Lecture 8: Criteria of olive oil authenticity

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C. Olive oil Quality2. Olive oil categories and
types

• 8. Criteria for olive oil authenticity

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Criteria for olive oil authenticity

• Detecting other vegetable oils
• Determination of the unsaponifiable fraction
• Determination of sterols
• Determination of other fatty acids
• Determination of trans fatty acids
• Determination of saturated acids in the b
  position of triglycerides

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Determination of the unsaponifiable fraction

• Its the total amount of non-glyceride components
  (sterols, aliphatic alcohols, dyes, hydrocarbons)
  
• Prices of unsaponifiable fraction in vegetable
  fats are low (0.3-1.5)
• high values ??indicate probability of adding
  mineral oil

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Determination of sterols (part I)

• Sterols main components of unsaponifiable
  fraction
• beta-sitosterol (a higher rate), D5-avenasterol,
  campesterol and stigmasterol

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Determination of sterols (part II)

• The determination of the sterol fraction is an
  important criterion for identifying the botanical
  origin of olive oil
• The presence of specific sterols in olive oil
  (brassicasterol, campesterol, stigmasterol,
  beta-sitosterol, total D7 and stigmasterol) above
  certain limits is indicative of adulteration.

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Limits for sterol composition in olive oils

• Cholesterol lt0.5 of total sterols
• Brassicasterol lt0.1 of total sterols
• Campesterol lt4.0 of total sterols
• Total beta-sitosterolgt 93.0 of total sterols
• D7- stigmasterol lt0.5 of total sterols
• Total sterols gt 1000 mg / kg

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Sterols and other oils

• Brassicasterol indicates the presence of
  rapeseed oil
• D7-stigmasterol indicates the presence of
  sunflower oil and safflower oil
• Cholesterol indicates the presence of animal
  fats
• Campesterol indicates the presence of rapeseed
  oil, sunflower oil, soybean oil, mustard oil,
  sesame oil and safflower oil

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Fatty acids

• There are two types of olive oil
• The first type of oil contains low
  linoleic-palmitic acid and high oleic acid
• The second type of oil contains high
  linoleic-palmitic acid and low oleic acid
• Greek, Spanish, Italian olive oils belong to the
  first category while Tunisian olive oil belongs
  to the second category

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Fatty acids and fraud

• Fatty acids that are mostly found in olive oil
  are oleic, linoleic, palmitic, stearic,
  palmitoleic
• Fatty acids that can help to detect olive oil
  fraud are linolenic, myristic, arachidic,
  behenic, lignoceric

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Fatty acid limits in olive oils
Fatty acids rate
Myristic lt 0,5
Palmitic 7,5-20,0
Palmitoleic 0,3-3,5
Stearic 0,5-5,0
Oleic 55,0-83,0
Licoleic 3,5-21,0
Arachidic lt 0,6
Behenic lt 0,2
Lignoceric lt 0,2
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Trans fatty acids

• Olive oil fatty acids are in the cis form
• The cis conversion of fatty acids into
  trans-fatty acids occurs in acute treatment
  conditions

Type of olive oil Trans C18 1 Total Trans C18 2 C18 3
Extra virgin olive oil lt 0,05 lt 0,05
Lampante max 0,10 max 0,10
Refined olive oil max 0,20 max 0,30
Olive oil max 0,20 max 0,30
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Summary of 8th Lecture

• Criteria for olive oil authenticity
• Sterol limits
• Fatty acid limits in olive oil