What is the production process of calcium propionate?

Today, Jiangsu Aolikai Food Technology Co., Ltd. will introduce the content of calcium propionate to everyone. What is the production process of calcium propionate?

The production process of calcium propionate is not complicated. The core is an acid-base neutralization reaction - using propionic acid to neutralize calcium sources (calcium hydroxide or calcium carbonate) to produce calcium propionate, water, and carbon dioxide. However, every step from the laboratory to industrial mass production is meticulous.

1. Preparation of raw materials: Propionic acid + calcium source, both are indispensable

The two primary raw materials for calcium propionate are propionic acid (food-grade, with a content of ≥99.5%) and a calcium source. In industry, calcium hydroxide is a commonly used calcium source due to its fast reaction rate and high conversion rate. Calcium carbonate is also used, which has a lower cost, but the reaction releases a large amount of CO₂, which needs to be discharged in time to facilitate the reaction. In recent years, there have been studies on using waste materials such as egg shells and oyster shells as calcium sources. After being crushed, they can be directly involved in the reaction, which not only reduces costs but also turns waste into treasure.

II. Neutralization reaction: temperature and pH control are key

Prepare calcium hydroxide as a suspension or lime milk, and gradually introduce propionic acid while stirring. Maintain the reaction temperature between 70-100℃ and allow the reaction to proceed for 2-3 hours, with the final pH controlled at 7-8. If calcium carbonate is used, keep the temperature at 60-80℃ and react for the same duration. During the process, CO₂ will continuously evolve, which needs to be discharged through a condenser. The pH value at the end of the reaction directly determines the yield and purity of calcium propionate - a lower pH indicates an excess of propionic acid, while a higher pH indicates remaining calcium source.

III. Post-treatment: Three steps to finalize: filtration, concentration, and drying

After the reaction is complete, the unreacted solids and impurities are first removed through filtration or centrifugation. The filtrate is then sent to an evaporator for concentration until it becomes viscous, and subsequently transferred to a crystallization tank for slow cooling and crystallization. The crystallized calcium propionate undergoes centrifugal separation and washing, and finally, it is dried at 120~140℃ for 2~4 hours, crushed, and sieved to obtain the finished product. In the airflow drying process, the temperature of the hot air can reach 200℃, and the temperature at the material outlet is controlled at around 60℃ to prevent product decomposition.

IV. Natural calcium propionate: an additional fermentation process

If we want to produce "natural" calcium propionate (compliant with FDA and EU standards), the process is completely different: first, glucose or starch is fermented by propionibacterium to produce propionic acid, then the fermentation broth is neutralized with calcium hydroxide, and the subsequent purification, crystallization, and drying processes are consistent with chemical methods.

In a nutshell: The production process of calcium propionate essentially involves "acid-base neutralization + crystallization and drying". The technical threshold is not high, but each step, including temperature, pH, and drying conditions, directly affects the content and safety of the product. The industrial-grade calcium propionate requires a content of ≥98% and a free acid content of ≤0.5%. These indicators are all maintained through process parameters.