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Product Overview
Potassium sorbate, also known as 2,4-hexadienoic acid potassium salt, is the potassium salt of sorbic acid, with the molecular formula C(6)H(7)O(2)K. It appears as white to light yellow crystalline flakes, crystalline granules, or crystalline powder, odorless or with a slight odor. When exposed to air for long periods, it can absorb moisture, oxidize, and decompose, leading to discoloration. It is easily soluble in water, and also dissolves in propylene glycol and ethanol. Often used as a preservative, it inhibits many enzyme systems by combining with the sulfhydryl groups in microbial enzyme systems, resulting in a much lower toxicity compared to other preservatives, and is widely used. Potassium sorbate exhibits strong preservative effects in acidic conditions, while its effectiveness is reduced in neutral environments.
The preservative mechanism of potassium sorbate is similar to that of sorbic acid, as it combines with the sulfhydryl groups in microbial enzyme systems, thereby disrupting many enzyme functions. Potassium sorbate effectively inhibits the activity of molds, aerobic bacteria, and yeast, and prevents the growth of microorganisms such as staphylococcus, botulinum, and salmonella. However, it is ineffective against anaerobic spore-forming bacteria and lactobacilli. Its primary function is to inhibit microbial growth rather than kill them, thereby extending the shelf life of foods while preserving their original flavor.
Production Process
There are two main methods for synthesizing sorbic acid, which is a precursor to potassium sorbate. The first method involves the reaction of crotonaldehyde with acetone under specific conditions. The second, more commonly used method, uses crotonaldehyde and ketene as raw materials, undergoing a reaction under specified conditions. Crotonaldehyde is primarily derived from the condensation of acetaldehyde, while ketene is produced by cracking acetic acid. The final product, potassium sorbate, is formed by reacting sorbic acid with potassium hydroxide. The reaction formula is as follows:
In terms of raw material preparation, tap water is deionized through an ion exchange system and stored in a reservoir for later use. Potassium hydroxide with 92% purity is diluted to 49% with deionized water in the alkali solution preparation tank. In the synthesis process, a specific amount of sorbic acid is added to the reaction vessel, followed by the vacuum extraction of deionized water into the metering tank, accounting for about 60% of the sorbic acid. The prepared alkali solution is then vacuum-pumped into the alkali storage tank, from where potassium hydroxide solution is gradually added into the reaction vessel to initiate the acid-base neutralization reaction. The temperature is controlled at around 40°C by circulating cooling water through the jacket of the reaction vessel. After 30 minutes, samples are taken, and the pH of the reaction mixture is measured using a pH meter. The addition of alkali is stopped when the pH reaches or exceeds 9.5. The reaction should be completed within 45 minutes. After 1 hour of stirring, the reaction mixture is transferred to a storage tank, vacuum-filtered, and the filtrate is stored in the storage tank. The activated carbon used for filtration can be regenerated and reused. The alkali solution is then concentrated in an evaporation tank using jacketed heating oil, ensuring the temperature is maintained at 40-50°C with a vacuum level of 0.1MPa. The concentrated solution is subjected to vacuum evaporation for 3-4 hours. Once technical standards are met, the temperature is raised to 70°C, and the solution is discharged to the centrifugation section. After dewatering in a three-legged centrifuge, the evaporated solution is centrifuged again to separate it into the first mother liquor. The first mother liquor undergoes further vacuum evaporation to produce a semi-finished product, which is then centrifuged again to yield the second mother liquor. The semi-finished product undergoes up to seven cycles of recovery before meeting the required standards. Finally, the material is unloaded from the centrifuge, dried at 105°C to meet product specifications, and sent to the packaging section for packing and storage.
Function and Effects
Preservative.
Applications
Potassium sorbate, being the least toxic food preservative, is widely used in the food and feed processing industries, as well as in cosmetics, cigarettes, resins, flavors, and rubber industries. However, its most extensive application is in food preservation and feed.
Animal Feed Industry:
The United States and the European Union have recognized potassium sorbate as a legal feed additive for animal feed. It effectively inhibits mold growth in feed, particularly the formation of aflatoxins, making it highly effective in preventing feed spoilage. It also maintains antimicrobial properties within the animal's digestive tract. Additionally, the neutral taste of potassium sorbate is suitable for use in feed, as animals are more sensitive to changes in taste than humans. As an unsaturated fatty acid, potassium sorbate can be digested as a feed component without causing any adverse effects on animals. Feed is prone to spoilage during storage, transportation, and sales, so the market potential for potassium sorbate in the feed industry is enormous.
Food Containers and Packaging Materials:
The purpose of food packaging is to protect the contents. Active materials are increasingly being used to enhance packaging functionality, not only extending the shelf life of packaged food but also maintaining its nutritional value and safety. China's 2009 GB 9685-2008 hygiene standards clearly specify the allowable amount of potassium sorbate that can be added to food containers and packaging materials, as well as the maximum residual levels of potassium sorbate. In plastic production, potassium sorbate can be used as needed; in rubber, the usage is 0.1%; and in paper, it is used according to production requirements, with no restrictions on residual sorbic acid levels.
In summary, potassium sorbate can be directly added, dipped, sprayed, or applied as a dry powder spray. Packaging materials can also be treated in various flexible ways. Given its properties, which are equivalent to natural substances, the application range and usage of potassium sorbate are expected to expand.
Food Preservative:
Potassium sorbate is widely used as a food preservative. China approved its use in 1982, with standards set for its concentration in flour products, pickles, canned goods, dried fruits, dairy products, and condiments, ranging from 0.02% to 0.1%. Adding 1% potassium sorbate to meat products significantly inhibits the production of botulinum toxin. Potassium sorbate is also widely used in low-alcohol beverages such as fruit wine, beer, and wine, with ideal preservative effects. The Food and Agriculture Organization (FAO) has set a maximum usage limit for potassium sorbate at 0.28/kg, and countries worldwide have established strict usage standards based on this guideline. Treating packaging materials with potassium sorbate extends the shelf life of bread and dried products. Due to the limitations of using single food additives and physical properties, the development of composite food additives is being vigorously pursued to achieve the best effects through synergy.
(1) Applications in Vegetables and Fruits:
Fresh vegetables and fruits quickly lose their luster and moisture if not promptly preserved, leading to surface wrinkles and easy mold formation, which results in unnecessary waste. By applying potassium sorbate preservative to the surface of vegetables and fruits, they can be stored for up to a month at temperatures as high as 30°C, while maintaining their green color. Apples sprayed with potassium sorbate preservative can be stored at room temperature for four months, with only about 5% showing signs of decay. Potassium sorbate can also prevent the oxidation and rusting of tinplate used in canned vegetable packaging.
(2) Applications in Meat Products:
Smoked ham, dry sausages, jerky, and other dried meat products can be briefly soaked in a suitable concentration of potassium sorbate solution to achieve preservation. For products like beef sausages and pork sausages, potassium sorbate can be added directly during the meat chopping process. After the final product is made, a 5% potassium sorbate solution can be sprayed on the surface to achieve preservation. Potassium sorbate can also be directly added to general meat products and minced meat for preservation
(2) Applications in Meat Products
Cured ham, dry sausages, jerky, and other similar dried meat products can be briefly soaked in a solution of potassium sorbate at an appropriate concentration to achieve preservation and freshness. For sausage products like beef or pork sausages, potassium sorbate can be added directly during the chopping process. Once the sausage is formed, a 5% potassium sorbate solution can be sprayed on the surface for preservation. Potassium sorbate can also be added directly to general meat mixtures or fillings for preservation. Fresh or cooked chicken can benefit from soaking in preservation solutions with different formulas and concentrations of potassium sorbate, which improves freshness and extends shelf life. Fresh poultry meat sprayed with potassium sorbate preservation solution significantly outlasts untreated samples, with preservation lasting twice as long.
(3) Applications in Aquatic Products
Adding 0.1% to 0.2% of a mixed preservative of sorbic acid and potassium sorbate to fish sausages allows storage at temperatures up to 30°C for two weeks without spoilage. Under the same conditions, untreated samples spoil within a week. When the temperature is maintained at 10-15°C and the pH of the fish sausage is kept below 6, the sausage can be stored for seven weeks without spoilage. Generally, fish cake products with a pH between 6.8 and 7.2 can be preserved using potassium sorbate or its mixture with sorbic acid. However, when using the mixture, it's crucial to control the proportion of sorbic acid because it is an acidic preservative, and in the low pH environment of fish cakes, it can affect their elasticity. To reasonably address this issue, the sorbic acid content in the mixture must be reduced. Dried fish products, which typically have a moisture content below 30%, are less prone to bacterial spoilage but are susceptible to mold. Adding a suitable amount of potassium sorbate to dried fish can effectively prevent mold. Smoked fish products can be preserved by spraying a 5% to 10% potassium sorbate solution before, during, or after the smoking process. Cooked fish and shrimp prepared with soy sauce can be stored at 10-15°C for two months without spoilage when potassium sorbate is added. Fresh fish, shrimp, or other seafood thoroughly cleaned and soaked in a potassium sorbate preservation solution for 20 seconds before refrigeration can have their shelf life significantly extended.
(4) Applications in Soy Sauce and Pickled Products
Adding an appropriate amount of potassium sorbate to soy sauce can prevent spoilage and mold growth for up to 70 days, even at high temperatures. For pickled products like beets, cucumbers, and other pickles, potassium sorbate can be added to vinegar containing salt for preservation. Typically, to avoid cloudiness in the brine of pickled products, spices, salt, and potassium sorbate are dissolved in water before adding vinegar. Kimchi can be preserved by directly adding a mixture of salt and potassium sorbate.
(5) Applications in Pastries
When using potassium sorbate as a preservative for pastries, it should first be dissolved in water or milk before being added directly to the flour or dough. For preserving starch-based foods with potassium sorbate, it's best to acidify the ingredients with a small amount of vinegar, as potassium sorbate is most effective as an antimicrobial preservative in environments with a pH below 5-6.
(6) Applications in Beverages
Potassium sorbate can be added to various beverages, including fruit and vegetable juices, carbonated drinks, and protein drinks, significantly extending the product's shelf life.
(7) Applications in Candied and Confectionery Products
Peanut candy, almond candy, and general filled candies can be directly preserved with an appropriate amount of potassium sorbate. For high-sugar-content candies, the amount of potassium sorbate should be appropriately increased to ensure effective preservation.
Packaging and Transportation:
Storage Conditions: This product should be sealed and stored in a cool, dry, and well-ventilated place, away from light and heat.
Packaging: Bulk: 25 kg/paper drum, Samples: 1 kg/aluminum foil bag. Custom packaging is available upon request.
Transportation: By courier or freight. Domestic courier arrives within three days, freight within five days. Quotes generally include domestic transportation costs.
Shelf Life: Two years
