Antioxidants

作者：admin  点击次数：140  发布时间：2025-05-22

Antioxidants are substances that can prevent or delay the oxidation, decomposition and deterioration of fats or food ingredients and improve the stability of food. They can be divided into two categories: water-soluble and fat-soluble. Some other substances do not have antioxidant effects themselves, but can synergize antioxidant effects and significantly improve the antioxidant effect. These substances are called antioxidant promoters. The most common ones are citric acid, tartaric acid ascorbic acid (vitamin C), etc.
Antioxidants are a class of substances that can react with free radicals to terminate the auto-oxidation process. They are mainly used to prevent the oxidation and rancidity of fats and fat-rich foods, as well as fading, browning, and vitamin destruction caused by oxidation. The auto-oxidation of fats has a fairly long induction period, which depends on many factors, mainly the activation degree, and antioxidants can reduce the oxygen content in the medium. Antioxidants can only hinder the process of oxidation to delay the time when the fats begin to oxidize and deteriorate, and it is impossible to restore the oxidized products.
(I) Butylated hydroxyanisole
1. Antioxidant effect
Butylated hydroxyanisole (BHA) is relatively stable to heat and is easily destroyed under alkaline conditions, so it is a good antioxidant. The antioxidant effect of 0.02% is about 10% higher than that of 0.01%, but when it is increased to more than 0.02%, its antioxidant effect is reduced. It is especially suitable for baked products made of animal fat. This product has the characteristic of changing color when it reacts with transition metal ions, so iron and copper containers should be avoided when using it. Mixing citric acid or tartaric acid with this product not only has a synergistic effect, but also can prevent the coloring effect caused by metal ions. BHA has a certain volatility and can be distilled by steam, so it is easy to lose in high-temperature products, especially in boiled and fried products. BHA can also be used as food packaging materials.
2. Impact on food safety It is generally believed that BHA has low toxicity and is relatively safe. The main concerns about BHA's physiology are its effects on the forestomach of rodents and possible damage to related tissues of other animals. Experiments with other similar compounds have shown that compounds with similar structures can also cause proliferation of the forestomach, but BHA seems to be the most active of this class of compounds. Experiments with other animals that do not have forestomach, such as guinea pigs, dogs and monkeys, have shown that no proliferative changes in the stomach will occur at the maximum tolerated dose of these animals. However, these experiments cannot infer the possibility that BHA can cause relevant reactions in humans. So far, no reproductive toxicity has been found in BHA. The amount of BHA that humans may ingest every day is 2 to 3 times lower than the ineffective dose, so the use of BHA as a food antioxidant will not cause damage to human health.
3. Scope of use and dosage
The scope of use and dosage of butylated hydroxyanisole are shown in Table 4-6.
Table 4-6
Additive name
Butylated hydroxyanisole
Scope of use of butylated hydroxyanisole and its use
Scope of use
Fats, oils and emulsified sweetened fat products, canned nuts and seeds, ready-to-eat cereals, biscuits, cured meat products, etc.
Gum-based candies
Maximum usage/(y/kg)
0.2
0.4
(II) Butylated hydroxytoluene
1. Antioxidant effect Compared with other antioxidants, butylated hydroxytoluene (BHT) has higher stability and better heat resistance. It will not color when reacting with metal ions. It has little effect at ordinary cooking temperatures and has good antioxidant effect. It is very effective for long-term storage of food and baked food. It is currently a cheap antioxidant widely used internationally, especially in aquatic product processing. It is generally used in combination with BHA, and citric acid or other organic acids are used as synergists.
2. Impact on food safety
The United States has reported that BHT has a carcinogenic effect and may inhibit the activity of human respiratory enzymes, so Greece, Turkey, Indonesia and other countries have banned it. However, after the US FDA banned it for a while, it was allowed to be used again because it was proven that safety can still be guaranteed. The no-effect dose observed in rats is 7.5 mg/(kg body weight.d), which is the main basis for the Scientific Committee on Food (SCF) to formulate the ADI value (0~0.05 mg/kg). The minimum intake of BHT that causes liver hyperplasia in rats is about 50 mg/kg body weight, which exceeds the minimum dose that causes blood coagulation changes and is about 1/1000 of the ADI value currently specified by the Scientific Committee on Food (SCF). Therefore, it can be seen that the current intake of BHT from food will not produce adverse effects.
3. Scope of use and dosage
The scope of use and dosage of butylated hydroxytoluene are shown in Table 4-7.
Table 4-7
Additive name
Butylated hydroxytoluene
Scope of use and dosage of butylated hydroxytoluene
Usage diagram
Fats, oils and emulsified fat products, canned nuts and seeds, ready-to-eat cereals, instant rice and flour products, biscuits, cured meat products, air-dried, oven-dried, pressed and other aquatic products
Maximum dosage/(g/kg)
0.2
(III) Propyl gallate
1. Antioxidant effect
Propyl gallate (PG) has a good antioxidant effect on vegetable oils and a better antioxidant effect on lard than BHA and BHT. PG has a good synergistic effect when used in combination with BHA and BHT. When mixed, adding the synergist citric acid has the best antioxidant effect. When this concentration is exceeded, PG can be called an oxidation enhancer and promotes oxidation.
Studies on reproductive toxicity of esters (the most sensitive toxicological indicator) have determined that the no-effect dose in food is 1000 mg/kg, which is equivalent to 500 mg/kg body weight, which can cause kidney damage. Long-term studies have shown that they are not carcinogens and cannot cause forestomach tumors. Based on the above toxicological data, the current use of propyl gallate as an antioxidant will not cause damage to human health. It is worth noting that propyl gallate can cause contact dermatitis in bakers and other people who come into contact with the substance.
3. Scope of use and dosage
The scope of use and dosage of propyl gallate are shown in Table 4-8.
Table 4-8
Additive name
Propyl gallate
Scope and dosage of propyl gallate
Scope of use
Fats, oils and emulsified fat products, canned nuts and seeds, ready-to-eat cereals, instant rice and flour products, biscuits, cured meat products, air-dried, dried, pressed and other aquatic products
Maximum dosage/(g/kg)
0.1
(IV) Tert-butylhydroquinone
1. Antioxidant effect
Tert-butylhydroquinone (TBHQ