E529 – Calcium oxide
StabiliserDescription
Calcium oxide (Quicklime, CaO) is an odorless white powder used as an acidity regulator, firming agent, and processing aid (e.g., in refining sugars or clarifying brine). It is highly alkaline and reacts exothermically with water to form calcium hydroxide.
Notes
Calcium oxide, also known as quicklime, is a white, odorless powder made by heating limestone or chalk at very high temperatures (around 900°C). This process, called calcination, drives off carbon dioxide and leaves behind pure calcium oxide. It's essentially the same stuff that's been used for thousands of years to make mortar and plaster, but food-grade versions are specially purified for safe consumption. In food production, calcium oxide serves as both an acidity regulator (helping to control pH levels) and a firming agent that helps maintain texture. You'll find it used in processed foods where manufacturers need to adjust acidity or keep things crisp and firm. It's commonly used in pickled vegetables, some baked goods, and certain processed dairy products to maintain the right chemical balance and texture. This additive is completely synthetic in the sense that it's manufactured through an industrial process, though it starts from natural limestone. It's suitable for vegetarians and vegans, and there are no specific allergen concerns. However, it's a very alkaline substance, so food manufacturers must use it carefully in precise amounts - though by the time it reaches your plate, it has typically reacted with other ingredients and is no longer in its original caustic form.