الزيوت والدهون ومنتجاتها: معايير الجودة وطرق كشف الغش باستخدام أجهزة التحاليل الحديثة

By

: الزيوت والدھون ومنتجاتھامعايير الجودة وطرق كشف الغش باستخدام أجھزة التحاليل الحديثة

Fats, Oils and their Products: Purity Criteria and Detection of Adulteration by using the Modern of

Analytical Methods

By

Dr. Adel Gabr Abdel-RazekAssociate Professor

Fats and Oils Dept.

Food Technology and Nutrition Division

National Research Centre

9 April 2014

١Dr. Adel Gabr Abdel-Razek Detection of Adulteration NIS Workshop

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Importance of Fats and Oils•Essential FA•Vitamins•Energy * **•Biological activity• 30 % WHO, AHA Balance•Food products•Food products

٢Dr. Adel Gabr Abdel-Razek Detection of Adulteration NIS Workshop


ANALYTICAL CRITERIA FOR QUALITY

AND PURITY EVALUATION OF EDIBLE OIL

Quality criteriaFats and Oils Quality is the physical and chemical properties of fats or oils that are necessary for any specific purpose as stated in a producta product

A. Hidden 1.Free acidity 2.Absorbency in ultraviolet 3.Peroxide value 4.Moisture and volatile matter5.Insoluble impurities in light petroleum 6.Trace metals

٣Dr. Adel Gabr Abdel-Razek Detection of Adulteration NIS Workshop


B. Sensorial

7.Organoleptic assessment (applicable only to virgin olive oils)

٤Dr. Adel Gabr Abdel-Razek Detection of Adulteration NIS Workshop


Purity Criteria :A. Detection of other vegetable oils.

٥Dr. Adel Gabr Abdel-RazekDetection of Adulteration NIS Workshop


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Dr. Adel Gabr Abdel-Razek Detection of Adulteration NIS Workshop


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Detection of Adulteration of Vegetable Oils

Based On:

TraditionalChemical Methods

Chemical and Physical

Properties Oil Constituents

Spectroscopic

Methods

Recent Methods

of Analysis

*Artificial mustard Oil

*Argemone oil added to mustard oil

*Linseed oil (Hexabromide)

*Cottonseed oil (Halphen’s)

*Castor oil (Molybdate test)

*Palmolein in groundnut oil

I.V, S.V, R.I, density and

viscosity.Major

Components

* Fatty acids

* Triacylglycerols

Minor Components

* Tocols (Vitamin E)

* Sterols

* Fatty alcohols

* Phenols, lignans and flavonoids

* Hydrocarbons

* Other Minore Components

NMR, FTIR, etc..... *NMR spectroscopy with

Multivariate classification

*Gold Nanoparticles and Spectrophotometric

*plastid based molecular DNA technology

٨Dr. Adel Gabr Abdel-Razek Detection of Adulteration NIS Workshop


Detection of adulteration

of vegetable oilsDue to the increasing health awareness of peoplearound the world, people are looking for healthy food.Unfortunately, a lot of the food available in the marketis either unhygienic or contaminated with harmfulis either unhygienic or contaminated with harmfulingredients. One of the many problems that face theconsumer is adulterated foods.

٩Dr. Adel Gabr Abdel-Razek Detection of Adulteration NIS Workshop


Definition of adulteration

Adulteration: is that the deliberate contamination of

food material with low quality, cheap and non-edible or

toxic substances is called food adulteration.

� Types of adulteration� Types of adulteration

� Deliberate: Expensive oils that get adulterated withthe cheaper one.

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Accidental: Accidental contamination is hard to avoid in modern

bulk handling installations, where oils of different qualities must

be pumped through common valves and pipelines.

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١٢Dr. Adel Gabr Abdel-Razek Detection of Adulteration NIS Workshop


� Adulteration brings a lot of easy money

for the traders.

� The traders use it for their economic benefit

without thinking about its effect on the consumers.

� Substitution or adulteration of a product with a cheap� Substitution or adulteration of a product with a cheapingredient is not only a major economic

fraud but may also have severe health

implications to consumers.

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Dr. Adel Gabr Abdel-RazekDetection of Adulteration NIS Workshop


For example: In Spain, some 400 deaths and 20, 000 casualtieshave occurred since May 1981 from the disease now known as‘’Spanish toxic syndrome’’, which is caused by the consumptionof adulterated cooking oil.

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Detection of adulteration of vegetable oils�Traditional chemical methods for detection of

adulteration

� To detecting and quantifying such adulteration, many simple methods are applied in routine laboratory analysis.analysis.

� Most of these methods are based on the development of characteristic colour or appearance turbidity/precipitate.

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�Detection of synthetically made artificial mustard Oil.

�Detection of argemone oil added to mustard oil.

�Detection of rice bran oil.

�Detection of sesame oil (Baudouin test).

�Detection of linseed oil (Hexabromide test).�Detection of linseed oil (Hexabromide test).

�Detection of cottonseed oil (Halphen’s test).

�Detection of castor oil (Molybdate test).

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�Detection of adulteration based on chemical and physical properties of vegetable oils.

� They include the iodine value, saponification value, � They include the iodine value, saponification value, colorimetric reaction as well as refractive index, density and viscosity.

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�Oil constituents (chemical components of oils).

� Vegetable oil is a very complex mixture (thousands of chemically distinct components), with fatty acids and triglyerides as major constituents, and tocopherols, triglyerides as major constituents, and tocopherols, sterols, alcohols, wax esters, etc. as minor constituents.

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١٩Dr. Adel Gabr Abdel-Razek Detection of Adulteration NIS Workshop


�Detection of adulteration based on major

components

�Fatty acids

� Routine testing of the purity of edible oils and fats is primarily based on the determination of the fatty acid composition.

Palmitic acid is used as an indicator of adulteration of � Palmitic acid is used as an indicator of adulteration of cottonseed oil by palm olein.

� Linoleic acid content is a good indicator of purity if groundnut and sunflower oils are suspected of being adulterated with cheaper soybean or rapeseed oils.

� Erucic acid is used to detect if expensive oil adulterated with rapeseed oil.

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�Triacylglycerols (TAG)

� TAG composition has also been established as a measurement of the quality and purity of vegetable oils. oils.

� Determination of TAG content in olive oil is useful for verifying the presence of small quantities of other vegetable oils.

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� The Codex standard for olive oil products aredetected by observing the maximum differencebetween the actual and theoretical ECN42 TAG(0.2 for virgin olive oil).

� The presence of any significant level of trilinolein(LLL) in olive or other oils relatively low in linoleic(LLL) in olive or other oils relatively low in linoleicacid can show the presence of more unsaturated oils (e.g. soybean or sunflower).

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� Detection of adulteration based on

minor components

� The analysis of minor components is a useful method of detecting adulteration of some edible oils.

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�Tocopherols and tocotrienols (Vitamin E)

�Tocopherols and tocotrienols (tocols) natural antioxidants compounds, which give stability to oils, vary from one edible vegetable oil to another.

�Tocols are absent from animal fats but they are normally present in crude vegetable oils.normally present in crude vegetable oils.

�The analysis of tocopherols can be used to detect adulteration of oil.

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�In sunflower and olive oils, α-tocopherol is the main tocopherol present, but for some oils, e.g. soybean oil, relatively high levels of γ- and δ-tocopherols may be present, so some examples of adulteration may be detected on this basis.

�Both palm oil and grape seed oil are relatively unusual in containing significant levels of tocotrienols, which in containing significant levels of tocotrienols, which are absent or present at much lower levels in most vegetable oils.

�The tocopherol composition or high levels of tocopherols may help to indicate adulteration when considered with other analytical data.

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�Sterols

� Sterols, which comprise a major portion of the unsaponifiablematter.

� Sterols are found in all fats and oils, .� Sterols are found in all fats and oils, .

� Sterols are also characteristic of the purity of vegetable oils

� for example:

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�Rapeseed oils contain significant levels of brassicasterol.

�Olive oil has high levels of β-sitosterol and -Δ5-avenasterol.

�Safflower and sunflower oils have high levels of Δ7-stigmastenol.stigmastenol.

� These apparent differences make them the most suitable for detecting adulteration/ contamination among vegetable oils.

٢٧Dr. Adel Gabr Abdel-Razek Detection of Adulteration NIS Workshop


�The detection of adulteration of vegetable oils with animal fats can be achieved by analysis of the cholesterol content, since this sterol is either absent or present at very low concentrations in vegetable oils.

�As with adulteration of virgin olive oil with refined olive oil, this type of adulteration may be detected by analysis of sterol degradation products.

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�Fatty alcohols�Long chain alcohols, known as fatty alcohols, are

present only in very small amounts in vegetable oil but are found in greater quantities in some marine oils.

�Fatty alcohols are low in virgin olive oil, but it is much higher in solvent extracted grades of olive oil and this has been accepted as a method of detecting adulteration of pressed olive oil.

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�Phenols, lignans and flavonoids

�The analysis of phenols, lignans and flavonoidscomponents are useful method of detecting adulteration of some pressed oils.

�Pressed oils contain a range of phenols including flavonoids.

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�Hydrocarbons

�Most oils contain low levels of hydrocarbons.

Olive oil contains reasonable amounts of hydrocarbon�Olive oil contains reasonable amounts of hydrocarbon

�Olive oil can clearly be differentiated from other vegetable oils on the basis of hydrocarbon components.

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�Other components�Detection of hazelnut oil in olive oil is difficult by

analysis of TAGs, fatty acids, sterols or tocopherols

�The presence of (E)-5-methyl-hept-2-en-4-one�The presence of (E)-5-methyl-hept-2-en-4-one(filbertone) gives pressed hazelnut oil a characteristicaroma, and the detection of this component by GC–MS

�The differences in the minor non-volatile componentsthat can be used for the detection of adulteration ofvegetable oil.

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�Spectroscopic methods

�Spectroscopic methods have the following advantages:

�rapid analysis, direct, non-invasive and non-destructive, in situ analysis, qualitative anddestructive, in situ analysis, qualitative andquantitative analysis, economic method (laboursaving), sample preparation steps are normally keptto a minimum and no use pollutant solvents.

�NMR spectroscopy.

�Fourier transform infrared (FTIR) spectroscopic technique.

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�Recent methods of analysis�A combination of a high-power gradient diffusion

NMR spectroscopy with multivariate classification method.

�A new method, based on the formation of gold �A new method, based on the formation of gold nanoparticles (AuNPs) and spectrophotometricanalysis.

�A simple reproducible and economically feasible plastid based molecular DNA technology.

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�Conclusion�The interest of researchers in the authentication of

vegetable oils has led to an improvement in the control ofadulteration. Most of the resulting issues andmethodologies are described in the official methods andtrade standards published by the Association of AOAC,trade standards published by the Association of AOAC,AOCS, IOOC and IUPAC.

�There are sophisticated methods of analysis, however, theinstruments required are too expensive and beyond reachof a mediocre industrialists, but we can not overlookimportance and utility of some of the more traditionaltestes in detecting the presence of specific oils in suspectedblends.

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�Future Trends�All the informations should be obtained on

defined number of authentic samples.

�Advanced techniques should a wide range ofapplications in vegetable oils and adulterationapplications in vegetable oils and adulterationstudies and they used routinely and incombination with other chemical criteria.

�The rapid development of techniques shouldcouple of spectroscopy with chromatography.

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�One and multidimensional methods incombination with chemometric methodsshould be, successful in detecting adulteration.

�No doubt that continued progress in theapplication of the computer aidedmathematical and statistical techniques willmathematical and statistical techniques willenhance the power chromatographic andspectral analysis and lead to greater ease inthe rapid detection of vegetable oiladulteration.

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� From the above mentioned it is clear that,the important of the different techniquesnever stop and future will witness morenever stop and future will witness moreprecise techniques and instrumentationthat can help in discriminating andquantifying the adulteration of vegetableoils.

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Thanks

for

Your

Attention٤١
