It's olive harvest season in Italy. See how the preserve is made
Preserved olives are practical, tasty and serve as an ingredient for several typical dishes. As snacks, fillings for pies and pies, codfish, pizzas, salads, whether black or green, in glass or in bulk, they are easily found in supermarkets. But how are preserved olives made?
Tourists arriving in Italy are fascinated by the olive trees – planted in many homes, such as symbol of victory and peace.
Next to the Colosseum in Roma, for example, there are several olive trees on the sidewalks. Curious people pick up the fruit and try to eat it.
The experience is quite unpleasant: an olive fresh from the tree is super bitter. And this has a chemical explanation.
Fresh olives have 14% of their total weight formed by a bitter compound called oleuropein, which results in an extremely bitter and bad taste on our palate.
An olive needs to be cured before we can consume it.
How are preserved olives made?
After harvesting, cleaning, sorting and sizing the olives, the simplest method to remove oleuropein from green olives is immersion in water for at least a week with daily liquid changes. Only then, if they are no longer bitter, can they be immersed in a brine solution – for conservation.
A similar method already allows olives to be tanned in brine. The principle is similar, but in this case, the fruits are immersed in a water and salt solution for a week, without changing them. At the end of the process, the brine is exchanged for another, saltier one.
A process that uses sodium hydroxide It made olive curing more agile and standardized. It was invented in California, in the United States, and is still used today by large industries. We owe his invention to the export of the product to more distant places due to the high preservation power of the fruits.
And how does this Californian process work? Sodium hydroxide accelerates the chemical gradation of the bitter oleuropein and makes the olive taste pleasant and ready for consumption in less than a week of processing.
After the olives are cured, there is a fermentation process that can last from three to six months. In green olives, lactic fermentation occurs due to the action of bacteria; In black olives, salt concentrations do not allow the development of many microorganisms.
The next stage is the packaging phase which occurs with heat treatment (sterilization and pasteurization) helping with conservation. The olive is ready for consumption!
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