Calcium Hydroxide (Hydrated Lime)

Description

Chemical Profile
Calcium hydroxide, commonly referred to as hydrated lime or slaked lime, is a chemical compound with the molecular formula Ca(OH)₂.

This white, odourless powder is produced through the chemical reaction of quicklime (calcium oxide) with water, a process known as slaking.

Physical and Chemical Characteristics
The compound exhibits limited solubility in water, forming a strongly alkaline solution called lime water. When exposed to carbon dioxide, calcium hydroxide undergoes a reaction that produces calcium carbonate.

Food Industry
Calcium hydroxide is a food-grade compound used in specific culinary and food processing applications. One of its most well-known uses is in the traditional preparation of nixtamalized corn, where it helps loosen the hulls of corn kernels to make masa for tortillas and tamales. It is also used in the production of hominy grits, the clarification of sugarcane juice during sugar production, and as a firming agent for fruits and vegetables in pickling. Only food-grade calcium hydroxide is suitable for such purposes, and it must be handled carefully in accordance with food safety regulations to ensure its safe and effective use.

Other Industrial and Commercial Applications
Widely used across various industries, calcium hydroxide plays a key role in construction for making mortar, plaster, and cement, and in agriculture for neutralizing acidic soils. It is also used in water treatment to remove impurities and adjust pH levels and in food processing as a food additive to regulate acidity.

Safety and Handling
Despite its widespread utility, calcium hydroxide is a caustic substance that demands careful handling. It can cause skin and eye irritation, and ingestion can be dangerous. Always wear protective gear when handling calcium hydroxide and follow safety guidelines.

Key Features

Key Features of Calcium Hydroxide for Food:

  • Alkalinity: Calcium hydroxide’s alkaline properties can be used to neutralise acids in food processing.
  • Humectant Properties: In some applications, it can help retain moisture in food products, improving their texture and shelf life.
  • Firming Agent: It can be used to firm the texture of certain food items, such as vegetables and fruits.
  • pH Regulator: By adjusting the pH level, calcium hydroxide can influence the growth of microorganisms and the activity of enzymes in food.

It is crucial to note that calcium hydroxide should only be used in food preparation under strict guidelines and with food-grade quality. Excessive or improper use can lead to food safety concerns, such as botulism.

Applications

  • Agriculture: Neutralizes acidic soils improve fertility and used as a disinfectant to control pests and diseases.
  • Chemical Industry: Used in the production of various chemicals, including calcium carbonate and bleach.
  • Construction: Used in mortar and plaster to bind bricks and stones, or concrete to improve workability and durability and acts as a pH regulator in soil stabilisation.
  • Water Treatment: Removes impurities from water by precipitation and adjusts pH in wastewater and drinking water.
  • Food Industry: Used in nixtamalization for corn and as a food additive (E526) to regulate acidity.