IDENTIFICATION AND FALSIFICATION OF VEGETABLE OIL
Just think: a few years ago, a Russian buyer had no problems with the choice of vegetable oil. On the shelves there were only sunflower, corn and sometimes olive. And now, when the eyes run up from the names and manufacturers on offer, the consumer and expert merchandise experts need fundamental knowledge to understand this diversity.
In the market of vegetable oil, which is always popular with the Russian consumer, since it is also added to salads and is widely used for frying, it is sometimes difficult for a buyer to choose a quality oil from a widely advertised low-quality one. Therefore, both the manufacturer and the distributor are tempted to fake or increase their sales by substituting one type of oil for another, less valuable.
In addition, today not only edible oil is supplied to the market, but also technical oil, technologically processed for food. Therefore, there are problems with conducting a comprehensive examination of the authenticity of all types of vegetable oils sold in the food markets of Russia.
When carrying out an examination of the authenticity of vegetable oils, the following research objectives can be achieved:
♦ identification of the type of vegetable oil;
♦ identification of the variety of vegetable oil;
♦ ways of falsification and methods of their detection.
When carrying out an examination of the authenticity in order to identify the type of vegetable oil, the expert must be familiar with modern research methods for this group of goods, and then determine for himself the range of tasks he solves, based on his level of knowledge in this area. Consider the range of tasks to be solved that a professional expert may have to achieve this goal.
Identification of vegetable oils. Vegetable oil is a ready-to-eat product obtained from seeds or embryos of seeds, fruits of plants by pressing and / or extraction and purified from certain impurities, depending on the type of product obtained.
By the type of fat-containing raw materials, vegetable oil is produced: sunflower, corn, mustard, cottonseed, soybean, peanut, olive, sesame (sesame), coconut, palm kernel, palm, cocoa butter, rapeseed.
According to the degree of suitability for consumption and biological value for food, liquid vegetable oils are arranged in the following order: corn, olive (Provencal), mustard, sunflower, sesame, soybean, peanut, olive (wood), cottonseed, rapeseed, mixtures of various oils.
According to the degree of purification and, accordingly, a decrease in nutritional and biological value, vegetable oils are arranged in the following sequence: unrefined, hydrated, refined non-deodorized, refined deodorized, neutralized non-deodorized, neutralized deodorized.
Unrefined oil contains: triglycerides, free vitamin-like fatty acids (oleic, linoleic, linolenic), phosphatides, fat-soluble vitamins (A, E, K), wax, carotene, aromatic substances and other compounds.
The hydrated oil retains: triglycerides, free vitamin-like fatty acids, fat-soluble vitamins, waxes, carotene, aromatic substances, etc.
In refined non-deodorized oil, only triglycerides, aromatic substances are preserved.
Only triglycerides remain in refined deodorized oil. It is a raw material for the production of margarine and cooking oils and for frying.
The identification indicators of various varieties of vegetable oils are: color number; acid number; moisture content, phosphorus-containing and unsaponifiable substances; sludge by weight.
The examination of authenticity can also be carried out in order to establish a method of falsification of vegetable oils, while there may be the following methods and types of their falsification.
Assortment falsification of vegetable oils can occur due to: re-grading; substitution of one type of oil for another.
A re-grading of vegetable oils is widespread, very often highly refined vegetable oils are substituted for unrefined and even technical types of oils. Thus, unrefined rapeseed oil should not be used for food. Moreover, rapeseed oil contains specific substances that give bitterness to cruciferous plants (cabbage, radish, rapeseed), which are called glycosinolates. These are complex compounds consisting of carbohydrate, sulfur-containing, disulfide and other parts. Practically nobody in the Russian Federation can determine these compounds. However, the certificates of conformity for rapeseed and rapeseed products indicate that the products are certified for these compounds. This is a classic example of the profanation of certification services.
For these compounds, no one controls the quality of rapeseed oil, and it is probably directly used in the widely advertised refined vegetable oils of unknown origin.
More valuable types of oils can also be replaced: corn, sunflower - low-value soybean, cottonseed, rapeseed, etc.Moreover, in a refined form, when specific aromatic and coloring substances have been removed, it is almost impossible to distinguish them from one another in terms of organoleptic characteristics. It is possible to establish their origin only by physical and chemical indicators (see Table 34).
High-quality falsification of vegetable oils can be achieved in the following ways: violation of production technology; violation of the recipe composition; violation of cleaning technology.
There is a danger that the vegetable oil obtained from seeds that have not undergone high-quality cleaning may contain harmful impurities that give the oils a bitterness, resinous taste. For example, poor cleaning of sunflower seeds on primitive technological lines leads to the fact that seeds damaged by worms, with a coating of resin, etc. are not separated. Therefore, the resulting low-quality oils are often passed off as high-quality or they have to be refined.
Finally, there are types of vegetable oils (among them cottonseed, rapeseed, soy), which cannot be eaten without refining at all, since they contain various toxic substances. So, in cottonseed oil there is a strong poison - gossypol, which is removed only when neutralized with anthranilic acid or high heat treatment. Probably, this is where the ancient tradition of Asian peoples originates: when preparing pilaf, cottonseed oil is strongly and for a long time calcined.
Since high-quality Provencal olive oil comes to Russia at a high price, and the demand for this oil is fueled by unhealthy excitement, allegedly by the fact that it has medicinal properties, many manufacturers buy wooden olive oil and dilute it with sunflower, soybean, rapeseed, cottonseed and others. low-quality refined vegetable oils.
There is also a gross falsification, when oils intended only for technical purposes, for example, castor oil, unrefined sunflower 2 grades, etc., are sold as food oils.
Abroad, and at some of our oil extraction plants, the extraction of vegetable oils with gasoline is widely used. With this method of obtaining oils in the cake, fats and fat-like substances practically do not remain, and after pressing, usually from 6 to 13% remains. However, the oil obtained by extraction must necessarily be refined and deodorized so that no traces of gasoline remain. This oil is usually used to make margarine or cooking oils, but very often it is sold as refined deodorized oil.
The shelf life of vegetable oils is only: 4 months - for corn and sunflower, 8 months - for mustard, peanut - up to 6 months. To lengthen the shelf life, not preservatives, but antioxidants are introduced into vegetable oils. But all manufacturers of vegetable oils do not write about these additives on the packaging.
Quantitative falsification of vegetable oils (body kit, measurement) is a deception of the consumer due to significant deviations in the parameters of the can (mass, volume), exceeding the maximum permissible deviations. For example, the net weight of a bottle with vegetable oil is less than what is written on the package itself, or the volume of sunflower oil sold is reduced by reducing the volume of a measuring cup by 1 liter. It is quite simple to identify such a falsification by first measuring the net weight of a bottle with vegetable oil or the volume with verified measuring measures of weight, volume.
Information falsification of vegetable oils is a consumer deception with the help of inaccurate or distorted information about a product.
This type of falsification is carried out by distorting information in shipping documents, labeling and advertising. For example, refined oil, in principle, cannot contain fat-soluble natural vitamins, and the advertisement for Zlato oil claims that this oil contains it. This is a common information falsification.Many vegetable oil packages also indicate that it does not contain cholesterol. But all types of vegetable oil have never contained cholesterol, since this substance is synthesized only by animal organisms. This information misleads the common consumer and is just a publicity stunt.
When falsifying information about vegetable oils, the following data are often distorted or inaccurately indicated:
♦ name of the product;
♦ manufacturer of the goods;
♦ quantity of goods;
♦ introduced food additives - antioxidants.
If in front of you is vegetable sunflower, corn oil, olive oil with the addition of sunflower with a shelf life of more than 4 months and the antioxidant additives (butyloxytoluene, butyloxyanisole) are not indicated on the package, then before you is another fake.
Also, remember that only premium and first grade oils are intended for consumption. If it says on the packaging that this is 2nd grade oil, then this is also a fake.
Information falsification also includes falsification of a quality certificate, customs documents, a bar code, the date of production of vegetable oils, etc.