Food additives are non-nutritive substances that are intentionally added to food in small amounts to improve its appearance, flavor, and texture or storage properties.
II. Types of food additives:
1. Action mechanism of antioxidants
The mechanism of antioxidant action is complex and there are many possibilities. For example, some antioxidants are easy to be oxidized and react with oxygen to protect food. Such as VE. Some antioxidants can release hydrogen ions in the oil in the automatic oxidation process produced by the peroxide decomposition damage, so that it can not form aldehydes or ketone products such as dilauryl thiodipropionate. Some antioxidants may combine with the peroxides produced by them to form hydroperoxides, which interrupt the oxidation process of oil and thus prevent the oxidation process from proceeding, while the antioxidant radicals themselves form antioxidant radicals, which can form stable dimers, or with the peroxide radical ROO-. Combine to form a stable compound.
2. Several commonly used fat-soluble antioxidants
(1) BHA: It is one of the most widely used antioxidants in the world and also one of the most commonly used antioxidants in China. Synergistic effects with other antioxidants, and the use of synergistic agents such as citric acid, its antioxidant effect is more significant. BHA is generally considered to be less toxic and safer.
(2) BHT: dibutyl hydroxytoluene. Compared with other antioxidants, the stability is higher, the heat resistance is good, in the ordinary cooking temperature it does not affect,; the antioxidant effect is good, for the long-term preservation of food and baked food very effective. It is a cheap antioxidant widely used in the world especially in aquatic products processing. Commonly used with BHA and with citric acid or other organic acids as synergist. It's slightly more toxic than BHA.
(3) PG: propyl gallate. It's stable for heat. The antioxidant effect of PG on lard was stronger than that of BHA and BHT, and the toxicity was lower.
(4) TBHQ: terbutylhydroquinone. Is a relatively new class of phenolic antioxidants, its antioxidant effect is better.
These substances all produce sulfur dioxide (SO2), which meets water and forms sulfurous acid (H2SO3). Besides bleaching, it also has antiseptic effect. In addition, because of the strong reducibility of sulfurous acid, can consume the oxygen in the tissue of fruits and vegetables, inhibit the activity of oxidase, can prevent the oxidation of vitamin C in fruits and vegetables.
Sulfites are metabolized into sulfates in the body and are excreted from the urine by a detoxification process. Sulfites are not suitable for animal foods to avoid unpleasant odors. Sulfites have destructive effects on vitamin B1, so B1 content of foods such as meat, grains, dairy products and nuts are not suitable. Its use in countries such as the United States is severely restricted because of its ability to cause allergic reactions.
Also known as pigment, food coloring is to improve the sensory properties of a class of substances. According to their properties and sources, edible pigments can be divided into natural edible pigments and synthetic edible pigments.
1. Edible synthetic pigment belongs to synthetic pigment. Characteristics of food synthetic pigment: bright colors, stable properties, strong coloring power, strong fastness, can obtain any color, plus low cost, easy to use. But synthetic pigments are mostly harmful to humans. Some of the toxicity of synthetic pigments are directly toxic to human body due to their chemical properties. Some or produce harmful substances in the process of metabolism; Arsenic, lead or other harmful compounds may also contaminate the production process.
2. Edible natural pigment, edible natural pigment is mainly extracted from animal and plant tissues, but the composition of natural pigment is more complex, after the purification of natural pigment, its role may be different from the original. In addition, the chemical structure may change during the refining process. In addition, in the process of processing, there is the possibility of pollution, so we can not think of natural pigment is pure and harmless.
Synthetic food coloring, like other food additives, requires rigorous toxicological evaluation for safe use. Including chemical structure, physical and chemical properties, purity, existing forms in food and degradation process and degradation products; (2) with the food is absorbed by the body, in the tissues and organs of the retention distribution, metabolic transformation and excretion status; (3) biological changes caused by itself and its metabolites in the body, as well as possible toxicity to the body and its mechanism. Including acute toxicity, chronic toxicity, effects on reproduction, embryo toxicity, teratogenicity, mutagenicity, carcinogenicity, sensitization, etc.
Protective agent 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 pigment directly to food coloring, sometimes also need to add an appropriate amount of color protection agent, so that the product presents a good color.
1. Hair color principle and other functions of color protectants:
Color protection, in order to make meat products to show a bright red, in the processing process to add more nitrate (sodium or potassium) or nitrite. Nitrate is reduced to nitrite under the action of bacterial nitrate reductase. Nitrite forms nitrite under acidic conditions. Nitrite (NO) can also be decomposed at room temperature, where the nitrite generated will quickly react with myoglobin to produce stable, bright, bright red nitrite myoglobin. So that the meat can maintain a stable color. Bacteriostatic effect: nitrite in meat products, on the inhibition of microbial proliferation has a certain role.
2. The application of color protection agent
Nitrite is one of the acute toxic substances in the additive, is a highly toxic drug, can make normal hemoglobin into methemoglobin, lose the ability to carry oxygen, resulting in hypoxia. Secondly, nitrite is the precursor of nitrite compounds, and its carcinogenicity has attracted international attention. Therefore, all aspects require the addition of nitrate and nitrite to ensure the color of food additives in beverages
Limit the case at the minimum level.
Ascorbic acid has a high affinity with nitrite and can prevent nitrosation in vivo, thus almost completely inhibiting the production of nitrosocompounds. So adding the right amount of ascorbic acid to meat marinades may prevent the formation of carcinogens.
Although the use of nitrate and nitrite has been greatly restricted, but still continue to be used at home and abroad. The reason is that nitrite has a special effect on preserving the color, aroma and taste of preserved meat products. The more important reason is the inhibitory effect of nitrite on clostridium botulinum. However, there are strict requirements on the food used and the amount of use and residue.
Enzyme preparation refers to the extraction from living organisms (including animals, plants and microorganisms) of substances with the enzymatic properties of biocatalytic ability. Mainly used to speed up the food processing process and improve the quality of food products.
Among the enzymes allowed in China are papain, derived from the latex of unripe papaya; And proteases made by aspergillus oryzae, bacillus subtilis, etc. N-amylase - mostly from bacillus subtilis; Glycosylated amylase -- the strains used in the production of this enzyme preparation in China include aspergillus Niger, root-enzyme, monascus, and endosporin; Pectinase produced by aspergillus Niger, aspergillus oryzae and aspergillus flavus.
A substance used to supplement, enhance, or improve the original taste or taste of food. Some are called umami or taste agents.
China allows the use of sodium glutamate, disodium -guanylate and disodium 5 '-inosine 5' -disodium -present taste nucleotide, disodium succinate and l-alanine flavor enhancers.
Sodium glutamate is monosodium l-glutamate containing one molecule of crystalline water. It dissolves easily in water and loses crystal water at 150℃, pyrrolidone occurs at 210℃, pyroglutamic acid is generated, and decomposes at 270℃ or so. It is stable to light, and has the effect of desorption when heated under alkaline conditions, and the flavor force is decreased. Pyrrolidone may easily occur when heated under acidic conditions with a PH below 5, turning it into pyroglutamic acid with reduced flavor strength. Heating is rarely changed when it is neutral.
Glutamic acid is a low toxic substance. There is no toxicity problem in the general dosage, and the nucleotide series of flavor enhancers are widely found in a variety of food. No special rules are required.
Over the years, many meat extracts, yeast extracts, hydrolyzed animal proteins and hydrolyzed plant proteins have been developed.
It refers to the substances that can inhibit the reproduction of microorganisms in food, prevent food from spoiling and prolonging the shelf life of food. Preservatives are generally divided into acid preservatives, ester preservatives and biological preservatives.
First, acid preservative
Commonly used are benzoic acid, sorbic acid and propionic acid (and its salts). The bacteriostatic effect of these preservatives depends largely on their undissociated acid molecules, and their effectiveness varies with PH. The more acidic the preservatives, the better the effect, and the less effective they are in alkaline environments.
1. Benzoic acid and its sodium salts: benzoic acid is also known as benzoic acid. Because of its low solubility in water, it is used more sodium salt. Low cost.
After entering the body, most of the benzoic acid was combined with glycine to form hippuric acid and was discharged from the urine within 9~15 hours, and the rest was combined with glucuronic acid to detoxify. But because sodium benzoate has certain toxicity, it has been gradually replaced by sodium sorbate.
2. Sorbic acid and its salts: also known as sorbus acid. Because of the limited solubility in water, potassium salt is often used. Sorbic acid is a kind of 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 food component, which can be considered harmless to human body according to the data.
3. Propionic acid and its salts: the bacteriostatic effect is weak, the usage is high. Often used in bread and pastry, the price is lower.
Propionic acid and its salt, its toxicity is low, can be considered as a normal component of food, but also a normal intermediate product of human metabolism.
4. Dehydroacetic acid and its sodium salt: it is a broad-spectrum preservative, especially for mold and yeast, which is 2~10 times stronger than sodium benzoate. It is quickly absorbed by the body and distributed in the blood and many tissues. However, it has the function of inhibiting a variety of oxidase in vivo, and its safety is doubted, so it has been gradually replaced by sorbic acid, and its ADI value has not been specified.
Second, ester type preservative
Including hydroxybenzoate esters (there are a, b, c, isopropyl, d, isoding, heptyl, etc.). Higher costs. It has extensive antibacterial effect 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 lactobacillus. The mechanism of action is to inhibit the activity of respiration enzyme and electron transfer enzyme system in microbial cells, and destroy the structure of microbial cell membrane. Its bacteriostatic ability increased with the increase of alkyl chain. Solubility decreases with the increase of ester chain length, but toxicity decreases. However, the combination of p-hydroxybenzoate and propyl ester can increase its solubility and has synergistic effect. It is rapidly and completely absorbed in the gastrointestinal tract, hydrolyzed into hydroxybenzoic acid and discharged from the urine without accumulation in the body. Only propyl and ethyl esters are used in China.
Mainly lactococcin. Streptococcus lactis is the metabolite of streptococcus lactis, which can be extracted by fermentation of streptococcus lactis. The advantage of lactococcin is that it can be degraded by proteolytic enzymes in the human digestive tract. Candy containing food additives is not absorbed into the body in its original form, so it is a relatively safe preservative. , does not alter the normal gut flora as antibiotics do, and causes resistance to other commonly used antibiotics, much less cross-resistance to other antibiotics.
Other preservatives include sodium diacetate, which is both a preservative and a chelating agent. For grain and soybean products to prevent the growth of mold. Sec-butylamine, which should not be added to processed foods, should only be used in fruits and vegetables stored in antiseptic. The fresh-keeping agents such as kemuiling and baoguiling are all the preparations with zhongbutylamine as the effective ingredient. The increase of carbon dioxide and the partial pressure of carbon dioxide affects the use of oxygen by aerobic microorganisms and can stop the respiration and metabolism of various microorganisms. For example, the presence of a large amount of carbon dioxide in high food can change the PH of food surface and make microorganisms lose the necessary conditions for survival. But carbon dioxide can only inhibit microbial growth, not kill it.
It refers to food additives that sweeten food. It can be divided into :(1) natural sweeteners, sugar alcohols and non-sugar. The sugar alcohols are: xylitol, sorbitol, mannitol, lacttol, maltitol, isomaltitol, red sugar alcohol; Non-carbohydrates include: stevia glucosinolates, licorice, kiwi, nordhanin, somasweet. (2) artificial artificial sweetener sulfanilamide class: saccharin, cyclohexyl sulfanilate sodium, potassium sulfanilate acetyl. The dipeptides are: aspartame (aspartame), 1-a-aspartame -N- (2, 2, 4, 4-tetramethyl - 3-sulfide methyl) - d-alanine (also known as alizarin). Sucrose derivatives are: sucralose, isomalt ketositol (also known as palagin sugar), new sugar (fructose oligosaccharide).
In addition, according to the nutritional value can be divided into nutritive and non-nutritive sweeteners, such as sucrose, glucose, fructose and other natural sweeteners. As these sugars not only give food to sweet taste, or an important nutrient, to provide the body with heat, is usually regarded as food raw materials, generally not as food additives to control.
The scientific name is o-sulfonyl benzoyl, is a kind of artificial sweetener widely used in the world, the price is low, the sweetness is big, its sweetness is equivalent to sucrose 300~500 times, because saccharin in the water solubility is low, so the Chinese additive standards for the use of sodium salt (saccharin sodium), when the amount of bitter. Saccharin sodium is thought to be insoluble in the body, unused, and largely excreted from urine without damaging kidney function. Does not change the activity of the enzyme system in vivo. Saccharin has been widely used around the world for decades, but its toxic effects on humans have yet to be discovered.
2. Cyclohexylamine sulfonate (cylamine) was listed as a "generally considered safe substance" and widely used in the United States in 1958, but it was reported to have carcinogenic effects on animals in the 1970s, and the 1982 FAO/WHO report proved to be non-carcinogenic. Long-term trials by the FDA were declared noncarcinogenic in 1984. But the national scientific research council and the national academy of sciences still consider them carcinogenic and possibly carcinogenic. Therefore, it is still prohibited to be used in food in the United States.
Aspartame methyl aspartate (aspartame) is 100 to 200 times sweeter than sucrose and tastes close to sucrose. Is a dipeptide derivative, after eating in the body decomposition into the corresponding amino acids. China stipulates that food other than canned food can be used in appropriate quantities as required for production.
In addition, many dipeptide derivatives containing aspartic acid, such as alicin, also belong to amino acid sweetener, natural raw material synthesis, high sweetness. Candy containing food additives
4. Potassium acetylsulfanilate
This product is stable to light and heat (225℃), has a long sweet sensation, and tastes better than saccharin sodium. After absorption, it is quickly removed from the urine and not stored in the body. When used in combination with aspartame 1:1, it has obvious synergistic effect.
5. Sugar alcohol sweeteners
Sugar alcohol sweeteners belong to a class of natural sweeteners. Their sweetness is similar to that of sucrose. Many varieties, such as sorbitol, xylitol, mannitol and maltitol, are found in natural foods, most of which are obtained by hydrogenating the corresponding sugars. The precursors come from natural foods. Because sugar alcohol sweetener raises glycaemic index low, also do not produce acid, it is used as sweetener of diabetic, fat patient and have the effect that prevents tooth decay more. Most of these substances have a certain degree of water absorption, which can improve the rehydration of dehydrated food, control crystallization and reduce water activity. However, because of the low absorption rate of sugar alcohol, especially xylitol, it has a certain ability to cause diarrhea when consumed in large quantities.
Is a strong sweet component of stevia, a diterpene-containing glycoside. About 300 times sweeter than table sugar. However, stevioside has a poor taste, licorice taste, and a high concentration of bitter taste, so it is often mixed with sucrose, fructose, glucose, and citric acid, malic acid, etc. to reduce the bitter taste or through fructosyltransferase or glucosyltransferase to change the structure and correct its shortcomings. A large number of toxicity experiments have been done on it in foreign countries, but the toxicity effect has not been shown. However, in the countries with a longer consumption time, such as Paraguay, the product has been used for 100 years, and Japan has also been used for more than 15 years. No adverse side effects have been reported.