Industrial production of calcium propionate is obtained by neutralizing propionic acid with calcium hydroxide or calcium carbonate. White crystals, granules or crystalline powder, usually calcium propionate exists in the form of crystalline hydrate, food grade calcium propionate is generally calcium propionate monohydrate. Odorless or with a slight propionic acid odor. It is stable to light and heat, hygroscopic, easily soluble in water, and its aqueous solution is weakly alkaline. Under acidic conditions, it produces free propionic acid, has antibacterial effect, has inhibitory effect on Aspergillus niger and Bacillus aerophilus, and has no effect on yeast.
Calcium propionate is also an acidic bacteriostatic agent, which has inhibitory effects on yeast bacteria, molds, especially Aspergillus flavus and Gram-negative bacteria. Non-toxic (unless the dosage is too large), LD50 is 5100mg/kg. It can also provide energy itself. In many countries, it is used as a mold inhibitor for food and feed, and it can also be used as a mold inhibitor for silage under the condition of pH=4.0. The minimum inhibitory concentration (MIC) is 0.2%, and the MIC for Bacillus subtilis and Escherichia coli is 0.05%; generally, the amount should be increased by 8 to 10 times when the pH value = 6.0, and the general dosage can be achieved at 0.5%. mildew effect.
It is an international food and feed bacteriostatic agent approved by the Food and Agriculture Organization of the United Nations and the World Health Organization (FAO/WHO). Its toxicity is far lower than that of sodium benzoate, which is widely used in my country. As well as anti-mildew of jelly, soy products, processed meat products, wet grains and feed; it can also be used medicinally, and can be made into liquid, powder, paste, etc.; it also has a good therapeutic effect on skin diseases caused by mold.
Application
Preservatives, fungicides. Its bacteriostatic properties are the same as those of propionic acid. It can be used for bread, cakes, soy products, dumpling skins, wonton skins, raw cut noodles, etc. Usage and dosage: The recommended dosage is 0～2.5g/kg. According to the “Hygienic Standard for the Use of Food Additives” (GB2760-1996), it can be used in bread, vinegar, soy sauce, soy products, and cakes, with a maximum dosage of 2.5g/kg; raw noodle wet products (raw cut noodles, wonton wrappers, with a maximum dosage of 0.25 g/kg) g/kg (as propionic acid).
Matters needing attention: Calcium propionate is generally used in bread, and sodium propionate is used in cakes and pastries. Sodium propionate solution is alkaline, which inhibits yeast activity, delays dough fermentation, and also produces unfavorable flavors. The use of calcium propionate in bread also has the effect of strengthening calcium, which is conducive to the formation of gluten tissue. If calcium propionate is used in West Point, it will react with the baking soda (sodium bicarbonate) in the leavening agent to form insoluble calcium carbonate, which reduces the production of CO2. Therefore, sodium propionate is mainly used in West Point.
The main raw materials are propionic acid (food grade, content of more than 99.5%), quicklime (industrial grade, calcium chloride content of more than 95%), deionized water (arsenic and heavy metals are not required to be detected in the water). Neutralization reaction conditions: the reaction temperature is 70～90℃, the reaction time is about 2～3h, and the pH value of the reaction end point is 7～8. Concentration and crystallization process conditions The inlet temperature of heat transfer oil is 170-180°C, the outlet temperature is 120-130°C, and the flow rate of heat transfer oil is 6m3/h. Airflow drying process conditions Hot air temperature is 200°C, drying temperature is 120-130°C, material outlet temperature is 60°C, and air pressure is 4-5kPa.
A membrane chemical reactor is used to prepare a high-purity calcium propionate, and the preparation process generally includes the following steps: (1) First, put a certain amount of deionized water into the above-mentioned membrane chemical reactor, and then heat it at 50 to 80 ° C. At the same time, the input amount of solid calcium hydroxide and propionic acid is alternately put into the membrane chemical reactor in 4 to 10 batches according to the mass ratio of 1:3.5 to 3.7, that is, a batch of propionic acid is put in and then a batch of calcium hydroxide is put in. , in the process of inputting the last batch of calcium hydroxide, the pH value of the neutralizing solution was tested many times, and the feeding speed and feeding amount of the remaining calcium hydroxide were controlled according to the pH value, and the feeding was stopped when the pH value reached 6.4-8.0; (2 ) After feeding, the above reaction solution was kept at 70-80°C for 30-40min, and the pH value of the reaction solution was controlled to be 6.4-8.0; (3) After the reaction in the membrane chemical reactor was completed, press filtration, Crystallization, dehydration, and drying process to obtain calcium propionate powder.
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