acetate to methane. Fermentation reacts NADH with an organic electron acceptor; this is pyruvate formed from sugar through glycolysis. The reaction produces NAD+ and an organic product, typical examples being ethanol, lactic acid, carbon dioxide, hydrogen gas. However, more exotic compounds can be produced by fermentation, such as butyric acetone. Fermentation products contain chemical energy, but are considered waste products, since they cannot be metabolized further without the use of oxygen.
Fermentation occurs in an anaerobic environment. In the presence of O2, NADH, pyruvate are used to generate ATP in respiration; this is called oxidative phosphorylation, it generates much more ATP than glycolysis alone. For that reason, fermentation is utilized when oxygen is available; however in the presence of abundant oxygen, some strains of yeast such as Saccharomyces cerevisiae prefer fermentation to aerobic respiration as long as there is an adequate supply of sugars. Some fermentation processes involve obligate anaerobes. Although yeast carries out the fermentation in the production of ethanol in beers and other alcoholic drinks, this is not the only possible agent: bacteria carry out the fermentation in the production of xanthan gum. In ethanol fermentation, one glucose molecule is converted into two ethanol molecules and two carbon dioxide molecules, it is used to make bread dough rise: the carbon dioxide forms bubbles, expanding the dough into a foam. The ethanol is the intoxicating agent in alcoholic beverages such as wine and liquor.
Fermentation of feedstocks, including sugarcane and sugar beets, produces ethanol, added to gasoline. In some species of fish, including goldfish and carp, it provides energy; the figure illustrates the process. Before fermentation, a glucose molecule breaks down into two pyruvate molecules; the energy from this exothermic reaction is used to bind inorganic phosphates to ATP and convert NAD+ to NADH. The pyruvates break down into two acetaldehyde molecules and give off two carbon dioxide molecules as a waste product; the acetaldehyde is reduced into ethanol using the energy and hydrogen from NADH, the NADH is oxidized into NAD+ so that the cycle may repeat. The reaction is catalysed by the enzymes pyruvate alcohol dehydrogenase. Homolactic fermentation is the simplest type of fermentation; the pyruvate from glycolysis undergoes a simple redox reaction. It is unique because it is one of the only respiration processes to not produce a gas as a byproduct. Overall, one molecule of glucose is converted to two molecules of lactic ac
A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed by the reception of a proton by a base—in other words, it is a base with a hydrogen ion added to it. On the other hand, a conjugate base is what is left over after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a species formed by the removal of a proton from an acid; because some acids are capable of releasing multiple protons, the conjugate base of an acid may itself be acidic. In summary, this can be represented as the following chemical reaction: Acid + Base ⇌ Conjugate Base + Conjugate Acid Johannes Nicolaus Brønsted and Martin Lowry introduced the Brønsted–Lowry theory, which proposed that any compound that can transfer a proton to any other compound is an acid, the compound that accepts the proton is a base. A proton is a nuclear particle with a unit positive electrical charge. A cation can be a conjugate acid, an anion can be a conjugate base, depending on which substance is involved and which acid–base theory is the viewpoint.
The simplest anion which can be a conjugate base is the solvated electron whose conjugate acid is the atomic hydrogen. In an acid-base reaction, an acid plus a base reacts to form a conjugate base plus a conjugate acid: Conjugates are formed when an acid loses a hydrogen proton or a base gains a hydrogen proton. Refer to the following figure: We say that the water molecule is the conjugate acid of the hydroxide ion after the latter received the hydrogen proton donated by ammonium. On the other hand, ammonia is the conjugate base for the acid ammonium after ammonium has donated a hydrogen ion towards the production of the water molecule. We can refer to OH- as a conjugate base of H2O, since the water molecule donates a proton towards the production of NH+4 in the reverse reaction, the predominating process in nature due to the strength of the base NH3 over the hydroxide ion. Based on this information, it is clear that the terms "Acid", "Base", "conjugate acid", "conjugate base" are not fixed for a certain chemical species.
The strength of a conjugate acid is directly proportional to its dissociation constant. If a conjugate acid is strong, its dissociation will have a higher equilibrium constant and the products of the reaction will be favored; the strength of a conjugate base can be seen as the tendency of the species to "pull" hydrogen protons towards itself. If a conjugate base is classified as strong, it will "hold on" to the hydrogen proton when in solution and its acid will not dissociate. On the other hand, if a species is classified as a strong acid, its conjugate base will be weak in nature. An example of this case would be the dissociation of Hydrochloric acid HCl in water. Since HCl is a strong acid, its conjugate base will be a weak conjugate base. Therefore, in this system, most H+ will be in the form of a Hydronium ion H3O+ instead of attached to a Cl anion and the conjugate base will be weaker than a water molecule. If an acid is weak, its conjugate base will be strong; when considering the fact that the Kw is equal to the product of the concentrations of H+ and OH.
A weak acid will have a low concentration of H+. The Kw divided by a low H+ concentration will result in a low OH- concentration as well. Therefore, weak acids will have weak conjugate bases, unlike the misconception that they have strong conjugate bases; the acid and conjugate base as well as the base and conjugate acid are known as conjugate pairs. When finding a conjugate acid or base, it is important to look at the reactants of the chemical equation. In this case, the reactants are the acids and bases, the acid corresponds to the conjugate base on the product side of the chemical equation. To identify the conjugate acid, look for the pair of compounds that are related; the acid–base reaction can be viewed in a before and after sense. The before is the reactant side of the after is the product side of the equation; the conjugate acid in the after side of an equation gains a hydrogen ion, so in the before side of the equation the compound that has one less hydrogen ion of the conjugate acid is the base.
The conjugate base in the after side of the equation lost a hydrogen ion, so in the before side of the equation, the compound that has one more hydrogen ion of the conjugate base is the acid. Consider the following acid–base reaction: HNO3 + H2O → H3O+ + NO−3Nitric acid is an acid because it donates a proton to the water molecule and its conjugate base is nitrate; the water molecule acts as a base because it receives the Hydrogen Proton and its conjugate acid is the hydronium ion. One use of conjugate acids and bases lies in buffering systems. In a buffer, a weak acid and its conjugate base, or a weak base and its conjugate acid, are used in order to limit the pH change during a titration process. Buffers have both non-organic chemical applications. For example, besides buffers being used in lab processes, our blood acts as a buffer to maintain pH; the most important buffer in our bloodstream is the carbonic acid-bicarbonate buffer, which prevents drastic pH changes when CO2 is introduced. This functions as such: CO 2 + H 2 O ↽ − − ⇀ H 2 CO 3 ↽
E numbers are codes for substances that are permitted to be used as food additives for use within the European Union and EFTA. The "E" stands for "Europe". Found on food labels, their safety assessment and approval are the responsibility of the European Food Safety Authority. Having a single unified list for food additives was first agreed upon in 1962 with food colouring. In 1964, the directives for preservatives were added, 1970 for antioxidants and 1974 for the emulsifiers, stabilisers and gelling agents; the numbering scheme follows that of the International Numbering System as determined by the Codex Alimentarius committee, though only a subset of the INS additives are approved for use in the European Union as food additives. Outside the European continent plus Russia, E numbers are encountered on food labelling in other jurisdictions, including the Cooperation Council for the Arab States of the Gulf, South Africa, New Zealand and Israel, they are though still found on North American packaging on imported European products.
In some European countries, "E number" is sometimes used informally as a pejorative term for artificial food additives, products may promote themselves as "free of E numbers". This is incorrect, because many components of natural foods have assigned E numbers, e.g. vitamin C and lycopene, found in carrots. NB: Not all examples of a class fall into the given numeric range. Moreover, many chemicals in the E400–499 range, have a variety of purposes; the list shows all components that had an E-number assigned. Not all additives listed are still allowed in the EU, but are listed as they used to have an E-number. For an overview of allowed additives see information provided by the Food Standards Agency of the UK. Food Chemicals Codex List of food additives List of food additives, Codex Alimentarius Codex Alimentarius, the international foods standards, established by the Food and Agriculture Organization and the World Health Organization in 1963 See their document "Class Names and the International Numbering System for Food Additives" Joint FAO/WHO Expert Committee on Food Additives publications at the World Health Organization Food Additive Index, JECFA, Food and Agriculture Organization E-codes and ingredients search engine with details/suggestions for Muslims Current EU approved additives and their E Numbers Food Additives in the European Union Food Additives, Food Safety, website of the European Union.
Includes Lists of authorised food additives Food additives database The Food Additives and Ingredients Association, FAIA website, UK
Sodium tartrate is used as an emulsifier and a binding agent in food products such as jellies and sausage casings. As a food additive, it is known by the E number E335; because its crystal structure captures a precise amount of water, it is a common primary standard for Karl Fischer titration, a common technique to assay water content. Monosodium tartrate Properties of Sodium Tartrate at linanwindow Properties of Sodium Tartrate at JTBaker