As a kind of additives, food preservatives are designed to maintain the integrity and beneficial ingredients of food. Up to now, my country has approved 32 kinds of food preservatives with low toxicity and high safety that can be used. In the classification of food preservatives, sorbic acid and benzoic acid are the most widely used, and they together account for nearly 70% of food preservative applications. Potassium sorbate and sodium benzoate are the typical representatives of the two categories. A comprehensive comparison of them can make food preservatives better used and provide a reference for the production and application of enterprises.
1 Comparison of antiseptic effects of potassium sorbate and sodium benzoate
1.1 The antiseptic effect of potassium sorbate
Among acids, sorbic acid has unsaturation and has a carboxyl group in its molecular structure. Free radicals are very convenient to combine with double bonds. The sulfhydryl groups of microbial enzymes contained in foods recombine with them to form covalent bonds. In this way, the purpose of destroying the enzyme system containing sulfhydryl groups and suppressing the growth of microorganisms can be achieved. Potassium sorbate is the potassium salt of sorbic acid. Its antiseptic mechanism is similar to that of sorbic acid. Both use to reduce the threat of dehydrogenase system and suppress the reproduction of harmful substances, thereby preserving. The preservatives on the market now mostly use potassium sorbate, which is mainly based on the water solubility and relative stability of potassium sorbate.
The 1% aqueous solution of potassium sorbate is neutral. This feature greatly facilitates the large-scale use of preservatives in actual production. The strength of its antiseptic effect is closely related to the change of PH value, and its antiseptic effect increases with the decrease of PH value. The optimal PH value of potassium sorbate is 3, but it still has a good antiseptic effect in foods with a pH value of 6.0-6.5.
In food production, potassium sorbate not only has a good effect on suppressing the survival rate of molds, yeasts and bacteria that are close to oxygen, but also prevents the growth of harmful microorganisms such as botulinum, staphylococcus, and salmonella. It is effective against anaerobic spores. Bacteria and beneficial microorganisms such as Lactobacillus acidophilus are almost ineffective. Generally, they can be compounded with beneficial microorganisms in the production of yogurt products.
1.2 The antiseptic effect of sodium benzoate
Benzoic acid has a good effect on fermenting mother fungus, Aspergillus and some bacteria. Under the condition of maximum use, if the PH value is less than 4.5 (the optimal pH value for anti-corrosion is 2.5～4.0), different fungi can be suppressed. Sodium benzoate is the sodium salt of benzoic acid. Sodium benzoate that has not been dissociated has a low HLB value and a high probability of passing through the cell membrane. After entering the cell, it will disturb the permeability of the cell membrane of bacterial microorganisms and hinder the absorption of amino acids. The benzoic acid molecule it carries makes the alkaline substance stored in the cell acidified, reduces the activity of the respiratory enzymes in the cell, prevents the contraction of acetyl-CoA, and prevents it from being preserved. It is similar to the use of potassium sorbate and sorbic acid. Sodium benzoate is more soluble in water than benzoic acid. In addition, it is not easy to decompose in the air. Under the same conditions, it has better performance in restraining brewing mother bacteria and bacteria. . The best antiseptic pH of sodium benzoate is 2.5-4.0. When the pH is greater than 4, the sterilization effect of its aqueous solution is not good. As a preservative in actual production, it is often used to store acidic foods such as high-acid fruits, jams, drinks, fruit syrups, etc.
2 Comparison of side effects of potassium sorbate and sodium benzoate
2.1 Toxic and side effects of potassium sorbate
Potassium sorbate has unsaturation, and the human metabolic system can receive and differentiate into water and carbon dioxide without residue. It is generally believed that it has less toxic and side effects. It is stable in the sealed state and is generally considered safe, but it may become toxic after being oxidized and discolored in contact with moist air. After being dissolved in water, it will easily cause the pH value to rise and produce weak alkalinity, which has a stimulating effect on human skin and internal gastrointestinal. Supposing that if the oral administration is too long, the bone growth rate will slow down, posing a threat to the kidney and liver.
2.2 Toxic and side effects of sodium benzoate
The ADI of sodium benzoate is 0-5 mg/kg -1 (the total amount of benzoic acid and its salts is calculated as benzoic acid) (based on the standards published by the Food and Agriculture Organization of the United Nations and the World Health Organization in 1994), and the LD50 is 4070 mg. kg -1. From the comparison of these two indicators, the toxicity of sodium benzoate is significantly higher than that of potassium sorbate.
2.2.1 Destruction of cell membrane structure
Sodium benzoate can destroy the order of the cell membrane structure and the functional disorder of the membrane, so that the number of broken cells increases and the cell balance system is crushed. It can also produce benzene with some freely active hydroxyl groups, leading to the proliferation of poisons. Benzene and benzene compounds are currently recognized as common chemical carcinogens. In the actual food production, when sodium benzoate is mixed with the food colorant lemon yellow or the food sweetener sodium saccharin, the toxicity has superimposed effects, which may cause secondary damage to the cell membrane.
2.2.2 Carcinogenicity
Using carbonated beverages added with sodium perbenzoate as a blueprint, we observed the activity of yeast cells and changes in related indicators, and found that sodium benzoate reacts with vitamin C to form a benzene ring, which can damage mitochondria and cause a decline in human immune function. There are also experiments that prove that drinking carbonated beverages containing sodium benzoate for too long can induce children to increase the frequency of inappropriate behaviors.
2.2.3 Damage to the nervous system
Benzoic acid is sometimes formed by collision and fusion of gastric juice with sodium benzoate. Benzoic acid is low-toxic, but frequent overdose exceeds the standard, and chronic benzene poisoning is close at hand. The specific manifestations are limp limbs, dizziness, sleepy dreams or tossing and turning at night, and other functional symptoms. The blood gradually changes, the white blood cells decrease, and then the blood deficiency syndrome occurs, the number of platelets decreases, and the human body is in danger of egg accumulation, leukemia or aplastic anemia May visit at any time. Sodium benzoate has a catnip-like “miraculous effect” on cats. Excessive consumption of foods containing sodium benzoate can lead to shrinkage of the brain, damage to the nervous system, and increased risk of cancer.
2.2.4 Other
In an acidic environment where the stirring is not evenly dispersed, sodium benzoate is difficult to dissolve in water, which may cause benzoic acid crystals in some substances to escape, resulting in excessive product additives and toxic side effects. Benzoic acid also has an antagonistic effect with calcium chloride. This antagonistic effect will cause the human body to reduce the absorption and utilization of essential elements, resulting in unfavorable physiological effects and biochemical reactions. Sodium benzoate can also cause damage to serum proteins, and its image twists and turns, which can induce recurrent acute urticaria and angioedema.
From the comparison of toxicological evaluation and toxic and side effects, the safety of potassium sorbate is higher than that of sodium benzoate, which is also an acidic preservative.
3. Conclusion
On the whole, the antiseptic effect and side effects of potassium sorbate are better than sodium benzoate. Compared with sodium benzoate, it has the characteristics of colorless, tasteless, odorless, high safety factor, and less harmful to the human body, which is very suitable for modern people. “Green” and “healthy” expectations. Internationally, in terms of food applications, potassium sorbate has the upper hand, with the advantages of being comfortable and unchanging. However, in terms of production and cost, potassium sorbate is complicated to prepare, consumes a lot of raw materials, and the cost price is much higher than that of sodium benzoate. In my opinion, if potassium sorbate can solve the problem of complicated production process and high cost price, potassium sorbate with better performance will gradually replace sodium benzoate and become a more suitable food additive for daily use.
