Lecture 3: Qualitative characteristics of olive oil Part III

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C. Olive oil Quality1. Olive oil composition and
quality

• 3. Quality characteristics of olive oil
• Part III

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Polyphenols (part I)

• natural antioxidants that contribute to a bitter
  taste, astringency, and resistance to oxidation.

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Polyphenols (part II)

• they have been shown to have a host of beneficial
  effects from healing sunburn to lowering
  cholesterol, blood pressure, and risk of coronary
  disease

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Polyphenols (part III)

• hydroxytyrosol and tyrosol are some of the many
  phenol compounds in olive oil

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Properties of polyphenols (part I)

• phenolic compounds of olive oil have repeatedly
  been reported to be potent antioxidants
• there is a wide range of these components that
  show antioxidative properties, such as
  hydroxytyrosol, tyrosol, and oleuropein

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Properties of polyphenols (part II)

• phenolic compounds of extra virgin olive oil
  have a distinct anti-inflammatory effect
• oleuropein, inhibit platelet aggregation

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Factors affecting the polyphenol content (part I)

• Olive Varietal Koroneiki olives, for instance
  have a very high level of polyphenols, while
  Arbequinas content is low. The content of
  Frantorio olives is medium-high and that of
  Leccino medium
• Time of Picking Oil made from green (unripe)
  olives has more polyphenols than oil made from
  ripe olives. The polyphenol concentration
  increases with fruit growth until the olives
  begin to turn purple and then begins to decrease 

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Factors affecting the polyphenol content (part
II)

• Environmental Factors such as altitude,
  cultivation practices, and the amount of
  irrigation.
• Extraction Conditions Techniques used to enhance
  yield, such as heating the paste, adding water,
  and increasing malaxation time, result in a loss
  of polyphenols

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Factors affecting to polyphenol content (part
III)

• Storage Conditions The type of containers and
  the length of storing are key factors in the
  oils polyphenol content. As oil sits in storage
  tanks or in a bottle, the polyphenols will slowly
  be oxidized and used up
• Refining Refined oils are low in tyrosol and
  other phenols

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Hydrocarbons (part I)

• The major hydrocarbon in olive oil is squalene, a
  triterpene and intermediate product of the
  cholesterol biosynthesis pathway

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Hydrocarbons (part II)

• Extra virgin olive oil contains squalene in an
  amount of about 400-450 mg/100g, refined olive
  oil contains about 25 less, other hydrocarbons
  are also present, e.g., the pro-vitamin A
  ß-carotene, albeit in very small quantities
  (ß-carotene 0.03 - 0.36 mg/100g)

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Squalene (part I)

• It is a natural organic compound and an important
  metabolic factor
• It is part of the synthesis of cholesterol,
  steroid hormones, and vitamin D in the human
  body.

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Squalene (part II)

• it is also believed to have anti-cancer
  properties
• it has anti-neoplastic influence on the colon,
  breast, and prostate
• it seems to have immune-stimulating properties
  and it can inhibit the development of various
  tumors
• it has major protective effect against skin
  cancer

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Squalene and cancer (part I)

• a recent case-control study in Italy reported a
  significant inverse trend of edible oil (mainly
  olive oil) intake and risk of pancreatic cancer
• this protective effect might be due to the large
  amount of squalene in extra virgin olive oil

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Squalene and cancer (part II)

• the majority of studies have investigated the
  effect of topically applied or systemically
  administered squalene on chemically-induced
  cancers of the skin, the colon and the lung and
  the results clearly show that dietary squalene
  has distinct anti-carcinogenic effects

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Summary of 3rd Lecture

• Polyphenols
• Properties of polyphenols
• Hydrocarbons
• Squalene