Dec 30, 2021
What are the common food additives?
First, antioxidants
1. Mechanism of action of antioxidants
The mechanism of action of antioxidants is complex and there are many possibilities. For example, some antioxidants are easily oxidized by themselves, first reacting with oxygen, thus protecting the food. Such as VE. Some antioxidants can release hydrogen ions to decompose and destroy the peroxide produced in the automatic oxidation process of oil, so that it can not form aldehydes or ketones such as dipropionate dilauryl thiolate. Some antioxidants may combine with peroxides produced by them to form hydroperoxides, so as to interrupt the process of oil oxidation and thus organize the process of oxidation, and themselves form antioxidant free radicals, but the antioxidant free radicals can form stable dimers, or with the peroxide free radicals ROO. Combine to form stable compounds. Such as BHA, BHT, TBHQ, PG, tea polyphenols, etc.
2. Several commonly used lipid-soluble antioxidants
(1) BHA: butylated hydroxyanisole. Because the effect of heating preservation is good, effective in the preservation of food, it is one of the antioxidants widely used in the world at present, and one of the commonly used antioxidants in our country. It has synergistic effect with other antioxidants, and when used with synergistic agents such as citric acid, its antioxidant effect is more significant. It is generally considered that BHA has little toxicity and is relatively safe.
(2) BHT: dibutyl-hydroxytoluene. Compared with OTHER antioxidants, high stability, good heat resistance, at ordinary cooking temperature is not affected, antioxidant effect is also good, used for long-term preservation of food and baked food is very effective. It is a cheap antioxidant widely used in the world, especially in aquatic processing. Generally used with BHA, and citric acid or other organic acids as synergists. Compared with BHA, the toxicity is slightly higher.
(3) PG: propyl gallate. It's stable to heat. The antioxidant effect of PG on lard was stronger than that of BHA and BHT. Low toxicity.
(4) TBHQ: terbutylhydroquinone. It is a relatively new class of phenolic antioxidants, and its antioxidant effect is better.
Two, bleach
Such substances can produce sulfur dioxide, sulfur dioxide in water is formed sulfite. In addition to bleaching, it also has anti-corrosion effect. In addition, due to the strong reducibility of sulfite, it can consume oxygen in fruit and vegetable tissues, inhibit the activity of oxidase, and prevent the oxidative destruction of vitamin C in fruits and vegetables. Sulfites are metabolized in the body as sulfates, which are excreted from the urine through a detoxification process. Compounds such as sulfites are not intended for use in animal-based foods to avoid unpleasant odors. Sulfite has a destructive effect on vitamin B1, so foods with more B1 content such as meat, cereals, dairy products and nuts are not suitable. Its use in the United States and other countries is heavily restricted because of its ability to cause allergic reactions.
Three, colorant
Also known as pigment, it is a kind of material that improves the sensory character of food after coloring. According to their properties and sources, food pigments can be divided into two categories: natural food pigments and synthetic food pigments.
1. Edible synthetic pigment belongs to artificial synthetic pigment. The characteristics of edible synthetic pigment: bright color, stable properties, strong coloring power, firmness, arbitrary color, low cost, easy to use. But synthetic pigments are mostly harmful to humans. Some of the toxicity of synthetic pigments are direct toxicity to human body due to their chemical properties. Some or produce harmful substances in the metabolic process; It can also be contaminated with arsenic, lead or other harmful compounds during production.
The synthetic pigment allowed to be used in our country at present is amaranth, carmine, red bright red (cherry red), new red, temptation red, lemon yellow, sunset yellow, bright blue, indigo and their own Al lake. And synthetic β-carotene, sodium copper chlorophyll and titanium dioxide.
2. Edible natural pigments, the use of natural pigments are mainly extracted from animal and plant tissues, the composition of human natural pigments is more complex, after purification of natural pigments, its role may be different from the original. In the process of refining, its chemical structure may also change; In addition, in the process of processing, there is the possibility of contamination, so it can not be considered that natural pigment is pure and harmless. Like other food additives, synthetic food coloring needs strict toxicological evaluation in order to achieve the purpose of safe use. Including ① chemical structure, physical and chemical properties, purity, the form of presence in food and degradation process and degradation products; ② Retention distribution, metabolic transformation and excretion in tissues and organs after being absorbed by the body with food; ③ The biological changes caused by itself and its metabolites in the body, and the possible toxicity to the body and its mechanism. Including acute toxicity, chronic toxicity, reproductive effects, embryonic toxicity, teratogenicity, mutagenicity, carcinogenicity, sensitization and so on.
Four, color protection agent
Color protection agent is also known as hair color agent. In the process of food processing, in order to improve or protect the color of food, in addition to the use of pigments to directly color the food, sometimes also need to add the right amount of hair color agent, so that the product presents a good color
1. Hair color principle and other effects of hair color agent: (1) hair color effect, in order to make meat products bright red, in the processing process to add nitrate (sodium or potassium) or nitrite. Nitrate is reduced to nitrite under the action of bacterial nitrate reductase. Nitrite forms nitrite under acidic conditions. At room temperature, nitroso (NO) can also be decomposed to produce nitroso (NO), which will quickly react with myoglobin to form stable, bright, bright red nitrosate myoglobin. So that the meat can keep stable bright. ② Antibacterial effect: Nitrite in meat products, to inhibit the proliferation of microorganisms have a certain effect.
2. The application of hair colouring agent
Nitrite is one of the substances with strong acute toxicity in additives. It is a highly toxic drug, which can make normal hemoglobin become methemoglobin and lose the ability to carry oxygen, leading to hypoxia in tissues. Second, nitrite is the precursor of nitroso compounds, and its carcinogenicity has attracted international attention. Therefore, all aspects require the addition of nitrate and nitrite to be limited to the lowest level under the condition of ensuring hair color. Ascorbate has a high affinity for nitrite and prevents nitrosation in vivo, thus almost completely blocking the formation of nitroso compounds. So when meat curing, add the right amount of ascorbic acid, may prevent the formation of carcinogens.
Although the use of nitrate and nitrite has been greatly restricted, they still continue to be used at home and abroad. The reason is that nitrite plays a special role in maintaining the color, aroma and taste of salted meat products, and no ideal substitute material has been found so far. The more important reason is the inhibitory effect of nitrite on Clostridium botulinum. But the use of food and its usage and residues have strict requirements.
Five, enzyme preparation
Enzyme preparation refers to substances extracted from living organisms (including animals, plants and microorganisms) with enzyme characteristics of biocatalytic ability. It is mainly used to accelerate food processing and improve the quality of food products. The enzyme preparations allowed in China are: papain, which is extracted from the latex of immature papaya; And the protease prepared by Aspergillus oryzae, Bacillus subtilis, etc.; α-amylase - mostly from Bacillus subtilis; Saccharified amylase -- the strains used in the production of this enzyme preparation in China include Aspergillus Niger, rhizase, monkozyme and endosporase; Pectinase produced by Aspergillus Niger, Aspergillus oryzae and Aspergillus flavus.
Six, flavor enhancer
A substance used to supplement, enhance, or improve the original taste or taste of food. Some are called umami or taste agents.
The currently permitted flavor enhancer in China are sodium glutamate, disodium guanylate, disodium 5 '-inosinolate disodium 5' -flavoring nucleoglycerate disodium, disodium succinate and L-alanine. Sodium glutamate is a monosodium L-glutamate containing one molecule of crystal water. It is easily soluble in water, and loses crystal water at 150℃. Pyrrolidonylation occurs at 210℃ to generate pyroglutamic acid, and decomposition occurs at about 270℃. It is stable to light and racemic when heated under alkaline conditions, showing a decrease in flavor power. Pyrrolidone can easily occur when heated under acidic conditions with PH below 5, and become pyroglutamic acid, showing a decrease in flavor. At neutral temperature the heating changes very little. Glutamate is a low toxic substance. There is no toxicity problem under general dosage conditions, and nucleotide series of flavor enhancers are widely present in a variety of food. No special rules are required. In recent years, many meat extracts, yeast extracts, hydrolyzed animal proteins and hydrolyzed plant proteins have been developed.
7. Preservatives
It refers to the substances that can inhibit the reproduction of microorganisms in food, prevent food spoilage and prolong the storage period of food. Preservatives are generally divided into acid preservatives, ester preservatives and biological preservatives.
Acid preservatives: commonly used are benzoic acid, sorbic acid and propionic acid (and its salts). The bacteriostatic effect of these preservatives depends mainly on their undissociated acid molecules, and their potency varies with PH. The more acidic, the better, and they are almost ineffective in alkaline environments.
1. Benzoic acid and its sodium salts: Benzoic acid also known as benzoic acid. Because of its low solubility in water, its sodium salt is often used. The cost is low.
After entering the body, most of the benzoic acid and glycine within 9~15 hours to form hippuric acid and excreted from the urine, the remainder of the combination with glucuronic acid and detoxification.
2. Sorbic acid and its salts: also known as sorbus acid. Because of its limited solubility in water, its potassium salt is often used. Sorbic acid is an unsaturated fatty acid, which can participate in the normal metabolic process of the body and be assimilated to produce carbon dioxide and water. Therefore, sorbic acid can be regarded as a component of food and can be considered harmless to human body according to the current data.
3. Propionic acid and its salts: the antibacterial effect is weak, the usage is high. Often used for bread and pastry, the price is also lower. Propionic acid and its salts, which have low toxicity, can be considered as normal components of food and normal intermediates of human metabolism.
4. dehydroacetic acid and sodium salts: are broad spectrum preservatives, especially for mold and yeast antibacterial ability is strong, 2~10 times of sodium benzoate. The product is rapidly absorbed by the body and is distributed in the blood and many tissues. However, it has the effect of inhibiting a variety of oxidases in vivo, and its safety is questionable, so it has been gradually replaced by sorbic acid, and its ADI value has not been specified yet.
Two, ester preservatives: including parabens (A, B, C, isopropyl, butyl, isobutyl, heptane, etc.). The cost is higher. It has a wide range of antibacterial effects on mold, yeast and bacteria. It has a strong effect on mold and yeast, but a poor effect on bacteria, especially Gram-negative bacilli and lactic acid bacteria. The mechanism of action is to inhibit the activities of microbial cell respiration enzymes and electron transport enzymes, and destroy the structure of microbial cell membrane. Its bacteriostatic ability was enhanced with the increase of alkyl chain. The solubility decreases with the increase of ester carbon chain length, but the toxicity is opposite. However, the combination of ethyl paraben and propyl ester can increase the solubility and have synergistic effect. It can be absorbed quickly and completely in the gastrointestinal tract, hydrolyzed into hydroxy benzoic acid and discharged from the urine, not accumulated in the body. Our country is limited to propyl ester and ethyl ester at present.
Three, biological preservatives
It's mainly lactostreptococcin. Lactostreptococcin is a metabolite of lactostreptococci, which can be extracted by lactostreptococci fermentation. The advantage of Lactin is that it can be degraded by proteolytic enzymes in the digestive tract of the human body, so it is not absorbed into the body in its original form. It is a relatively safe preservative. , will not change the normal intestinal flora as antibiotics, and cause resistance to other commonly used antibiotics, let alone cross resistance with other antibiotics.
Other preservatives include sodium diacetate, which is both a preservative and a chelating agent. It has the effect of preventing mold reproduction in cereal and bean products. Sec-butylamine, this product should not be added to processed foods, only in the storage period of fruits and vegetables for preservative use. Commercially available preservatives such as clomedrin, Baoguolin, etc., are based on sec-butylamine as the active ingredient of the preparation. Carbon dioxide, the increase of carbon dioxide partial pressure, affect the use of oxygen by aerobic microorganisms, can terminate the respiration and metabolism of various microorganisms, such as high food there is a large amount of carbon dioxide can change the PH of food surface, so that microorganisms lose the necessary conditions for survival. But carbon dioxide inhibits microbial growth, not kills it.
8. Sweeteners
A food additive that gives food a sweet taste. According to the source, it can be divided into: (1) natural sweeteners, which are also divided into sugar alcohols and non-sugars. Among them, the sugar alcohols are: xylitol, sorbitol, mannitol, lactol, maltitol, isomaltitol, red fresh sugar alcohol; ② Non-saccharides include: stevia, licorice, kiritin, rohanin, somasame. (2) synthetic sweeteners including sulfonamides: saccharin, sodium cyclohexyl sulfamate, potassium acetosulfonate. Dipeptides include: methyl aspartate phenylpropionate (also aspartame), 1-A-aspartyl-N - (2, 2, 4, 4-tetramethyl-3-sulfide Sanymethyl) -D-alanine (also known as alitame). Derivatives of sucrose are: sucralose, isomaltolitol (also known as palaginose), new sugars (fructose oligosaccharides).
In addition, according to the nutritional value can be divided into nutritive and non-nutritive sweeteners, such as sucrose, glucose, fructose and so on are natural sweeteners. Because these sugars are not only endows food with sweet taste, but also important nutrients that supply heat to the human body, they are usually regarded as food raw materials and generally not controlled as food additives.
1. Saccharin: Its scientific name is o-sulfonyl benzoyl, which is a kind of artificial sweetener widely used in the world. It has low price and high sweetness, and its sweetness is 300~500 times that of sucrose. Because saccharin has low solubility in water, its sodium salt (sodium saccharin) is prescribed in China's additive standards, and it will taste bitter in large quantities. It is generally believed that saccharin is not broken down and used in the body, and most of it is excreted in the urine without damaging renal function. Does not change the activity of the enzyme system in the body. Saccharin has been widely used around the world for decades and has not been found to be toxic to humans.
2. Sodium cyclohexylamine sulfonate (cycetin) : In 1958 in the United States was listed as "generally considered to be safe substances" and widely used, but in the 1970s it was reported that this product has carcinogenic effect on animals, 1982 FAO/WHO report proved no carcinogenic. Long-term FDA trials were declared carcinogenic in 1984. But the National Science Research Council and the National Academy of Sciences still consider it pro-carcinogenic and possibly carcinogenic. So in the United States is still banned for food substances.
3. Methyl aspartate phenylalanine (aspartame). Its sweetness is 100~200 times that of sucrose, and its taste is close to that of sucrose. It is a dipeptide derivative that is broken down into corresponding amino acids in the body after consumption. Chinese regulations can be used for other foods outside canned food, its dosage needs to be used according to production. In addition, many dipeptide derivatives containing aspartate were also found, such as Alitame, which also belongs to amino acid sweetener and is synthesized from natural raw materials with high sweetness.
4. Potassium acetosulfonate: This product is stable to light and heat (225℃), sweet for a long time, taste because of sodium saccharin, quickly removed from urine after absorption, do not accumulate in the body, and aspartate methyl ester 1:1 combined, has obvious synergic effect.
5. Sugar alcohols sweeteners: sugar alcohols sweeteners belong to a class of natural sweeteners, whose sweetness is similar to sucrose, and are mostly low-heat energy sweeteners. There are many varieties, such as sorbitol, xylitol, mannitol and maltitol, etc. Some are found in natural foods, and most are obtained by hydrogenating the corresponding sugars. Its precursors come from natural foods. Because sugar alcohols sweeteners have low glycemic index and do not produce acid, they are often used as sweeteners for patients with diabetes and obesity and have the effect of preventing dental caries. the
