Commonly used organic preservatives:
Benzoic acid (BA) Benzoic acid
Sorbic acid (SA) Sorbic acid
Dehydroacetic acid (DHA) Dehydroacetic acid
Hydroxybenzoic acid
P-hydroxybenzoate p-hydroxybenzoate
Ethyl p-hydroxybenzoate
Propyl p- hydroxybenzoate
Butyl p- hydroxybenzoate
Isopropyl p-hydroxybenzoate
Isopropyl p- hydroxybenzoate
Isobutyl p-hydroxybenzoate
Salicylic Acid
Hydroquinol
Question two. What are the names of preservatives and their respective descriptions Preservatives [fáng fǔ jì]
Preservatives are natural or synthetic chemical compounds that are added to foods, medicines, pigments, biological specimens, etc. to delay spoilage caused by microbial growth or chemical changes. Nitrite and sulfur dioxide are among the commonly used preservatives. The main role of preservatives is to inhibit the growth and reproduction of microorganisms in order to prolong the preservation time of food and inhibit the material corruption of the agent. Food preservatives can inhibit microbial activity, prevent food spoilage, thereby extending the shelf life of food. Preservatives are food additives used to maintain the original quality and nutritional value of food. The preservatives used are benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, calcium propionate and 25 other preservatives.
Chinese name
Preservatives
Role
Delay the growth of microorganisms that cause spoilage
Commonly used
Nitrite and sulfur dioxide
Purpose of use
Maintaining the original quality and nutritional value of the food
Principle
Principles of preservatives preservatives are as follows. There are three kinds of preservatives:
First, it is to interfere with the enzyme system of microorganisms, destroy their normal metabolism and inhibit enzyme activity.
Second, it is to make the microbial protein coagulation and denaturation, interfere with its survival and reproduction.
Third, it is to change the permeability of the cell plasma membrane, inhibit the exclusion of enzymes and metabolites in its body, leading to its inactivation.
Use of standards
When it comes to preservatives, people often think that harmful, in fact, in the safe use of the range, the human body is non-toxic side effects. China's use of preservatives have strict regulations, preservatives should meet the following standards:
Reasonable use of harmless to humans;
Does not affect the digestive tract flora;
In the digestive tract can be degraded to the normal composition of the food;
Does not affect the use of drugs and antimicrobial agents;
No harmful components of the food heat treatment.
China has so far approved the use of 32 kinds of food preservatives, of which the most commonly used are sodium benzoate, potassium sorbate and so on. The toxicity of sodium benzoate is stronger than potassium sorbate, and in the same value of acidity under the inhibition of bacterial effectiveness is only 1/3 of sorbic acid, so many countries gradually use potassium sorbate. However, because of the low price of sodium benzoate, it is still commonly used in our country, mainly used in carbonated drinks and fruit juice drinks. Potassium sorbate has strong antimicrobial power and low toxicity, and it can participate in the normal metabolism of human body and be transformed into CO2 and water. From the development trend of preservatives, biological preservatives made of biological fermentation will become the future development trend.
Briefly introduce the product performance, anticorrosive mechanism and scope of use of commonly used preservatives in China.
Compound pastry preservatives
1, benzoic acid and its salts, white particles or crystalline powder, odorless or slightly benzoin odor. Its antiseptic best PH 2.5-4.0, in the PH5.0 above the product, the bactericidal effect is not ideal. Because its safety is only equivalent to 1/40 of potassium sorbate, Japan has completely banned its application in food.
2, sorbic acid and its salts, white crystalline powder or slightly yellow crystalline powder or scale. Potassium sorbate is an acidic preservative with high antimicrobial properties, inhibit the growth and reproduction of mold, which is mainly through the inhibition of microbial dehydrogenase system in the body, so as to achieve the inhibition of microorganisms and play a role in preservation. It has inhibitory effect on bacteria, mold and yeast. The anticorrosive effect is significantly higher than benzoic acid class, is 5-10 times of benzoate. The toxicity of the product is low, equivalent to half of table salt. Its anticorrosive effect is weakened with the rise of PH, and the best anticorrosive effect is when PH=3. It still has the ability to inhibit bacteria when PH value reaches 6, but the lowest concentration cannot be lower than 0.2%. The toxicity is smaller than Nipogin ester. In our country can be used in soy sauce, vinegar, pasta sauce class, beverage, jam class.
3, dehydroacetic acid and sodium salts, dehydroacetic acid and its sodium salt are white or light yellow crystalline powder, light and heat stable, degraded to acetic acid in aqueous solution, non-toxic to humans. It is a broad-spectrum preservative with strong inhibitory effect on bacteria, mold and yeast in food. Widely used in meat, fish, vegetables, fruits, beverages, pastries and other antiseptic preservation.
4, Nipagin esters (i.e., parabens), the products are methylparaben, ethylparaben, propylparaben, butylparaben and so on. Among them, butyl paraben has the best antiseptic effect. Our country mainly uses p-hydroxybenzoic acid ethyl ester and propyl ester. The most used preservative in Japan is butyl paraben. The preservative mechanism of nipagin esters is: to destroy the cell membrane of microorganisms, so that the protein inside the cell is denatured, and can inhibit the activity of cellular respiratory enzyme system. Antibacterial active ingredient of nipagin ester is mainly the molecular state plays a role, due to its molecular hydroxyl group within the esterification, no longer ionized, PH value of 8 when there is still 60% of the molecule exists. Therefore, nipagin ester has good effect in the range of PH4-8. Not with P ...... >>
Question 3: What is the chemical name of the "preservative"? Preservatives There are many kinds of preservatives, the more is mainly to absorb the moisture in the product to prevent rotting and mold calcium carbonate can better absorb the moisture in the air is more commonly used
Question 4: What is the chemical name of the preservative? 1. Preservatives are an important class of food and other additives to the commonly used organic acids, organic small molecules, peptides preservative mechanism of action of the progress of the research is introduced, and explains the microbial adaptation to the reasons for the emergence of.
2. Food is rich in nutrients and highly susceptible to microbial contamination and spoilage. In order to ensure the safety of food consumption, people have adopted many methods to preserve food, such as salting, canning, refrigeration and so on. But under certain conditions, with the use of preservatives as an auxiliary means of preservation to prevent the corruption of food has a significant effect, so preservatives rely on one of the important food additives in the food industry is widely used
3. According to the nature of the main role of the antimicrobial antimicrobial agent can be broadly divided into bactericidal bactericidal agent with bactericidal effect and bacteriostatic inhibition of bacterial inhibition only. Bactericidal or bacteriostatic, there is no absolute boundary, often not easy to distinguish. The same substance, high concentration can be bactericidal, and low concentration can only be bacteriostatic, the effect of a long time can be bactericidal, the effect of a short period of time can only be bacteriostatic. In addition, due to the different nature of various microorganisms, the same substance has a bactericidal effect on one type of microorganisms, while another type of microorganisms may only have a bacteriostatic effect. It is generally believed that the inhibitory effect of food preservatives on microorganisms is realized by affecting cellular sub-structures, which include cell walls, cell membranes, enzymes related to metabolism, protein synthesis systems and genetic material. Since each substructure is necessary for the organism, the food preservative can achieve the purpose of bactericidal or bacteriostatic as long as it acts on one of the substructures
4. Commonly used are acetic acid, lactic acid, benzoic acid, and sorbic acid, which are inhibitory to bacteria and fungi
5. In solution, the weak acid is in a dynamic equilibrium between the dissociated and non-dissociated states at different pHs. In the case of low pH the preservatives have the greatest bacteriostatic activity, because most of the molecules in this time in the un-ionized state, un-ionized organic weak acid molecules are lipophilic, and therefore can be free to pass through the protoplasmic membrane. After entering the cell, in the high pH environment, the molecules dissociate into charged protons and anions, not easy to cross the membrane and accumulate in the cell. Preservative molecules continue to diffuse into the cell until it reaches equilibrium, causing the loss of control of intracellular H+, changing the intracellular pH status and accumulation of toxic anions, inhibiting the cell's basic metabolic reactions, and ultimately achieving the purpose of bacterial inhibition. Bacterial adaptation to weak acids is usually inherent rather than induced. the cell wall of G+ bacteria only has a peptidoglycan layer, and the cell wall of Bacillus megaterium trophozoites can pass through 30,000D molecules, so it is very easy for preservatives to enter the interior of these cells, i.e., the cell's intrinsic adaptation is also weak. the adaptation of G- bacteria is more complicated because they have an inner and outer wall. The outer wall layer (lipopolysaccharide layer) plays a very crucial role in controlling the affinity of the cell for preservatives or other small molecules. In many cases, bacteria can also be induced to develop adaptations, e.g., E. coliO157:H7 can develop some resistance to benzoic acid by inducing an acid-tolerant response after treatment with strong acidic conditions at pH 2.0. Some G+ bacteria, such as Listeria monocytogenes, can greatly enhance their acid resistance at pH 3.0 after being placed under mildly acidic conditions at pH 5.0. It is hypothesized that the cells have a complex acid-tolerant defense system that allows them to survive at low pH. Fungi are similarly adapted to organic weak acids. Adaptation studies in yeast suggest that possibly the cell membrane H+-ATPase and the transferor Pdr12 play an important role by expelling intracellular H+ and preservative anions from the cell, respectively, thus maintaining normal cellular metabolism.2 Hydrogen peroxide The lactoperoxidase system has been found to have strong antimicrobial effects in milk against both bacteria and fungi, and many G+ and G- bacteria can be inhibited by the lactoperoxidase system, with G- usually being more sensitive than G+. The system can exert maximum activity in the presence of hydroperoxides and thiocyanates. In the past, hydrogen peroxide was also added directly to food products, but due to too much damage to VC, it is now seldom used directly in food products, but is mostly used for the sterilization of packaging materials. Under the right conditions, hydrogen peroxide can produce reactive singlet oxygen, which has a very strong biological lethal effect. In addition, superoxide radicals generated during the incomplete reduction of molecular oxygen, with hydrogen peroxide and trace metal ions (e.g., Fe ...... >>
Question 5: Chemical name of the preservative 35%~40% formaldehyde solution
Commonly known as, formalin
Commonly used language for the embalming of animal carcasses
Volatile *** odor
Commonly used by medical colleges for the preservation of human specimens
Or to make specimens of animals