Codex Standard for Named Vegetable Oils (CODEX-STAN 210 - 1999)
Codex Standard for Olive Oil, Virgin and Refined and for Refined Olive-Pomace Oil (CODEX STAN 33-1981, Rev. 1-1989)
The Appendix to this Standard is intended for voluntary application by commercial partners and not for application by governments.
1. SCOPE
This Standard applies to the vegetable oils described in Section 2.1 presented in a state for human consumption.
2. DESCRIPTION
2.1 Product Definitions
(Note: synonyms are in brackets immediately following the name of the oil)
2.1.1 Arachis oil (peanut oil; groundnut oil) is derived from groundnuts (seeds of Arachis hypogaea L.).
2.1.2 Babassu oil is derived from the kernel of the fruit of several varieties of the palm Orbignya spp.
2.1.3 Coconut oil is derived from the kernel of the coconut (Cocos nucifera L.).
2.1.4 Cottonseed oil is derived from the seeds of various cultivated species of Gossypium spp.
2.1.5 Grapeseed oil is derived from the seeds of the grape (Vitis vinifera L.).
2.1.6 Maize oil (corn oil) is derived from maize germ (the embryos of Zea mays L.).
2.1.7 Mustardseed oil is derived from the seeds of white mustard (Sinapis alba L. or Brassica hirta Moench), brown and yellow mustard (Brassica juncea (L.) Czernajew and Cossen) and of black mustard (Brassica nigra (L.) Koch).
2.1.8 Palm kernel oil is derived from the kernel of the fruit of the oil palm (Elaeis guineensis).
2.1.9 Palm oil is derived from the fleshy mesocarp of the fruit of the oil palm (Elaeis guineensis).
2.1.10 Palm olein is the liquid fraction derived from the fractionation of palm oil (described above).
2.1.11 Palm stearin is the high-melting fraction derived from the fractionation of palm oil (described above).
2.1.12 Rapeseed oil (turnip rape oil; colza oil; ravison oil; sarson oil: toria oil) is produced from seeds of Brassica napus L., Brassica campestris L., Brassica juncea L. and Brassica tournefortii Gouan species.
2.1.13 Rapeseed oil - low erucic acid (low erucic acid turnip rape oil; low erucic acid colza oil; canola oil) is produced from low erucic acid oil-bearing seeds of varieties derived from the Brassica napus L., Brassica campestris L. and Brassica juncea L., species.
2.1.14 Safflowerseed oil (safflower oil; carthamus oil; kurdee oil) is derived from safflower seeds (seeds of Carthamus tinctorius L.).
2.1.15 Safflowerseed oil - high oleic acid (high oleic acid safflower oil; high oleic acid carthamus oil; high oleic acid kurdee oil) is produced from high oleic acid oil-bearing seeds of varieties derived from Carthamus tinctorius L.
2.1.16 Sesameseed oil (sesame oil; gingelly oil; benne oil; ben oil; till oil; tillie oil) is derived from sesame seeds (seeds of Sesamum indicum L.).
2.1.17 Soya bean oil (soybean oil) is derived from soya beans (seeds of Glycine max (L.) Merr.).
2.1.18 Sunflowerseed oil (sunflower oil) is derived from sunflower seeds (seeds of Helianthus annuus L.).
2.1.19 Sunflowerseed oil - high oleic acid (high oleic acid sunflower oil) is produced from high oleic acid oil-bearing seeds of varieties derived from sunflower seeds (seeds of Helianthus annuus L.).
2.2 Other Definitions
2.2.1 Edible vegetable oils are foodstuffs which are composed primarily of glycerides of fatty acids being obtained only from vegetable sources. They may contain small amounts of other lipids such as phosphatides, of unsaponifiable constituents and of free fatty acids naturally present in the fat or oil.
2.2.2 Virgin oils are obtained, without altering the nature of the oil, by mechanical procedures, e.g. expelling or pressing, and the application of heat only. They may have been purified by washing with water, settling, filtering and centrifuging only.
2.2.3 Cold pressed oils are obtained, without altering the oil, by mechanical procedures only, e.g. expelling or pressing, without the application of heat. They may have been purified by washing with water, settling, filtering and centrifuging only.
3. ESSENTIAL COMPOSITION AND QUALITY FACTORS
3.1 GLC Ranges of Fatty Acid Composition (expressed as percentages)
Samples falling within the appropriate ranges specified in Table 1 are in compliance with this Standard. Supplementary criteria, for example national geographical and/or climatic variations, may be considered, as necessary, to confirm that a sample is in compliance with the Standard.
3.1.1 Low-erucic acid rapeseed oil must not contain more than 2% erucic acid (as % of total fatty acids).
3.1.2 High oleic acid safflower oil must contain not less than 70% oleic acid (as a % of total fatty acids).
3.1.3 High oleic acid sunflower oil must contain not less than 75% oleic acid (as % of total fatty acids).
3.3 Slip Point
|
Palm olein |
not more than 24°C |
|
Palm stearin |
not less than 44°C |
4.1 No food additives are permitted in virgin or cold pressed oils.
4.2 Flavours
Natural flavours and their identical synthetic equivalents, and other synthetic flavours, except those which are known to represent a toxic hazard.
4.3 Antioxidants
|
|
|
|
Maximum Level |
|
304 |
Ascorbyl palmitate |
) |
500 mg/kg |
|
305 |
Ascorbyl stearate |
) |
individually or in combination |
|
306 |
Mixed tocopherols concentrate |
|
GMP |
|
307 |
Alpha-tocopherol |
|
GMP |
|
308 |
Synthetic gamma-tocopherol |
|
GMP |
|
309 |
Synthetic delta-tocopherol |
|
GMP |
|
310 |
Propyl gallate |
|
100 mg/kg |
|
319 |
Tertiary butyl hydroquinone (TBHQ) |
|
120 mg/kg |
|
320 |
Butylated hydroxyanisole (BHA) |
|
175 mg/kg |
|
321 |
Butylated hydroxytoluene (BHT) |
|
75 mg/kg |
|
|
Any combination of gallates, BHA and BHT and/or TBHQ
|
|
200 mg/kg but limits above not to be exceeded |
|
389 |
Dilauryl thiodipropionate |
|
200 mg/kg |
|
|
|
|
Maximum Level |
|
330 |
Citric acid |
|
GMP |
|
331 |
Sodium citrates |
|
GMP |
|
384 |
Isopropyl citrates |
) |
100 mg/kg individually or in combination |
|
|
Monoglyceride citrate |
) |
|
|
|
Maximum Level |
|
900a |
Polydimethylsiloxane |
10 mg/kg |
5.1 Heavy Metals
The products covered by the provisions of this Standard shall comply with maximum limits being established by the Codex Alimentarius Commission but in the meantime the following limits will apply:
|
|
Maximum permissible concentration |
|
Lead (Pb) |
0.1 mg/kg |
|
Arsenic (As) |
0.1 mg/kg |
The products covered by the provisions of this Standard shall comply with those maximum residue limits established by the Codex Alimentarius Commission for these commodities.
6. HYGIENE
6.1 It is recommended that the products covered by the provisions of this Standard be prepared and handled in accordance with the appropriate sections of the Recommended International Code of Practice - General Principles of Food Hygiene (CAC/RCP 1-1969, Rev. 3-1997), and other relevant Codex texts such as Codes of Hygienic Practice and Codes of Practice.
6.2 The products should comply with any microbiological criteria established in accordance with the Principles for the Establishment and Application of Microbiological Criteria for Foods (CAC/GL 21-1997).
7. LABELLING
7.1 Name of the Food
The product shall be labelled in accordance with the Codex General Standard for the Labelling of Prepackaged Foods (CODEX STAN 1-1985, Rev. 1-1991). The name of the oil shall conform to the descriptions given in Section 2 of this Standard.
Where more than one name is given for a product in Section 2.1, the labelling of that product must include one of those names acceptable in the country of use.
7.2 Labelling of Non-retail Containers
Information on the above labelling requirements shall be given either on the container or in accompanying documents, except that the name of the food, lot identification and the name and address of the manufacturer or packer shall appear on the container.
However, lot identification and the name and address of the manufacturer or packer may be replaced by an identification mark, provided that such a mark is clearly identifiable with the accompanying documents.
8. METHODS OF ANALYSIS AND SAMPLING
8.1 Determination of GLC Ranges of Fatty Acid Composition
According to IUPAC 2.301, 2.302 and 2.304 or ISO 5508: 1990 and 5509: 2000 or AOCS Ce 2-66, Ce 1e-91 or Ce 1f-96.
8.2 Determination of Slip Point
According to ISO 6321: 1991 and Amendment 1: 1998 for all oils, or AOCS Cc 3b-92 or Ce 3-25 (97) for palm oils only.
8.3 Determination of Arsenic
According to AOAC 952.13, IUPAC 3.136, AOAC 942.17, or AOAC 985.16.
8.4 Determination of Lead
According to IUPAC 2.632, AOAC 994.02 or ISO 12193: 1994 or AOCS Ca 18c-91.
Table 1: Fatty acid composition of vegetable oils as determined by gas liquid chromatography from authentic samples[2] (expressed as percentage of total fatty acids) (see Section 3.1 of the Standard)
|
Fatty acid |
Arachis oil |
Babassu oil |
Coconut oil |
Cottonseed oil |
Grapeseed oil |
Maize oil |
Mustardseed oil |
Palm oil |
Palm kernel oil |
Palm olein |
|
C6:0 |
ND |
ND |
ND-0.7 |
ND |
ND |
ND |
ND |
ND |
ND-0.8 |
ND |
|
C8:0 |
ND |
2.6-7.3 |
4.6-10.0 |
ND |
ND |
ND |
ND |
ND |
2.4-6.2 |
ND |
|
C10:0 |
ND |
1.2-7.6 |
5.0-8.0 |
ND |
ND |
ND |
ND |
ND |
2.6-5.0 |
ND |
|
C12:0 |
ND-0.1 |
40.0-55.0 |
45.1 53.2 |
ND-0.2 |
ND |
ND-0.3 |
ND |
ND-0.5 |
45.0-55.0 |
0.1-0.5 |
|
C14:0 |
ND-0.1 |
11.0-27.0 |
16.8-21.0 |
0.6-1.0 |
ND-0.3 |
ND-0.3 |
ND-1.0 |
0.5-2.0 |
14.0-18.0 |
0.5-1.5 |
|
C16:0 |
8.0-14.0 |
5.2-11.0 |
7.5-10.2 |
21.4-26.4 |
5.5-11.0 |
8.6-16.5 |
0.5-4.5 |
39.3-47.5 |
6.5-10.0 |
38.0-43.5 |
|
C16:1 |
ND-0.2 |
ND |
ND |
ND-1.2 |
ND-1.2 |
ND-0.5 |
ND-0.5 |
ND-0.6 |
ND-0.2 |
ND-0.6 |
|
C17:0 |
ND-0.1 |
ND |
ND |
ND-0.1 |
ND-0.2 |
ND-0.1 |
ND |
ND-0.2 |
ND |
ND-0.2 |
|
C17:1 |
ND-0.1 |
ND |
ND |
ND-0.1 |
ND-0.1 |
ND-0.1 |
ND |
ND |
ND |
ND-0.1 |
|
C18:0 |
1.0-4.5 |
1.8-7.4 |
2.0-4.0 |
2.1-3.3 |
3.0-6.5 |
ND-3.3 |
0.5-2.0 |
3.5-6.0 |
1.0-3.0 |
3.5-.5.0 |
|
C18:1 |
35.0-69 |
9.0-20.0 |
5.0-10.0 |
14.7-21.7 |
12.0-28.0 |
20.0-42.2 |
8.0-23.0 |
36.0-44.0 |
12.0-19.0 |
39.8-46.0 |
|
C18:2 |
12.0-43.0 |
1.4-6.6 |
1.0-2.5 |
46.7-58.2 |
58.0-78.0 |
34.0-65.6 |
10.0-24.0 |
9.0-12.0 |
1.0-3.5 |
10.0-13.5 |
|
C18:3 |
ND-0.3 |
ND |
ND-0.2 |
ND-0.4 |
ND-1.0 |
ND-2.0 |
6.0-18.0 |
ND-0.5 |
ND-0.2 |
ND-0.6 |
|
C20:0 |
1.0-2.0 |
ND |
ND-0.2 |
0.2-0.5 |
ND-1.0 |
0.3-1.0 |
ND-1.5 |
ND-1.0 |
ND-0.2 |
ND-0.6 |
|
C20:1 |
0.7-1.7 |
ND |
ND-0.2 |
ND-0.1 |
ND-0.3 |
0.2-0.6 |
5.0-13.0 |
ND-0.4 |
ND-0.2 |
ND-0.4 |
|
C20:2 |
ND |
ND |
ND |
ND-0.1 |
ND |
ND-0.1 |
ND-1.0 |
ND |
ND |
ND |
|
C22:0 |
1.5-4.5 |
ND |
ND |
ND-0.6 |
ND-0.5 |
ND-0.5 |
0.2-2.5 |
ND-0.2 |
ND-0.2 |
ND-0.2 |
|
C22:1 |
ND-0.3 |
ND |
ND |
ND-0.3 |
ND-0.3 |
ND-0.3 |
22.0-50.0 |
ND |
ND |
ND |
|
C22:2 |
ND |
ND |
ND |
ND-0.1 |
ND |
ND |
ND-1.0 |
ND |
ND |
ND |
|
C24:0 |
0.5-2.5 |
ND |
ND |
ND-0.1 |
ND-0.4 |
ND-0.5 |
ND-0.5 |
ND |
ND |
ND |
|
C24:1 |
ND-0.3 |
ND |
ND |
ND |
ND |
ND |
0.5-2.5 |
ND |
ND |
ND |
|
Fatty acid |
Palm stearin |
Rapeseed oil |
Rapeseed oil (low erucic acid) |
Safflowerseed oil |
Safflowerseed oil (high oleic acid) |
Sesameseed oil |
Soyabean oil |
Sunflowerseed oil |
Sunflowerseed oil (high oleic acid) |
|
C6:0 |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
|
C8:0 |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
|
C10:0 |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
|
C12:0 |
0.1-0.5 |
ND |
ND |
ND |
ND-0.2 |
ND |
ND-0.1 |
ND-0.1 |
ND |
|
C14:0 |
1.0-2.0 |
ND-0.2 |
ND-0.2 |
ND-0.2 |
ND-0.2 |
ND-0.1 |
ND-0.2 |
ND-0.2 |
ND-0.1 |
|
C16:0 |
48.0-74.0 |
1.5-6.0 |
2.5-7.0 |
5.3-8.0 |
3.6-6.0 |
7.9-12.0 |
8.0-13.5 |
5.0-7.6 |
2.6-5.0 |
|
C16:1 |
ND-0.2 |
ND-3.0 |
ND-0.6 |
ND-0.2 |
ND-0.2 |
0.1-0.2 |
ND-0.2 |
ND-0.3 |
ND-0.1 |
|
C17:0 |
ND-0.2 |
ND-0.1 |
ND-0.3 |
ND-0.1 |
ND-0.1 |
ND-0.2 |
ND-0.1 |
ND-0.2 |
ND-0.1 |
|
C17:1 |
ND-0.1 |
ND-0.1 |
ND-0.3 |
ND-0.1 |
ND-0.1 |
ND-0.1 |
ND-0.1 |
ND-0.1 |
ND-0.1 |
|
C18:0 |
3.9-6.0 |
0.5-3.1 |
0.8-3.0 |
1.9-2.9 |
1.5-2.4 |
4.8-6.1 |
2.0-5.4 |
2.7-6.5 |
2.9-6.2 |
|
C18:1 |
15.5-36.0 |
8.0-60.0 |
51.0-70.0 |
8.4-21.3 |
70.0-83.7 |
35.9-42.3 |
17-30 |
14.0-39.4 |
75-90.7 |
|
C18:2 |
3.0-10.0 |
11.0-23.0 |
15.0-30.0 |
67.8-83.2 |
9.0-19.9 |
41.5-47.9 |
48.0-59.0 |
48.3-74.0 |
2.1-17 |
|
C18:3 |
ND-0.5 |
5.0-13.0 |
5.0-14.0 |
ND-0.1 |
ND-1.2 |
0.3-0.4 |
4.5-11.0 |
ND-0.3 |
ND-0.3 |
|
C20:0 |
ND-1.0 |
ND-3.0 |
0.2-1.2 |
0.2-0.4 |
0.3-0.6 |
0.3-0.6 |
0.1-0.6 |
0.1-0.5 |
0.2-0.5 |
|
C20:1 |
ND-0.4 |
3.0-15.0 |
0.1-4.3 |
0.1-0.3 |
0.1-0.5 |
ND-0.3 |
ND-0.5 |
ND-0.3 |
0.1-0.5 |
|
C20:2 |
ND |
ND-1.0 |
ND-0.1 |
ND |
ND |
ND |
ND-0.1 |
ND |
ND |
|
C22:0 |
ND-0.2 |
ND-2.0 |
ND-0.6 |
ND-1.0 |
ND-0.4 |
ND-0.3 |
ND-0.7 |
0.3-1.5 |
0.5-1.6 |
|
C22:1 |
ND |
> 2.0-60.0 |
ND-2.0 |
ND-1.8 |
ND-0.3 |
ND |
ND-0.3 |
ND-0.3 |
ND-0.3 |
|
C22:2 |
ND |
ND-2.0 |
ND-0.1 |
ND |
ND |
ND |
ND |
ND-0.3 |
ND |
|
C24: 0 |
ND |
ND-2.0 |
ND-0.3 |
ND-0.2 |
ND-0.3 |
ND-0.3 |
ND-0.5 |
ND-0.5 |
ND-0.5 |
|
C24:1 |
ND |
ND-3.0 |
ND-0.4 |
ND-0.2 |
ND-0.3 |
ND |
ND |
ND |
ND |
ND - non detectable, defined as £ 0.05%.
APPENDIX. OTHER QUALITY AND COMPOSITION FACTORS
This text is intended for voluntary application by commercial partners and not for application by governments.
1. QUALITY CHARACTERISTICS
1.1 The colour, odour and taste of each product shall be characteristic of the designated product. It shall be free from foreign and rancid odour and taste.
|
|
Maximum level |
|
1.2 Matter Volatile at 105°C |
0.2 % m/m |
|
1.3 Insoluble Impurities |
0.05 % m/m |
|
1.4 Soap Content |
0.005 % m/m |
|
1.5 Iron (Fe): |
|
|
Refined oils |
1.5 mg/kg |
|
Virgin oils |
5.0 mg/kg |
|
1.6 Copper (Cu) |
|
|
Refined oils |
0.1 mg/kg |
|
Virgin oils |
0.4 mg/kg |
|
1.7 Acid Value |
|
|
Refined oils |
0.6 mg KOH/g Oil |
|
Cold pressed and virgin oils |
4.0 mg KOH/g Oil |
|
Virgin palm oils |
10.0 mg KOH/g Oil |
|
1.8 Peroxide Value: |
|
|
Refined oils |
up to 10 milliequivalents of active oxygen/kg oil |
|
Cold pressed and virgin oils |
up to 15 milliequivalents of active oxygen/kg oil |
2.1 The arachidic and higher fatty acid content of arachis oil should not exceed 48g/kg.
2.2 The Reichert values for coconut, palm kernel and babassu oils should be in the ranges 6-8.5, 4-7 and 4.5-6.5, respectively.
2.3 The Polenske values for coconut, palm kernel and babassu oils should be in the ranges 13-18, 8-12 and 8-10, respectively.
2.4 The Halphen test for cottonseed oil should be positive.
2.5 The erythrodiol content of grapeseed oil should be more than 2% of the total sterols.
2.6 The total carotenoids (as beta-carotene) for unbleached palm oil, unbleached palm olein and unbleached palm stearin should be in the range 500-2000, 550-2500 and 300-1500 mg/kg, respectively.
2.7 The Crismer value for low erucic acid rapeseed oil should be in the range 67-70.
2.8 The concentration of brassicasterol in low erucic acid rapeseed oil should be greater than 5% of total sterols.
2.9 The Baudouin test should be positive for sesameseed oil.
3. CHEMICAL AND PHYSICAL CHARACTERISTICS
Chemical and Physical Characteristics are given in Table 2.
4. IDENTITY CHARACTERISTICS
4.1 Levels of desmethylsterols in vegetable oils as a percentage of total sterols are given in Table 3.
4.2 Levels of tocopherols and tocotrienols in vegetable oils are given in Table 4.
5. METHODS OF ANALYSIS AND SAMPLING
5.1 Determination of Matter Volatile at 105°C
According to IUPAC 2.601 or ISO 662: 1998.
5.2 Determination of Insoluble Impurities
According to IUPAC 2.604 or ISO 663: 2000.
5.3 Determination of Soap Content
According to BS 684 Section 2.5.
5.4 Determination of Copper and Iron
According to ISO 8294: 1994, IUPAC 2.631 or AOAC 990.05 or AOCS Ca 18b-91.
5.5 Determination of Relative Density
According to IUPAC 2.101, with the appropriate conversion factor.
5.6 Determination of Apparent Density
According to ISO 6883: 2000 with the appropriate conversion factor or AOCS Cc 10c-95.
5.7 Determination of Refractive Index
According to IUPAC 2.102 or ISO 6320: 2000 or AOCS Ce 7-25.
5.8 Determination of Saponification Value (SV)
According to IUPAC 2.202 or ISO 3657: 1988.
5.9 Determination of Iodine Value (IV)
Wijs - according to IUPAC 2.205/1, ISO 3961: 1996, AOAC 993.20, or AOCS Cd 1d-92 (97), or by calculation - AOCS Cd 1b-87 (97). The method to be used for specific named vegetable oils is stipulated in the Standard.
5.10 Determination of Unsaponifiable Matter
According to IUPAC 2.401 (part 1-5) or ISO 3596: 2000 or ISO 18609: 2000.
5.11 Determination of Peroxide Value (PV)
According to IUPAC 2.501 (as amended), AOCS Cd 8b - 90 (97) or ISO 3961: 1998.
5.12 Determination of Total Carotenoids
According to BS 684 Section 2.20.
5.13 Determination of Acidity
According to IUPAC 2.201 or ISO 660: 1996 or AOCS Cd 3d-63.
5.14 Determination of Sterol Content
According to ISO 12228:1999, or IUPAC 2.403.
5.15 Determination of Tocopherol Content
According to IUPAC 2.432 or ISO 9936: 1997 or AOCS Ce 8-89.
5.16 Halphen Test
According to AOCS Cb 1-25 (97).
5.17 Crismer Value
According to AOCS Cb 4-35 (97) and AOCS Ca 5a-40 (97).
5.18 Baudouin Test (modified Villavecchia test or sesameseed oil test)
According to AOCS Cb 2-40 (97).
5.19 Reichert Value and Polenske Value
According to IUPAC 2.204.
Table 2: Chemical and physical characteristics of crude vegetable oils (see Appendix of the Standard)
|
|
Arachis oil |
Babassu oil |
Coconut oil |
Cottonseed oil |
Grapeseed oil |
Maize oil |
Mustardseed oil |
Palm oil |
Palm kernel |
|
Relative density (xºC/water at
20ºC) |
0.912-0.920 |
0.914-0.917 |
0.908-0.921 |
0.918-0.926 |
0.920-0.926 |
0.917-0.925 |
0.910-0.921 |
0.891-0.899 |
0.899-0.914 |
|
Apparent density (g/ml) |
|
|
|
|
|
|
|
0.889-0.895 (50ºC) |
|
|
Refractive index (ND 40ºC) |
1.460-1.465 |
1.448-1.451 |
1.448-1.450 |
1.458-1.466 |
1.467-1.477 |
1.465-1.468 |
1.461-1.469 |
1.454-1.456 at 50ºC |
1.448-1.452 |
|
Saponification value (mg KOH/g oil) |
187-196 |
245-256 |
248-265 |
189-198 |
188-194 |
187-195 |
168-184 |
190-209 |
230-254 |
|
Iodine value |
86-107 |
10-18 |
6.3-10.6 |
100-123 |
128-150 |
103-135 |
92-125 |
50.0-55.0 |
14.1-21.0 |
|
Unsaponifiable matter (g/kg) |
£ 10 |
£ 12 |
£ 15 |
£ 15 |
£ 20 |
£ 28 |
£ 15 |
£ 12 |
£ 10 |
|
Stable carbon isotope ratio * |
|
|
|
|
|
-13.71 to-16.36 |
|
|
|
|
|
Palm olein |
Palm stearin |
Rapeseed oil |
Rapeseed oil (low erucic acid) |
Safflowerseed oil |
Safflowerseed oil (high oleic acid) |
Sesameseed oil |
Soyabean oil |
Sunflowerseed oil |
Sunflowerseed oil (high oleic acid) |
|
Relative density (xº C/water at 20ºC)
|
0.899-0.920 |
0.881-0.891 |
0.910-0.920 |
0.914-0.920 |
0.922-0.927 |
0.913-0.919 |
0.915-0.924 |
0.919-0.925 |
0.918-0.923 |
0.909-0.915=25oC |
|
Apparent density (g/ml) |
0896-0.898 at 40ºC |
0.881-0.885 at 60ºC |
|
|
|
0.912-0.914 at 20°C |
|
|
|
|
|
Refractive index (ND 40ºC) |
1.458-1.460 |
1.447-1.452 at 60ºC |
1.465-1.469 |
1.465-1.467 |
1.467-1.470 |
1.460-1.464 at 40oC; 1.466-1.470 at 25oC
|
1.465-1.469 |
1.466-1.470 |
1.461-1.468 |
1.467-1.471 at 25oC |
|
Saponification value (mg KOH/g oil) |
194-202 |
193-205 |
168-181 |
182-193 |
186-198 |
186-194 |
186-195 |
189-195 |
188-194 |
182-194 |
|
Iodine value |
³ 56 |
£ 48 |
94-120 |
105-126 |
136-148 |
80-100 |
104-120 |
124-139 |
118-141 |
78-90 |
|
Unsaponifiable matter (g/kg) |
£ 13 |
£ 9 |
£ 20 |
£ 20 |
£ 15 |
£ 10 |
£ 20 |
£ 15 |
£ 15 |
£ 15 |
* See the following publications:Table 3: Levels of desmethylsterols in crude vegetable oils from authentic samples[3] as a percentage of total sterols (see Appendix 1 of the Standard)Woodbury SP, Evershed RP and Rossell JB (1998). Purity assessments of major vegetable oils based on gamma 13C values of individual fatty acids. JAOCS, 75 (3), 371-379.
Woodbury SP, Evershed RP and Rossell JB (1998). Gamma 13C analysis of vegetable oil, fatty acid components, determined by gas chromatography-combustion-isotope ratio mass spectrometry, after saponification or regiospecific hydrolysis. Journal of Chromatography A, 805, 249-257.
Woodbury SP, Evershed RP, Rossell JB, Griffith R and Farnell P (1995). Detection of vegetable oil adulteration using gas chromatography combustion / isotope ratio mass spectrometry. Analytical Chemistry 67 (15), 2685-2690.
Ministry of Agriculture, Fisheries and Food (1996). Authenticity of single seed vegetable oils. Working Party on Food Authenticity, MAFF, UK.
|
|
Arachis oil |
Babassu oil |
Coconut oil |
Cottonseed oil |
Grapeseed oil |
Maize oil |
Palm oil |
Palm kernel oil |
|
Cholesterol |
ND-3.8 |
1.2-1.7 |
ND-3.0 |
0.7-2.3 |
ND-0.5 |
0.2-0.6 |
2.6-6.7 |
0.6-3.7 |
|
Brassicasterol |
ND-0.2 |
ND-0.3 |
ND-0.3 |
0.1-0.3 |
ND-0.2 |
ND-0.2 |
ND |
ND-0.8 |
|
Campesterol |
12.0-19.8 |
17.7-18.7 |
6.0-11.2 |
6.4-14.5 |
7.5-14.0 |
16.0-24.1 |
18.7-27.5 |
8.4-12.7 |
|
Stigmasterol |
5.4-13.2 |
8.7-9.2 |
11.4-15.6 |
2.1-6.8 |
7.5-12.0 |
4.3-8.0 |
8.5-13.9 |
12.0-16.6 |
|
Beta-sitosterol |
47.4-69.0 |
48.2-53.9 |
32.6-50.7 |
76.0-87.1 |
64.0-70.0 |
54.8-66.6 |
50.2-62.1 |
62.6-73.1 |
|
Delta-5-avenasterol |
5.0-18.8 |
16.9-20.4 |
20.0-40.7 |
1.8-7.3 |
1.0-3.5 |
1.5-8.2 |
ND-2.8 |
1.4-9.0 |
|
Delta-7-stigmastenol |
ND-5.1 |
ND |
ND-3.0 |
ND-1.4 |
0.5-3.5 |
0.2-4.2 |
0.2-2.4 |
ND-2.1 |
|
Delta-7-avenasterol |
ND-5.5 |
0.4-1.0 |
ND-3.0 |
0.8-3.3 |
0.5-1.5 |
0.3-2.7 |
ND-5.1 |
ND-1.4 |
|
Others |
ND-1.4 |
ND |
ND-3.6 |
ND-1.5 |
ND-5.1 |
ND-2.4 |
ND |
ND-2.7 |
|
Total sterols (mg/kg) |
900-2900 |
500-800 |
400-1200 |
2700-6400 |
2000-70*00 |
7000-22100 |
300-700 |
700-1400 |
|
|
Rapeseed oil (low erucic acid) |
Safflowerseed oil |
Safflowerseed oil (high oleic acid) |
Sesameseed oil |
Soyabean oil |
Sunflowerseed oil |
Sunflowerseed oil (high oleic acid) |
|
Cholesterol |
ND-1.3 |
ND-0.7 |
ND-0.5 |
0.1-0.5 |
0.2-1.4 |
ND-0.7 |
ND-0.5 |
|
Brassicasterol |
5.0-13.0 |
ND-0.4 |
ND-2.2 |
0.1-0.2 |
ND-0.3 |
ND-0.2 |
ND-0.3 |
|
Campesterol |
24.7-38.6 |
9.2-13.3 |
8.9-19.9 |
10.1-20.0 |
15.8-24.2 |
6.5-13.0 |
5.0-13.0 |
|
Stigmasterol |
0.2-1.0 |
4.5-9.6 |
2.9-8.9 |
3.4-12.0 |
14.9-19.1 |
6.0-13.0 |
4.5-13.0 |
|
Beta-sitosterol |
45.1-57.9 |
40.2-50.6 |
40.1-66.9 |
57.7-61.9 |
47.0-60 |
50-70 |
42.0-70 |
|
Delta-5-avenasterol |
2.5-6.6 |
0.8-4.8 |
0.2-8.9 |
6.2-7.8 |
1.5-3.7 |
ND-6.9 |
1.5-6.9 |
|
Delta-7-stigmastenol |
ND-1.3 |
13.7-24.6 |
3.4-16.4 |
0.5-7.6 |
1.4-5.2 |
6.5-24.0 |
6.5-24.0 |
|
Delta-7-avenasterol |
ND-0.8 |
2.2-6.3 |
ND-8.3 |
1.2-5.6 |
1.0-4.6 |
3.0-7.5 |
ND-9.0 |
|
Others |
ND-4.2 |
0.5-6.4 |
4.4-11.9 |
0.7-9.2 |
ND-1.8 |
ND-5.3 |
3.5-9.5 |
|
Total sterols (mg/kg) |
4500-11300 |
2100-4600 |
2000-4100 |
4500-19000 |
1800-4500 |
2400-5000 |
1700-5200 |
ND - Non-detectable, defined as £ 0.05%Table 4: Levels of tocopherols and tocotrienols in crude vegetable oils from authentic samples[4] (mg/kg) (see Appendix 1 of the Standard)
|
|
Arachis oil |
Babassu oil |
Coconut oil |
Cottonseed oil |
Grapeseed oil |
Maize oil |
Palm oil |
Palm kernel oil |
|
Alpha-tocopherol |
49-373 |
ND |
ND-17 |
136-674 |
16-38 |
23-573 |
4-193 |
ND-44 |
|
Beta-tocopherol |
ND-41 |
ND |
ND-11 |
ND-29 |
ND-89 |
ND-356 |
ND-234 |
ND-248 |
|
Gamma-tocopherol |
88-389 |
ND |
ND-14 |
138-746 |
ND-73 |
268-2468 |
ND-526 |
ND-257 |
|
Delta-tocopherol |
ND-22 |
ND |
ND |
ND-21 |
ND-4 |
23-75 |
ND-123 |
ND |
|
Alpha-tocotrienol |
ND |
25-46 |
ND-44 |
ND |
18-107 |
ND-239 |
4-336 |
ND |
|
Gamma-tocotrienol |
ND |
32-80 |
ND-1 |
ND |
115-205 |
ND-450 |
14-710 |
ND-60 |
|
Delta-tocotrienol |
ND |
9-10 |
ND |
ND |
ND-3.2 |
ND-20 |
ND-377 |
ND |
|
Total (mg/kg) |
170-1300 |
60-130 |
ND-50 |
380-1200 |
240-410 |
330-3720 |
150-1500 |
ND-260 |
|
|
Rapeseed oil (low erucic acid) |
Safflowerseed oil |
Safflowerseed oil (high oleic acid) |
Sesameseed oil |
Soyabean oil |
Sunflowerseed oil |
Sunflowerseed oil (high oleic acid) |
|
Alpha-tocopherol |
100-386 |
234-660 |
234-660 |
ND-3.3 |
9-352 |
403-935 |
400-1090 |
|
Beta-tocopherol |
ND-140 |
ND-17 |
ND-13 |
ND |
ND-36 |
ND-45 |
10-35 |
|
Gamma-tocopherol |
189-753 |
ND-12 |
ND-44 |
521-983 |
89-2307 |
ND-34 |
3-30 |
|
Delta-tocopherol |
ND-22 |
ND |
ND-6 |
4-21 |
154-932 |
ND-7.0 |
ND-17 |
|
Alpha-tocotrienol |
ND |
ND |
ND |
ND |
ND-69 |
ND |
ND |
|
Gamma-tocotrienol |
ND |
ND-12 |
ND-10 |
ND-20 |
ND-103 |
ND |
ND |
|
Delta-tocotrienol |
ND |
ND |
ND |
ND |
ND |
ND |
ND |
|
Total (mg/kg) |
430-2680 |
240-670 |
250-700 |
330-1010 |
600-3370 |
440-1520 |
450-1120 |
ND - Non-detectable.
Note: Maize oil also contains ND-52 mg/kg beta tocotrienol.
1. SCOPE
This Standard applies to virgin olive oil, refined olive oil, refined olive-pomace oil, blends of refined olive oil and virgin olive oil and blends of refined olive-pomace oil and virgin olive oil.
2. DESCRIPTION
2.1 Olive oil is the oil obtained from the fruit of the olive tree (0lea europaea sativa Hoffm. et Link) without having been subjected to manipulation or any treatment not authorized by sub-sections 2.2 and 2.3 of this Standard.
2.2 Virgin olive oil is the oil obtained from the fruit of the olive tree by mechanical or other physical means under conditions, particularly thermal, which do not lead to alteration of the oil. Virgin olive oil is an oil which is suitable for consumption in the natural state.
2.3 Refined olive oil is the oil obtained from virgin olive oil, the acid content and/or organoleptic characteristics of which render it unsuitable for consumption in the natural state, by means of refining methods which do not lead to alterations in the initial glyceridic structure.
2.4 Refined olive-pomace oil is the oil obtained from “olive pomace” by extraction by means of solvents and made edible by means of refining methods which do not lead to alteration in the initial glyceridic structure.
3. ESSENTIAL COMPOSITION AND QUALITY FACTORS[6]
3.1 Identity Characteristics (under normal ecological conditions)[7]
3.1.1 GLC ranges of fatty acid composition (% m/m of methyl esters)
|
Lauric acid |
(C 12:0) |
Not present in discernible amounts |
|
Myristic acid |
(C 14:0) |
< 0.1 |
|
Palmitic acid |
(C 16:0) |
7.5 - 20.0 |
|
Palmitoleic acid |
(C 16:1) |
0.3 - 3.5 |
|
Heptadecanoic acid |
(C 17:0) |
< 0.5 |
|
Heptadecenoic acid |
(C 17:1) |
< 0.6 |
|
Stearic acid |
(C 18:0) |
0.5 - 5.0 |
|
Oleic acid |
(C 18:1) |
55.0 - 83.0 |
|
Linoleic acid |
(C 18:2) |
3.5 - 21.0 |
|
Linolenic acid |
(C 18:3) |
< 1.5 |
|
Arachidic acid |
(C 20:0) |
< 0.8 |
|
Behenic acid |
(C 22:0) |
< 0.3 |
|
Erucic acid |
(C 22:1) |
Not present in discernible amounts |
|
Lignoceric acid |
(C 24:0) |
< 1.0 |
3.1.2.1 Relative density (20oC/water at 20oC)
|
Virgin olive oil |
) |
0.910 - 0.916 |
|
Refined olive oil |
) |
|
|
Refined olive-pomace oil |
) |
|
Virgin olive oil |
) |
1.4677 - 1.4705 |
|
Refined olive oil |
) |
|
|
Refined olive-pomace oil |
|
1.4680 - 1.4707 |
|
Virgin olive oil |
) |
184 - 196 |
|
Refined olive oil |
) |
|
|
Refined olive-pomace oil |
|
182 - 193 |
|
Virgin olive oil |
) |
75 - 94 |
|
Refined olive oil |
) |
|
|
Refined olive-pomace oil |
|
75 - 92 |
|
Virgin olive oil |
) |
not more than 15 g/kg[8] |
|
Refined olive oil |
) |
|
|
Refined olive-pomace oil |
|
not more than 30 g/kg[9] |
|
Virgin olive oil |
not more than 17[10] |
|
Refined olive oil |
|
|
Refined olive-pomace oil |
not applicable |
|
Virgin olive oil |
) |
negative |
|
Refined olive oil |
) |
|
|
Refined olive-pomace oil |
) |
|
Virgin olive oil |
) |
negative |
|
Refined olive oil |
) |
|
|
Refined olive-pomace oil |
|
not relevant |
|
Virgin olive oil |
) |
negative |
|
Refined olive oil |
) |
|
|
Refined olive-pomace oil |
) |
|
Virgin olive oil |
) |
negative |
|
Refined olive oil |
) |
|
|
Refined olive-pomace oil |
) |
|
Virgin olive oil |
) |
negative |
|
Refined olive oil |
) |
|
|
Refined olive-pomace oil |
) |
|
|
|
Beta-sitosterol |
Campesterol |
Cholesterol |
|
Virgin olive oil |
) |
³93 |
£ 4.0 |
£ 0.5 |
|
Refined olive oil |
) |
|||
|
Refined olive-pomace oil |
) |
|
|
Maximum level |
|
Virgin olive oil |
1.5% m/m |
|
Refined olive oil |
1.8% m/m |
|
Blends of refined olive oil and virgin olive oil |
1.8% m/m |
|
Refined olive-pomace oil |
2.2% m/m |
|
Blends of refined olive-pomace oil and virgin olive
oil |
2.0% m/m |
3.2 Quality Characteristics
3.2.1 Colour, odour and taste
Virgin olive oil: Clear oil, of a yellow to green colour, with specific odour and taste, free from odours or tastes indicating alteration or pollution of oil.
Refined olive oil: Clear oil, limpid without sediment, of clear yellow colour without specific odour or taste and free from odours or tastes indicating alteration or pollution of the oil.
Refined olive-pomace oil: Clear oil, limpid, without sediment, of a yellow to yellow-brown colour, without specific odour or taste and free from odours or tastes indicating alteration or pollution of the oil.
Blends: The colour, odour and taste shall be intermediate between those of two types blended.
3.2.2 Free acidity
|
|
Acidity maximum % |
Acid value maximum |
|
Virgin olive oil |
3.3 |
6.6 |
|
Refined olive oil |
0.3 |
0.6 |
|
Refined olive-pomace oil |
0.3 |
0.6 |
|
Blends |
l.5 |
3.0 |
|
Virgin olive oil |
£ 20 |
|
Refined olive oil |
£ 10 |
|
Refined olive-pomace oil |
£10 |
|
Blends |
£ 20 |
|
|
Extinction (E) |
Extinction (E) |
D E |
|
Virgin olive oil |
3.50 |
0.30 |
|
|
Refined olive oil |
- |
1.10 |
0.16 |
|
Refined olive-pomace oil |
6.00 |
2.00 |
0.20 |
|
Blends of refined olive oil and virgin olive oil |
- |
0.90 |
0.15 |
|
Blends of refined olive-pomace oil and virgin olive
oil |
5.50 |
1.70 |
0.18 |
|
|
Maximum level |
|||
|
4.1 |
Virgin olive oil |
|
None permitted |
|
|
4.2 |
Refined olive oil |
) |
Alpha-tocopherol for the purpose of restoring natural tocopherol lost
in processing |
200 mg/kg total alpha-tocopherol in the final product |
|
|
Refined olive-pomace oil |
) |
||
|
|
Blends |
) |
||
|
5.1 |
Matter volatile at 105oC |
|
|
|
|
Virgin olive oil |
|
£ 0.2% m/m |
|
|
Refined olive oil |
|
£ 0.1% m/m |
|
|
Refined olive-pomace oil |
|
£ 0.1% m/m |
|
|
Blends |
|
£ 0.1% m/m |
|
5.2 |
Insoluble impurities |
|
|
|
|
Virgin olive oil |
|
£ 0.1% m/m |
|
|
Refined olive oil |
|
£ 0.05% m/m |
|
|
Refined olive-pomace oil |
|
£ 0.05% m/m |
|
|
Blends |
|
£ 0.05% m/m |
|
5.3 |
Soap Test |
|
|
|
|
Refined olive oil |
) |
|
|
|
Refined olive-pomace oil |
) |
negative |
|
|
Virgin olive oil |
) |
|
|
|
Virgin olive oil |
) |
not applicable |
|
|
Blends |
) |
|
It is recommended that the product covered by the provisions of this Standard be prepared in accordance with the appropriate Sections of the General Principle of Food Hygiene recommended by the Codex Alimentarius Commission (CAC/RCP 1-1969, Rev. 3-1997).
7. LABELLING
In addition to the provisions of the General Standard for the Labelling of Prepackaged Foods (CODEX STAN 1-1985, Rev. 1-1991), the following provisions shall apply.
7.1 Name of the Food
7.1.1 All products designated as “olive oil” shall conform to the provisions of this Standard for virgin olive or refined olive oil and shall be either virgin olive oil, refined olive oil or a blend of refined olive oil and virgin olive oil.
7.1.2 All products designated as “virgin olive oil” shall conform to the provisions for virgin olive oil.
7.1.3 All products designated as “refined olive oil” shall conform to the provisions for refined olive oil.
7.1.4 All products designated as “refined olive-pomace oil” shall conform to the provisions for refined-pomace oil.
7.1.5 Refined olive-pomace oil shall in no case be described as “olive oil” but shall always be designated as “refined olive-pomace oil”.
7.1.6 Blends of refined olive-pomace oil and virgin olive oil shall be described as “olive-pomace oil”.
7.2 Labelling of Non-retail Containers
In addition to the provisions of the General Standard for the Labelling of Prepackaged Foods (CODEX STAN 1-1985, Rev. 1-1991), the following provisions shall apply to outer containers of a number of prepackaged containers of the products covered by the Standard.
Information on the above labelling requirements shall be given either on the container or in accompanying documents, except that the name of the food, lot identification and the name and address of the manufacturer or packer shall appear on the container.
However, lot identification and the name and address of the manufacturer or packer may be replaced by an identification mark, provided that such a mark is clearly identifiable with the accompanying documents.
8. METHODS OF ANALYSIS AND SAMPLING
8.1 Determination of Fatty Acid Composition
According to IUPAC 2.301, 2.302 and 2.304 or ISO 5508: 1990/5509: 1999.
8.2 Determination of Relative Density
According to IUPAC 2.101, with the appropriate conversion factor. Results are expressed as relative density at 20oC/water at 20oC.
8.3 Determination of Refractive Index
According to IUPAC 2.102.
Results are expressed as the refractive index relative to the sodium D-line at 20ºC.
8.4 Determination of Saponification Value
According to IUPAC 2.202.
Results are expressed in mg KOH/g oil.
8.5 Determination of Iodine Value
According to IUPAC 2.205/1, Wijs method, or ISO 3961:1996
Results are expressed as % m / m absorbed iodine.
8.6 Determination of Unsaponifiable Matter
According to IUPAC 2.401 (part 1-5). Results are expressed as g unsaponifiable matter/kg oil.
8.7 Determination of Bellier Index (CAC/RM 20-1970)
Definition
The Bellier Index of an oil is the temperature at which precipitation of salts of the fatty acids of this oil commences, when the oil has been saponified and made into solution as described under Procedure.
Reagents
The reagents used shall be of recognized analytical reagent quality.
- Aqueous ethanolic potassium hydroxide solution.Aqueous acetic acid solution 1+2 (by volume) so adjusted that 1.5 ml exactly neutralizes (phenolphthalein indicator) 5 ml of the aqueous ethanolic potassium hydroxide solution (8.7.2.1).- 42.5 g of pure KOH is dissolved in 72 ml of distilled water and adjusted to 500 ml with 95% v/v ethanol.
- 70% v/v ethanol solution (use pure ethanol or rectified spirit).
Apparatus
- 220 mm x 26-27 mm test tubes.Preparation of Sample
- Condenser consisting of a glass tube with stopper.
- Thermometer graduated in 1/4° from 8 to 25°C, fixed in a stopper.
To remove water, the oil is decanted and filtered through paper at a temperature slightly above the melting point of certain solid constituents which could separate from the fluid fatty matter.
Procedure
Place 1 ml of oil and 5 ml of the aqueous ethanolic KOH solution into a test tube. Connect to condenser and heat moderately, agitating by rotation from time to time until saponification is completed, i.e. until a perfectly clear solution in obtained. Allow to cool, disconnect condenser and add 1.5 ml of the aqueous acetic acid solution and 50 ml of the ethanol solution. Attach thermometer and homogenize. Place test tube in a beaker of water at 23-25°C. If a flocculent precipitate forms, leave standing for an hour at the same temperature and filter into a test tube. Attach thermometer to the test tube containing the clear solution. Place for a moment in a beaker of water at about 10°C less than the estimated Bellier index. Withdraw and ensure even temperature by inverting a number of times (cooling should be at the rate of about 1°C per minute). Repeat this operation until cloudiness appears. Note temperature. Allow the temperature to increase a few degrees to dissolve the precipitate. Homogenize by inverting test tube over and cool. The cooling should be slow and shaking more frequent as the temperature approaches that noted the first time.
Expression of Results
The Bellier index is the temperature °C at which the cloudiness reappears.
Repeatability
Two parallel determinations may not differ by more than 0.25°C.
8.8 Semi-siccative Oil Tests (CAC/RM 21-1970)
Principle of Method
Based on the reaction between semi-siccative (unsaturated) oils and bromine yielding substances which form an insoluble precipitate at 0°C.
Reagents
The reagents shall be of recognized analytical reagent quality.
- Hexane, or, if not available, light petroleum with distillation point between 40° and 60°C and bromine value less than 1, free of residues.Apparatus- Bromine reagent obtained by adding drop by drop while shaking 4 ml of chemically pure bromine (the presence of chlorine prevents the reaction) into 100 ml of hexane or light petroleum, chilled to 0°C and kept in the melting ice bath until required.
- Stoppered 50-ml Erlenmeyer flask.Procedure
- Bath of melting ice.
The oil to be tested is filtered and dried. Place 1 ml of the oil in the previously dried Erlenmeyer flask and dissolve in 10 ml of hexane. Place the stoppered Erlenmeyer flask in the melting ice bath. After 5 min add 10 ml of bromine reagent in small quantities at a time, while shaking and maintaining the temperature at 0°C. The colour of the solution must clearly indicate excess bromine. Leave the Erlenmeyer flask in the melting ice bath for one hour, after which note appearance of solution. If semi-siccative oil is present, a flocculent precipitate will form varying in quantity according to the percentage of adulteration and the nature of the adulterating oil. The solution remains clear and transparent in the case of genuine olive oils.
Expression of Results
The result is expressed as positive or negative.
8.9 Olive-Pomace Oil Test (CAC/RM 22-1970)
Principle of Method
Based on the temperature of precipitation of salts of the fatty acids after saponification.
Reagents
The reagents used shall be of recognized analytical reagent quality.
- Aqueous ethanolic potassium hydroxide solution. 42.5 g of pure KOH is dissolved in 72 ml of distilled water and adjusted to 500 ml with 95% v/v ethanol.Apparatus- 70% v/v ethanol solution (use pure ethanol or rectified spirit).
- Aqueous acetic acid solution 1+2 (by volume) so adjusted that 1.5 ml exactly neutralizes (phenolphthalein indicator) 5 ml of the aqueous ethanolic potassium hydroxide solution.
- 100 m1 balloon-flask equipped with reflux condenser.Preparation of Sample- 50 ml test tubes.
- Heating arrangement to keep balloon-flask at about 80°C.
- Thermometer graduated from 15° to 60°C.
To remove water, the oil is decanted and filtered through paper at a temperature slightly above the melting point of certain solid constituents which could separate from the fluid fatty matter.
Procedure
Place about 1 g of the oil, prepared as above, into the balloon-flask. Add 5 ml of aqueous ethanol potassium hydroxide solution. Attach condenser and bring to boil holding at this temperature for 10 minutes, shaking from time to time. Allow to cool at ambient temperature. Add 1.5 ml of acetic acid solution and 50 ml of ethanol solution previously heated to 50°C. Mix by shaking, introduce thermometer and allow to cool, noting the appearance of the solution once 45°C in reached. If a flocculent precipitate forms at a temperature above 40°C, the test is positive. Allow to cool to ambient temperature (not lower than 18°C) over at least 12 hours. Observe solution again; the formation of a flocculent precipitate, floating in the middle of the liquid also indicates that the test is positive. A cloudiness not forming into flakes does not indicate the presence of olive-pomace oil.
Expression of Results
The result is expressed as positive or negative.
NOTE: On rare occasions some virgin olive oils, obtained by second pressing, yield a positive result.8.10 Cottonseed Oil Test (CAC/RM 23-1970)
Principle of Method
Based on red colour developed by cyclo-propenoic acids under the operating conditions in the presence of sulphur.
Reagents
The reagents used shall be of recognized analytical quality.
Sulphur reagents: Mix equal volumes of amyl alcohol and a solution of 1 g of sulphur in 100 ml of carbon disulphide.
Apparatus
- 250 mm x 25 mm test tubes.Procedure
- Water bath with constant temperature control.
- Heating apparatus to keep the test tubes at 110o-120o C.
Place approximately 10 ml of the oil under examination into a test tubes add the same volume of sulphur reagent; shake and keep in water bath at 70°- 80°C, shaking until the carbon disulphide has completely evaporated (generally 5 minutes are enough), which is confirmed by the appearance of slight fuming above the liquid. Transfer the test tube to the heating apparatus and keep at 110°- 120°C for 2.hours. A red, or pink colour indicates the presence of cottonseed oil. However, the appearance of an orange colour must not be interpreted as being proof of the presence of cottonseed oil.
Expression of Results
The result in expressed as positive or negative.
NOTE: The heating of the cottonseed oil to a temperature above 170°C brings about a progressive destruction of the cyclo-propenoic acid responsible for the coloration. This destruction in practically complete at 200°C.8.11 Teaseed Oil Test (CAC/RM 24-1970)
Principle of Method
Based on Fitelson (modified Lieberman-Burchard) tests i.e. red colour developed by acetic anhydride in the presence of sulphuric acid in chloroform solution of the oil.
Reagents
The reagents used shall be of recognised analytical quality.
- ChloroformApparatus
- Concentrated sulphuric acid (d = 1.84)
- Acetic anhydride
- Diethyl oxide
- 150 mm x 15 mm test tubes.Procedure
- 2 ml pipette, graduated in tenths.
- Dropper so calibrated that 7 drops of oil weigh approximately 0.22 g.
- Water bath at 5oC.
Using the graduated pipette, place 0.8 ml of acetic anhydride, 1.5 ml of chloroform and 0.2 ml of sulphuric acid in a test tube. Cool to 5°C, then add approximately 0.22 g of oil. If cloudiness appears add acetic anhydride drop by drop with shaking until the solution becomes clear. Keep at 5°C for 5 minutes. Add 10 ml of diethyl oxide previously cooled to 5°C. Stopper the test tube and mix immediately by inverting it twice. Return the test tube to the bath at 5°C and observe the colour. After about one minute a red colour will appear if tea oil is present.
Expression of Results
The result is expressed as positive or negative.
NOTE: A pink colour shall be regarded as negative, since some olive oils yield this colour.8.12 Sesameseed Oil Tests (CAC/RM 25-1970)
Principle of Method
Based on the detection of sesamoline, a glycoside, and sesamine, a complex cyclic ether, which are present in small amounts in sesameseed oil.
8.12.1 Detection of Sesamoline
Reagents
The reagents used shall be of recognized analytical quality.
- Concentrated hydrochloric acid (d = 1.18).Apparatus
- Solution of 2% v/v freshly distilled furfural in 95% v/v ethanol.
Graduated 50-m1 stoppered test tube.
Procedure
Place 10 ml of the oil and 10 ml of conc. hydrochloric acid in the graduated test tube. Stopper and shake vigorously for 30 seconds. Allow to stand. Add 0.5 ml of the solution of furfural. Stopper and shake again. Allow to stand until decantation. If the lower layer does not turn red, the test is negative. If a red coloration appears, add 10 ml of water and shake gently and allow the liquid to settle. If the coloration disappears, the test is negative. If the coloration remains, the test is positive. Refined sesame oils do not always give a positive reaction by this method.
Expression of Results
The result is expressed as positive or negative.
8.12.2 Detection of Sesamine
Reagents
The reagents used shall be of recognized analytical quality.
- Concentrated sulphuric acid (d = 1.84).Apparatus
- Solution of freshly distilled furfural in acetic anhydride, 0.35/ml v/v.
- 25-ml, stoppered graduated test tube.Procedure
- Decanting beaker approximately 50-ml.
- Flat-bottomed porcelain dish approximately 60 mm in diameter.
Place 10 ml of the oil and 5 ml of the solution of furfural in the test tube. Stopper and shake vigorously for approximately one minute. Pour the mixture into the decanting beaker and allow to settle. Transfer a portion of the deposit into the dish and add 6 or 7 drops of sulphuric acid. Mix by shaking the dish gently.
The test is positive if a greenish-blue colour appears. Sesame oils, even when refined, give a positive reaction.
Expression of Results
The result is expressed as positive or negative.
8.13 Determination of the Sterol Content
According to IUPAC 2.403.
Results expressed as % of the sum of beta-sitosterol, campesterol and stigmasterol.
8.14 Determination of the Fatty Acids in the 2 Position
According to the IUPAC method (1979, 6th edition) no. 2.210. “Determination of the Fatty Acids in the 2-position in the Triglycerides of Oils and Fats”.
The saturated fatty acids at position 2 means the sum of palmitic (16:0) and stearic (18:0) acids expressed as a percentage m/m of the total fatty acids at position 2.
8.15 Determination of Free Acidity
According to IUPAC 2.201.
Results are expressed as % m/m oleic acid and/or as the number of mg KOH required to neutralize 1 g oil.
8.16 Determination of Peroxide Value
According to IUPAC 2.501 or ISO 3960:1998
Results expressed as milliequivalents active oxygen/kg.
8.17 Determination of Specific Extinction in Ultra-Violet (CAC/RM 26-1970)
Principle of Method
The degree of oxidation of olive oil is reflected by its specific extinction at 232 nm and 270 nm. In fact, virgin olive oils, of good quality and correctly stored, contain very few products of oxidation; these mainly peroxidic in nature, have a maximum absorption at approximately 232 nm. The values of E ë, at 232 and 270 nm in such olive oils are below the maximum provided for in the standard. On the other hand, when the oil is treated with a decolourising agent (i.e. an absorbent earth) during the refining process, conjugated trienoic compounds are formed. These compounds have a maximum absorption situated at approximately 270 nm; this means that refined oils have higher values of E l at 270 nm.
NOTE: Measurement of specific extinction in ultra-violet is essentially a measurement of the state of alteration of the oil. It is not specifically a measurement of the refining. In some particular cases, abnormally altered virgin oils can show spectral characteristics close to those of refined oils.Reagents
- Spectrophotometrically pure cyclohexane: Minimum transmittance at 220 nm: 40% and minimum transmittance at 250 nm: 95% by comparison with distilled water.Basic alumina of Brockmann grade 1 (0% water) is obtained by heating for 3 hours at 380-400ºC basic alumina (chromatographic quality) of particle size 30? to 130 ì (mean 80 ì). To 100g of this product add 5 ml of distilled water to produce basic alumina of Brockmann grade close to IV.- Basic alumina of known grade
NOTE: Method used to check the activity index of the alumina.Place 30 g of the basic alumina (as obtained above) in a chromatographic column, 450 mm long with a diameter of 35mm; through this column pass, under the conditions laid down in the method, a mixture of 95% virgin olive oil, having a specific extinction coefficient below 0.18 at 270 nm, and of 5% arachis oil previously treated, during the refining process, with decolourising agent (absorbent earth) and having a specific extinction coefficient equal to or above 4 at 270 nm. If this mixture shows a specific extinction coefficient greater than 0.11, the activity of the alumina is acceptable. Should the elution of conjugated trienes not have taken place using this alumina, an alumina at a higher hydration should be used after verifying that it agrees with the preceding test.
Apparatus
- Ultra-violet spectrophotometer for measurements between 210 and 300 nm.Adjustment of Spectrophotometer: dissolve 0.2 g of dry potassium chromate in exactly 1 litre of a 0.05 N solution of potassium hydroxide. Place exactly 25 ml of this solution in a 500-ml flask and bring up to the 500-ml mark with the 0.05 N solution of potassium hydroxide. Determine the optical density of this latter solution by comparison with the 0.05 N solution of potassium hydroxide as a reference solution, in a 1 cm cell. This, at 275 nm should be 0.200 ± 0.005.
- Quartz cells of 1cm thickness.
- 50-ml and 500-ml volumetric flasks.
- Chromatographic column, 450 mm long with a diameter of 35 mm.
Procedure
If the oil is not completely clear at ambient temperature, filter before attempting measurements. Place approximately 0.5 g, weighed accurately, of the oil in the 50-ml flask. Add the cyclohexane up to the mark and shake. Fill a cell with this solution and measure the optical density using the cyclohexane as a reference solution. Make determinations at 232 and 270 nm. Determine, in the region of 270 nm, the wavelength of the maximum absorption lm and determine the optical density at lm nm, lm-4 nm and lm +4 nm.
Calculation and Expression of Results
Calculation of Specific Extinction at 232 and 270 nm
where:
E l = specific extinction at wavelength l nmCalculation of the variation of the specific extinction at the wavelength of maximum absorption near 270nm
A l = optical density at wavelength l nm
c = concentration of the test solution in g/100 ml
l = thickness of the cell in cmNOTE: If the optical density is less than 0.2, re-measure with a more concentrated solution. If it is more than 0.8, re-measure with a weaker solution.
Where:
DE = variation of specific extinction at l mAdditional procedure for determination of the specific extinction after passage through alumina
E lm= specific extinction at the wavelength of maximum adsorption near 270 nm.
E lm-4 and Elm+4 = specific extinctions at wavelengths plus l m plus or minus 4 nm.
Place 30 g of basic alumina (as in the reagents section earlier) in a chromatography column approximately 450 mm long and 35 mm in diameter, furnished with a draining tube of about 10 mm diameter. Pack the alumina mechanically by repeatedly tapping the column, held vertically, on a wooden surface. Place in the column thus prepared 100 ml of a solution of 10 % oil in hexane. Collect the drainings and evaporate the solvent in a vacuum at less than 25°C. Using the oil so obtained, immediately determine the specific extinction at 270 nm, as previously described.
8.18 Determination of Alpha-Tocopherol
According to IUPAC 2.404 “Identification and determination of tocopherols”, method A.
Results are expressed as mg tocopherol/kg oil.
8.19 Determination of Matter Volatile at 105°C
According to IUPAC 2.601 or ISO 662:1998. Results are expressed as % m/m.
8.20 Determination of Insoluble Impurities
According to the IUPAC 2.604. Results are expressed as % m/m.
8.21 Soap Test (CAC/RM 27-1970)
Principle of Method
Detection of alkalinity using bromophenol blue as indicator.
Reagents
- Solution of 0.10 of bromophenol blue in 96º v/v ethanol.Apparatus- Freshly distilled acetone, 20 v/v water content.
- A few drops of the solution of bromophenol blue should give a yellow to yellow-green colour to the acetone with 2% water.
150 mm x 15 mm test tube.Procedure
Place 10 ml of the acetone and 1 drop of the bromophenol blue solution in a test tube. The solution should have a yellow colour. If not, rinse the test tube with acetone until the blue colour disappears. Place 10 g of the oil in the test tube, stopper with a clean stopper, shake and allow to settle. The presence of blue colour in the upper acetonic layer indicates the presence of soap.
Expression of Results
The result is expressed as positive or negative.
