The acidity of an oil is the quantity of free fatty acids, which are formed as a result of lipolysis, expressed in grams of acid oleico/100 grams of oil.
Lipolysis is a hydrolysis reaction that affects the structure of triglycerides and consists in breaking the bond between the glycerol and fatty acids esterified by it. This reaction is performed by an enzyme naturally present in the oil, the lipase in the presence of water. When the olives are damaged, the lipase and the water content in the cell are in contact with the oil operating the hydrolysis of triglycerides with release of free fatty acids.
The main consequence of this phenomenon is the increase of the free oil. The free acidity
dipente the quality of the olives used for oil production. The use of damaged or heavily affected by olive fly (Bactrocera oleae), collection techniques and adhere to time-optimal (naturally ripe olives fruit drop and leave the network, or worse, on the ground for several days), the prolonged stay of the olives before processing are all contributing factors to degrade the olive pulp and then increasing the free fatty acid content of oil until it is inedible.
During storage, however, the acidity may increase if the oil is left in contact with the sludge, because these sediments contain water and enzymes. Depending on the acidity
During storage, however, the acidity may increase if the oil is left in contact with the sludge, because these sediments contain water and enzymes. Depending on the acidity
virgin olive oils are classified as:
Extra virgin olive oil: free acidity more than 0.8 g per 100 g
Virgin olive oil: acidity free up to 2 g per 100 g of olive oil
clear: free acidity greater than 2 g per 100 g
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