Most of the black olives sold in stores can be colored using a chemical process

By: Trademagazin Date: 2025. 12. 10. 10:46

🎧 Hallgasd a cikket: Nyelv: Sebesség: 1.05×

Few people know that black and green olives are different stages of ripeness of the same fruit – however, the picked berry is extremely bitter when raw, so its industrial processing is inevitable.

In large-scale production, the compound responsible for the bitter taste, called oleuropein, is typically extracted with an alkaline sodium hydroxide solution. This process also removes the dark color of the ripe berries.

The vast majority of black olives available on the market (nearly 99%) get their characteristic shade afterwards: manufacturers use an oxidation process, often with the addition of iron gluconate (E579). The fact of coloring must also be indicated on food labels: if we see that it is “colored by oxidation process”, we can be sure that the color of the berries is not the result of a natural ripening process.