It's not that Zhang Jiashi doesn't want to make luncheon meat, or he directly says that it is canned, but the packaging of canned food is not a problem for the current scientific and technological level of the Qin Empire. Pen, Fun, Pavilion www.biquge.info Novel ww

For example, iron sheets, pull rings or something, you only need to improve the existing hydraulic or animal power press, and you only need to work some details.

And the raw materials are also not too big a problem, but the cost or something, it is still more cost-effective to have luncheon meat and the like.

After all, the current Qin Empire is more animal oil in terms of cooking oil, and in this case, if you want to make a canned meat made with oil bubbles, you need a lot of oil. In addition, animal oil is prone to spoilage, and it is difficult to store canned meat in oil foam for a long time until there is a sufficient level to make a qualified sealed iron can.

Therefore, in the production of canned food, Zhang Jiashi is very clear that if you want to make a breakthrough in this exhibition, you must produce a substance.

And this substance is sodium nitrite, which is known as a food preservative.

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Sodium nitrite itself has a certain toxicity, but for canned meat, sodium nitrite is a very important substance.

In later generations, sodium nitrite has two main functions: one is to protect the color, maintain the bright color of the food, so that the color of the food will not become darker and lighter. It is used for marinating meat foods. Second, it can inhibit Bacillus botulinum and prevent fresh meat from being gradually oxidized into gray-brown denatured myoglobin in the air, so that meat products can remain bright red.

Bacillus botulinum is an important factor causing meat spoilage, and the appearance of sodium nitrite can be said to play a great role in this aspect.

The pure purification of sodium nitrite is a sign of industrialization that there are two main ways to make sodium nitrite in later generations, one is to combine nitrite of alkali metal and alkaline earth metal, which can be obtained by the equivalent amount of nitric oxide and nitrogen dioxide into the hydroxide solution of the metal.

The second is to break down nitrate to produce nitrite and oxygen.

Nitrate, a general term for a class of inorganic compounds. It mainly refers to sodium nitrite, which is white to light yellow powder or granular, slightly salty in taste, and easily soluble in water.

Nitrates and nitrites are widely found in the human environment and are the most prevalent nitrogenous compounds in nature. Nitrate in the human body can be reduced to nitrite, a precursor substance of N-nitroso compounds under the action of microorganisms.

The appearance and taste are similar to table salt, and it is widely used in industry and construction, and it is also allowed to be used in limited quantities as a coloring agent in meat products. The incidence of food poisoning caused by nitrite is high.

Therefore, Zhang Jiashi is looking for a processing method for food preservatives that can be made at the moment.

After all, it is obvious that at this time, sodium nitrite or nitrite is not a salt product that can be mass-produced at this time.

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Preservatives refer to natural or synthetic chemical ingredients that are used to add food, medicines, pigments, biological specimens, etc., to delay microbial growth or chemical changes.

Nitrite and sulphur dioxide are commonly used preservatives.

The main function of preservatives is to inhibit the growth and reproduction of microorganisms, so as to prolong the storage time of food, and inhibit the substance. Food preservatives can inhibit microbial activity and prevent food** from spoiling, thereby extending the shelf life of food. Preservatives are food additives used to maintain the original quality and nutritional value of food.

The preservative principle of preservatives is roughly as follows: First, it interferes with the enzyme system of microorganisms, destroys their normal metabolism, and inhibits the activity of enzymes. Second, it is to coagulate and denature the proteins of microorganisms, interfering with their survival and reproduction. Third, it changes the permeability of the cell plasma membrane, inhibits the elimination of enzymes and metabolites in the body, and causes it to lose its activity.

There are five main standards for food preservatives in later generations: rational use is harmless to the human body, does not affect the digestive tract flora, can be degraded into normal components of food in the digestive tract, does not affect the use of drug antibiotics, and does not produce harmful ingredients during heat treatment of food.

Among these five categories, the most common ones are ****** sodium, potassium sorbate, etc.

Sodium is the sodium salt of ******. Sodium is an acidic preservative, which has a good preservative effect in an acidic environment, and is a very commonly used food preservative, which has the effect of preventing spoiled acid and prolonging the shelf life, and is widely used in countries around the world. However, in recent years, concerns about its toxicity have limited its use, and some countries, such as Japan, have stopped producing ****** sodium and restricted its use.

Sodium is mostly white particles, odorless or slightly with benzoin smell, slightly sweet taste, astringent; soluble in water 53.og\/1oom1, pH is about 8; ******sodium is also an acidic preservative, no bactericidal and bacteriostatic effect in alkaline medium; the best pH for preservative is 2.5-4.O, and the sterilization effect of 5% solution is not very good at pH5.O. Sodium is lipophilic, easy to penetrate the cell membrane into the cell body, interfere with the permeability of the cell membrane, inhibit the absorption of amino acids by the cell membrane, enter the cell body ionization acidification of the alkali storage in the cell, and inhibit the activity of the cell's respiratory enzyme system, prevent the condensation reaction of coenzyme A, so as to play the purpose of food preservation.

In later generations, the industrial method of producing ****** sodium is toluene in the presence of cobalt naphthenate catalyst, which is first ******prepared by air oxidation, and then ****** is used as raw material, neutralized with sodium bicarbonate, decolorized with activated carbon, and then filtered, dried and crushed to obtain the product.

Well, in this regard, Zhang Jiashi himself is not to think about it......

Sodium is widely used as a preservative in food processing and preservation, and is used in limited amounts in some foods in some countries. Because in food, ****** can volatilize in the free state, so the effect is better in strong acid food. It is generally used in carbonated drinks, soy sauce, sauces, candied fruits, fruit and vegetable beverages, etc., ****** can be used with p-hydroxy ******esters in soy sauce and beverages to increase efficiency. It is often used to preserve high-acid fruits, jams, beverage syrups and other acidic foods when it is used to preserve high-acid fruits, jams, beverage syrups, ******and other acidic foods, and can be combined with low-temperature sterilization to play a synergistic role.

and ****** sodium are generally limited to foods with high protein content. Sodium has the same effect on microorganisms as ******, but because it is a sodium salt, the amount required to achieve the same bactericidal effect as ****** is 1.2 times that of ******.

According to the US FAO regulations, ****** and ****** sodium can be used for frozen fish sticks, fish pieces, and fish stuffing products, but meat products are not included in the scope of use.

In addition, in the countries listed above where the use of ****** and ****** sodium is permitted, these two additives are not recommended as preservatives for meat products.

This means that ****** sodium is not a preservative of choice for meat products. This means that ****** sodium cannot inhibit the ** effect of botulinum toxin on meat.

The acute toxicity of sodium is small, and the maximum non-effect of the animal is measured as body weight.

However, it can be converted into a more toxic ****** in the acidic environment of the human intestine. Ingestion of ****** and its sodium salts in mice can lead to weight loss, diarrhea, initial bleeding, paralysis and even death. Toxicity is achieved by changing the permeability of the cell membrane, inhibiting the absorption of amino acids by the cell membrane, and inhibiting the activity of enzymes such as lipase through the cell membrane, which is achieved by the blockage of ATP synthesis.

There is no chronic toxicity. The rats were fed ****** for 8 consecutive weeks, and the results showed that there were no abnormal changes in the growth, reproduction and morphology of the mouse offspring. Other experiments have also shown that ****** has no accumulative, teratogenic, carcinogenic and mutagenic and antigenic effects.

It will be quickly degraded in animals, ****** mainly combined with glycine to form hippuric acid, and the rest combined with glucuronic acid to form 1-benjia preglucuronic acid.

Although sodium is relatively safe, for Zhang Jiashi, it is also impossible to make, and because this preservative has no preservative effect on meat, it is not considered.

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In later generations, a recognized safe preservative was sorbate, of which potassium sorbate was the most common.

Sorbic acid is a high-efficiency and safe preservative recommended by the International Food and Agriculture Organization and the World Health Organization, which is widely used in food, beverage, tobacco, pesticide, cosmetics and other industries, as an unsaturated acid, and can also be used in resin, spice and rubber industries.

Sorbic acid and potassium sorbate are good food preservatives,

This thing has been widely used in Western countries in later generations, but it is not widely used in China.

As a recognized safe and efficient antiseptic food additive, sorbic acid and potassium salt are bound to become more and more widely used in China's food industry. It is a white or yellowish-white crystalline powder, with a special odor. This product is soluble in ethanol, soluble in ****, and very slightly soluble in water. When we buy packaged (or canned) food, we often see the words "sorbic acid" or "potassium sorbate" in the ingredients, and people often mistakenly think that it may be the ingredient of the fruit "pear".

Sorbic acid is an unsaturated fatty acid, known as sorbicacid, also known as 2,4-hexadienoic acid and 2-propenylacrylic acid. Like other naturally occurring fatty acids, sorbic acid participates in metabolic processes in the human body and is digested and absorbed by the body to produce carbon dioxide and water.

In terms of safety, sorbic acid is an internationally recognized safe (GRAS) preservative with a high level of safety. The Food and Agriculture Organization of the United Nations, the World Health Organization, and the US FDA have all affirmed its safety. The toxicity and side effects of sorbic acid are lower than those of ******, vitamin C and table salt, and the toxicity is only 1/4 of ****** and half of that of table salt.

Sorbic acid does not have carcinogenic and teratogenic effects on the human body. Since the solubility of sorbic acid in water is not very high, it affects its application in food. Therefore, food additive manufacturers usually make sorbic acid into potassium sorbate with good solubility to expand the application range of sorbic acid products. The preservative principle and preservative effect of sorbic acid and potassium sorbate are the same.

Sorbic acid (potassium) can effectively inhibit the activity of molds, yeasts and aerobic bacteria, and can also prevent the growth and reproduction of harmful microorganisms such as botulinum, staphylococcus, salmonella, etc., but it is almost ineffective against beneficial microorganisms such as anaerobic spores and acidophilus lactobacillus, and its inhibition effect is stronger than that of bactericidal effect, so as to effectively prolong the preservation time of food and maintain the flavor of the original food.

In terms of Zhang Jiashi's needs, potassium sorbate is undoubtedly the most suitable product. Because the preservative effect of sorbic acid is effective for meat:

In later generations, the use of sorbic acid preservative in meat products is roughly as follows:

Dried meat, dried sausages, smoked ham and other similar dried meat products can be soaked in a solution of potassium sorbate with a concentration of 5%-15% for 3o seconds.

Beef sausage, pork sausage, pork and beef mixed sausage: sorbic acid can be added in the meat chopping link according to the dosage of o.o5%-o.o8%, and after making sausages, spray potassium sorbate solution with a concentration of 5% on the surface of the sausage.

General meat: first add sorbic acid or potassium sorbate to the meat according to the dosage of O.O5%-O.1%, and then add fatty acid glycerides according to the dosage of O.O1%-O.5%. In addition, potassium nitrite and sodium hexametaphosphate are added to the meat.

Meat filling: Add sorbic acid according to the dosage of o.o8%-o.1%, or use a mixture of sorbic acid and potassium sorbate.

Cooked chicken: Soak cooked chicken in potassium sorbate preservation solution for 3o seconds, and then store it at 4C, which can keep it fresh for 2o days. The formula of potassium sorbate preservation solution is: 1o% citric acid, 6% potassium sorbate, 34% modified corn starch, 5o% water, and the pH value of the preservation solution is 3.2.

Fresh poultry meat: The preservative solution containing sorbic acid was sprayed on the surface of fresh poultry meat and stored at 7C, and after 18 days, the product did not deteriorate, while the control sample deteriorated after 5 days. The formula of the fresh-keeping solution is: 7o parts of propylene glycol containing 7.5% sorbic acid, 2o parts of water, and 1o parts of glycerin.

Fresh chicken thighs and chicken breasts: Soak chicken thighs and chicken breasts with a concentration of 1o% sorbic acid solution for 3o seconds, and in the case of 4C, they can be stored for 2o days, and the freshness time is twice that of the control sample.

There are two main ways to make sorbic acid:

Crotonaldehyde, malonic acid and pyridine were put into the reaction tank at one time, stirred at room temperature, slowly heated to 9oC, and maintained at 9O~1Ooc for about 5 hours. After the reaction is completed, it is cooled to below 1oC, acidified and decarboxylated, and sorbic acid is obtained. This is the earliest method of synthesizing sorbic acid, with a yield of about 3o%, and if calcium malonate is used instead of malonic acid, the yield can be improved.

Crotonaldehyde and ketene are reacted in a solvent containing a catalyst (equimolar ********, zinc chloride, green aluminum, boric acid and salicylic acid at 15 oC) and react around OC. Then sulfuric acid is added, the solvent is removed, heated at 8OC for more than 3 hours, and after cooling, the precipitated coarse crystals are recrystallized to obtain the product.

But for Zhang, these two ways of making ......

He could only say: This kind of thing, can it be made now?