Lecture 3: Peroxide value

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C. Olive oil Quality2. Olive oil categories and
types

• 3. Peroxide value

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Peroxide value (part I)

• It measures the oxidation state of the oil, by
  determining the concentration of peroxides in the
  sample
• The peroxides are primary oxidation compounds
  that occur during processing and storage of oil,
  as a consequence of the presence of oxygen
• In a second stage of oxidation, the peroxides
  decompose in different final products of
  oxidation

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Peroxide value (part II)

• The peroxide value, as well as acidity, are used
  to determine the categories of oil
• To classify an oil as extra virgin, the maximum
  peroxide value must not exceed 20 kilograms per
  kilo for olive oil

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Peroxide value

• it identifies the early stages of oxidation
• subsequent oxidation is detected through UV
  absorbance and by the oils sensory properties,
  such as rancidity, which result from the
  peroxides breakdown

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Olive oil oxidation and peroxides(ß?.
ß?ß?????af?a Olive oil analysis)
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Factors that increase the peroxide value (part I)

• High temperatures, visible light and oxygen.
• Contact with metal surfaces, such as copper, can
  also
• catalyse oxidation of the oil.

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Factors that increase the peroxide value (part
II)

• Damage to fruit and delays between harvest and
  processing are also a risk. Oil should be stored
  in cool, inert vessels, such as stainless steel
  or glass, away from the light.
• Oxygen should be removed by sparging with
  nitrogen prior to sealing the vessel

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Olive oils with Low Peroxide value

• apply good practices in the cultivation,
  harvesting, storage, and extraction of olive oil
  production, preventing the enzymatic oxidation
• protect the oil from light, heat, air and trace
  metal elements, avoiding chemical oxidation

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Quality criteria and Peroxide value
Extra virgin olive oil Virgin olive oil Ordinary olive oil Lampante Virgin olive oil Refined olive oil
Peroxide value lt 20 lt 20 lt 20 No limits lt 5
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Summary of 3th Lecture

• Peroxide value
• Factors that increase peroxide value
• Quality criteria and peroxide value