The most reliable food source for thousands of years in the Mediterranean region is the olive tree (olea europaea). The olive tree, a present from goddess Athena to the Greeks, spread all over the region with the temperate climate, due to its easy propagation by the branch or the seed in the olive fruit.
Around the Mediterranean, different countries have different unique cultivations.
Table olives are a Greek product, very important in the Mediterranean diet. Their phenolic compounds, contain very important biological properties and provide us with great health benefits.
The phenolic fraction of table olives varies in quality and quantity of phenolic compounds, depending on the cultivation and processing methods.
The table olives contain high amounts of hydroxytyrosol, tyrosol and oleanolic acid. The phenolic compounds in olives are oleuropein, ligstroside and verbascoside which are loosing their contents during the maturity of the olive fruit and give elevation to hydroxytyrosol.
There are three methods of processing table olives: http://www.theolivesgift.com/table-olives/
The processes decrease the phenolic content.
The poly-phenols are the most important antioxidants in our diet and are natural. They protect the body against oxidative stress and indeed are protective agents against diseases. The intake of extra virgin olive oil, very rich in poly-phenols, is very beneficial to health, because their antioxidant activity lowers risk of heart diseases.
There have been studies in Harokopio University, Athens, Greece, about the total antioxidant capacity AC (antioxidant capacity) of the olives and the drupe extracts of the black olives are higher in the antioxidant activity than the green olives, which are lower.
There are about five types of Greek olives available in the market. From each type of olives a small quantity was picked, and the flesh was separated from the pit with a small sharp knife. The flesh and the pit were weighed separately, to estimate the flesh to pit ratio and was freeze dried overnight. The fat in the dry flesh and pit was determined and the flesh percentage was 76%-82% and the pit percentage was 14%-24%. The percentages were different in every variety. On the other hand the poly-phenol content was the same for the flesh and for the pit, with the exception of the variety of the Cretan Thrubes, which contained the highest poly-phenols in the flesh and the lower in the pit.
Regardless of the type of olives, the results are the same. Table olives are a very good source of poly-phenols. The concentrations of poly-phenols in table olives vary according to the type of olive. Consuming about 10 olives daily, provides about 40 mg of poly-phenols from the flesh.
Hydroxytyrosol and tyrosol are the main poly-phenols and with a considerable increase of olive consumption, other poly-phenols found in the blood and urine, as phloretic acid, vanillic acid, ferulic acid, caffeic acid etc.
Documented health benefits of table olives have been reported, but very little is known and more studies are in the process.