Lecture 4: Qualitative characteristics of olive oil Part IV

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C. Olive oil Quality1. Olive oil composition and
quality

• 4. Quality characteristics of olive oil
• Part ?V

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Sterols (part I)

• sterols are an essential component of cell
  membranes, and both animals and plants produce
  them
• over 40 phytosterols have been identified so far
• the amount of total sterols in extra virgin olive
  oil found by different groups varies between
  113-265 mg/100g oil

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Sterols (part II)

• two factors influencing this amount are the
  cultivar and the degree of ripeness of the olives
  
• the major sterol in olive oil is ß-sitosterol,
  constituting up to 90-95 of total sterols
• campesterol and stigmasterol make up about 3 and
  1, respectively

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Sterols and cancer (part I)

• there are several reports on anti-tumor effects
  of phytosterols, especially ß-sitosterol
• ß-sitosterol appears to be effective in the
  treatment of benign prostatic hyperplasia. There
  have been reports on the health benefits of
  ß-sitosterol on colon cancer cells and breast
  cancer cells

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Sterols and cancer (part II)

• ß-sitosterol, might exert distinct
  anti-carcinogenic effects with regard to cancers
  of the prostate, colon, breast and stomach

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Tocopherols and vitamins (part I)

• Olive oil has in its composition the alfa, beta,
  gamma, delta tocopherols . Tocopherols are
  compounds with vitamin E activity, which is a
  natural antioxidant
• Olive oil also contains Vitamin A, D, B complex
  and K

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Tocopherols and vitamins (part II)

• These compounds are known to contribute to the
  antioxidant capacity of olive oil, as well as
  enhance oil stability during frying by protecting
  it from thermo-oxidative degradation

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Tocopherols and vitamins (part III)

• They increase oxidation stability of oils during
  storage due to preventing from the light
• a-tocopherol defends the body against free
  radical attacks, and prevents skin disorders,
  cancer and arteriosclerosis

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Omega-3 and Omega-6 acids (part I)

• Olive oil contains both Omega-3 and Omega-6 fatty
  acids, which are essential acids that cannot be
  made by the human body

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Omega-3 and Omega-6 acids (part II)

• Olive oil is generally 10 linoleic acid (omega-6
  oil) and less than 1 linolenic acid (omega-3
  oil)
• Omega-3 fatty acids are important in preventing
  cardiovascular disease

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Pigments and aromatic components (part I)

• The olive oil color is given by the pigments like
  chlorophyll, pheophytin, and carotenoids
• The presence of these components depends on
  several factors such as the fruit maturation, the
  cultivar, the soil and climate and the extraction
  procedures.
• The aroma and the taste components are the result
  of enzymatic reactions

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Pigments and aromatic components (part II)

• 280 compounds have been identified in the
  volatile fraction of virgin olive oils.
  Fruitiness, bitterness and pungency as well as
  undesired attributes are correlated to different
  volatile compounds of olive oil
• The color pigments and the flavor compounds
  increase the stomach secretion and help a better
  absorption of the natural antioxidants.

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Aromatic compounds

• aldehydes, terpene compounds
• there is a greater concentration of flavor
  components when olive changes color from green to
  violet black
• there is a reduction of aromatic components
  during storage of olive oil (enzyme action)

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Summary of 4th Lecture

• Sterols
• Tocopherols
• Omega-3 and omega-6 acids
• Aromatic compounds of olive oil