How do free fatty acids behave? How is the iodine value defined? Where does the dropping point lie? Here is a list of specialist terminology to browse through.
The oxidation susceptibility is defined by the peroxide value (PV) that an oil/fat has after having been thinly spread on an open glass saucer and kept at 50°C for 48 hours.
Freshly refined oils, which have been obtained from perfect seeds, do not contain any oxygen bound as peroxides (PV < 0.1) and contain a significant amount of natural anti-oxidants. The oxidation susceptibility (0-1) rises only imperceptibly.
Freshly refined oils, obtained from old or spoiled seeds, also have a peroxide value of 0 or a little higher. The oxidation susceptibility (5-20) of these oils is often higher because the natural anti-oxidants have been destroyed.
Native unrefined oils, like virgin olive oil, form an exception to this. The PV of these oils is at most to 5 to 20. The oxidation susceptibility is only a little higher. As the natural anti-oxidants are still present in the oil, the alteration susceptibility rises only very slowly. No statement can be made about the quality of these oils based on the oxidation susceptibility and peroxide value.
Carbohydrates or saccharides are a large class of foods. Carbohydrates are generally understood as being sugar and starch. Carbohydrates, together with fats and proteins, form the largest quantity of usable (including starch) and unusable (fibres) proportion of food.
Apart from their central role as physiological energy carriers, they play an important role as a structural substance, above all in the plant kingdom. A distinction is made between:
• Monosaccharides (simple sugars),e.g. glucose, fructose disaccharides, e.g. granulated sugar, lactose, malt sugar
• Oligosaccharides (multiple saccharides), e.g. melitose
• Polysaccharides, e.g. starch, cellulose, chitin
Monosaccharides are formed from carbon dioxide and water in photosynthesis and contain carbon, hydrogen and oxygen. They are then linked to form polysaccharides for storage and to build cells. Animals and people can also form long-chain saccharides from monosaccharides. As the brain cannot convert fats directly into energy, it is dependent on a sufficient supply of glucose to do so.
Cholesterol is a nutritional fat and is one of the basic substances of the human organism. The fat-like molecule occurs in almost all tissues of the body and is essential for different metabolic processes.
Apart from the body's own cholesterol produced in the liver, we also ingest cholesterol through food – particularly through animal fats, like butter, fatty types of sausage and offal.
As a fat-like substance, cholesterol is primarily insoluble in the blood. The body needs carrier substances to carry cholesterol into the individual cells that process the cholesterol, which explains why cholesterol is packed in water-soluble protein membranes, known as apoproteins. The combination of apoprotein and fat (lipid) produces water-soluble lipoproteins, which are formed in the liver and transport cholesterol through the blood vessels to the body's cells.
The dropping point is the temperature at which the first drops of melting fat drip from the collection vessel.
The dropping point is an important characteristic for describing the melting properties of oils and fats. Fats with fast melting properties, which for example are used in the chocolate or ice cream industry, have a dropping point of between 25 and 38°C, depending on their use. These fats produce a pleasant feel in the moth, as the melting range lies close to or below body temperature.
Fats with slow melting properties, which for example are used in the pastry or soup industry, have a dropping point of between 38 and 48°C. These fats offer important benefits in products, in which a dry consistency is called for (no leakage of oil or grease).
Edible fibres influence the metabolism and digestion organs. The precise effect depends on their structure.
Vegetable and plant fibres include cellulose, lignin and pectin, while fibres with an animal origin include collagen and gelatine, bone and skin. Fibres cannot be used by the metabolism. The majority of them are excreted unaltered by the body, while a small remaining proportion ferments in the large intestine. The waste products produced by bacterial fermentation can be used by the body.
Folic acid is essential for blood formation and an increased supply is crucial in pregnancy. Larger amounts of folic acid also control the homocysteine level and thus affect the health of the coronary and brain arteries.
There is a general lack of folic acid in Europe. Nutritional scientific societies in Germany, Austria and Switzerland recommend a daily amount of 400 µ/day for adults and 600 µ/day for pregnant women and breastfeeding mothers. However, the actual quantity of folic acid ingested is much lower. Numerous studies have shown that a higher consumption of folic acid has a positive effect on health. The richest vegetable sources of folic acid are wheat germs. Florin has developed a vegetable oil containing folic acid for the Swiss supermarket chain Migros: actilife Oliraplus.
Fractionation is the physical separation of fats into individual fractions by slow cooling. This causes melting fats (stearins) to crystallise at higher temperatures, which can then be separated from the fats that melt at a lower temperature (oleins).
The fractions obtained in this manner have specific properties, which can have key functions in unhardened fats.
A special case of fractionation is winterisation, during which troublesome substances (e.g. waxes) are removed, which cause oils to become turbid when stored in the refrigerator.
The Swiss Food Manual describes free fatty acids as the proportion of oleic, lauric or palmitic acid in 100 g of fat or oil, calculated in grams.
Chemically speaking, fats and oils are connections between glycerol and fatty acids.
To determine the percentage of fatty acid, solvent is added to the oil or fat in a first step. Sodium hydroxide is then added to the sample until all the free fatty acids have been neutralised. The content of free fatty acids can be calculated based on the quantity of sodium hydroxide needed to fully neutralise the sample.
The content of free fatty acids is an important quality feature. The lower the content, the better is the stability in storage and thus the shelf life of the oil or fat. With crude pressed oils, the percentage lies between 0.1 and 3%, whereas with refined oils it is between 0.01 and 0.1%.
Determining the free fatty acids when assessing olive oils is one of the most important criteria alongside their organoleptic characteristics.
GC analysis is a process for determining the fatty acids in edible oils and edible fats, which contain compounds of glycerol and fatty acids. The type of fatty acid is characteristic of the respective type of oil and fat.
The fatty acid methyl esters are injected onto a capillary column 20 to 100 m in length and 0.01 mm in diameter in a gas chromatograph. The fatty acid methyl esters pass through to the end of the column under a pressure of around 5 bar. As the different fatty acid methyl esters have different retention times in the column, the retention time enables the type and quantity of fatty acid to be determined.
The purity of the products is analysed on the basis of the fatty acid spectrum. The proportions of saturated, unsaturated and polyunsaturated fatty acids is calculated from the fatty acid content for the purposes of declarations.
Liquid oils are characterised by a relatively high percentage of mono- and polyunsaturated fatty acids, while solid fats have higher percentages of saturated fatty acids.
To give an oil a more solid consistency, part of the oil is converted into solid fat by accretion of hydrogen onto the unsaturated fatty acids, which produces saturated single bonds from the unsaturated double bonds. This process is known as hydrogenation or hardening. However this process produces trans-fatty acids, which can have negative effects on health.
Oil and fat is heated to 120/130°C and exposed to a defined air flow in a special measuring unit (rancimat). Oxidative, volatile substances form under these conditions, which can be captured and detected in a vessel with distilled water.
The induction time is an important characteristic for describing the stability of an oil or fat. The longer the induction time, the more stable are the oils and fats.
The iodine value indicates the quantity of iodine, which – under the described test conditions – is absorbed by 100 g of fat.
Iodine and solvent are added to the fat to be analysed. A proportion of the quantity of iodine added is absorbed by the unsaturated fatty acids (double bonds). This missing amount of iodine is then titrimetrically measured.
The iodine value is used to determine the percentage of unsaturated acids present. The higher this percentage, the higher will also be the iodine value. However, the iodine value is declining in significance, as this number cannot differentiate whether the fatty acids are mono- or polyunsaturated.
The word calorie comes from the Latin word "calor" meaning heat.
A calorie (cal) is an old-fashioned unit of measure for thermal energy. It is still used to indicate the energy content in foodstuffs (calorific value) or the energy turnover by people when doing different activities, like sport.
1 calorie is the thermal energy needed to heat 1 g of water by 1 Celsius from 19.5°C to 20.5°C.
1000 cal = 1 kcal
1000 times the amount of energy is needed, i.e. 1000 cal = 1 kcal, to heat 1000 g = 1 kg of water by 1°C.
The following paper, which can be downloaded, contained detailed information on 3-MCPD esters, including a statement by Florin AG:
Mould and toadstools (multi-celled) and yeast (single-cell) belong to the family of fungi.
Fungus is widespread in nature and accordingly has great significance for the environmental equilibrium. Fungus has a very complex metabolism , which enables it to use and decompose nutrients under suitable conditions (humidity, oxygen content etc.). It also aids the production of food: mould is used in the production of some sorts of salami, edible mould aids cheese maturing or enhances the flavour of certain types of cheese.
The special characteristics of every foodstuff – water content, nutrient composition, consistency etc. – only offer a source of life to certain types of fungus. We rely on processes using drying or the binding of moisture, such as curing meat, boiling fruit with sugar or pickling food in vinegar, to preserve foodstuffs. Too high concentrations of mould in the environment can trigger infections or allergic reactions.
The peroxide value is a measure of the amount of oxygen chemically contained in a fat or oil as peroxide (especially hydroperoxides). It is expressed as milliequivalents of active oxygen contained in 1 kg of fat.
Fundamentally oils and fats are substances that oxidise easily. Peroxides are produced if oxygen builds up on fat molecules. This reaction is fostered by the effects of light, supply of atmospheric oxygen, storage temperature and content of metal ions from cultivation and processing.
The peroxide value is a quality characteristic for determining the freshness or the age of oils. The lower the number, the fresher the oil. The peroxide figure of crude pressed oils lies between 5 and 20, and between 0 and 1 with refined oils.
Protein is one of the basic elements of all life. Together with fats and carbohydrates it makes up the largest usable proportion of food. Whereas it is possible to miss out on fats in a diet, the body depends on a constant supply of protein, as it cannot synthesise it itself.
Its components, amino acids, which are used in the body to produce the body's own proteins, are vital for life. That is why the consumption of protein does not depend on the quantity, but also on the type of composition of the proteins (biological value). A distinction is made between protein from animal foodstuffs (meat, fish, eggs and dairy products) and protein from plant and vegetable foods (cereals, potatoes, nuts and pulses).
• Lecithins are removed with water (degumming).
• Brine is used to remove free fatty acids (neutralisation).
• Bleaching clay is used to remove metal traces and natural dyes (bleaching).
• Water vapour is used to remove oxidation products, natural bitter substances, flavouring and micro-organisms.
Read more about oil production here.
The refractive index is a physical variable, which is both temperature and material dependent. As the speed of light is impacted differently by each substance, every transparent material has its distinctive refractive index. For example, in a material with a refractive index of 1.5 = 3/2, the light has 2/3 of the speed of light in vacuum, that is approx. 200,000 km/sec.
The fat or oil is placed on the prism of a refractometer for analysis. After a 2-minute long period of temperature adjustment to the defined temperature, the refraction (caused by the change of the speed of light) is determined and converted to the refractive index. The refractive index can be used to quickly and easily perform a type test and purity test.
The deviation with fats and oils is 0.00037 per °C.
The saponification value (SV) is a measure of the bound and free acids present in a fat. It indicates the quantity of milligrams of potassium hydroxide needed to saponify 1 g of fat or oil. The lower the mean molar mass of a fat, the higher the saponification value.
Fats with lower fatty acids, like coconut or palm kernel fat, have high saponification values of approximately 250. The majority of vegetable oils have a saponification value of approx. 190.
Fat is more or less solid or liquid depending on the temperature. Accordingly, the Solid Fat Content (SFC) indicates the percentage of the solid parts of fats, based on certain temperatures.
Fats, which have low to medium solidity within a wide temperature range – for instance between a refrigerator temperature of 4°C and a room temperature of 25°C, are called for in spreads in tubes. This guarantees that the spread can be pressed out and spread by consumers over as wide a temperature range as possible. In contrast, fats with a high level of solidity are used within a narrow temperature range – for instance between hand temperature of 30°C and room temperature of 36°C – for the chocolate coating of chocolates. This chocolate coating does not leave any traces of melted chocolate on your hands, whereas it melts as quickly as possible in the mouth ("Melts in the mouth, not in the hand").
The total germ count (aerobic, mesophilic total germs) indicates how many aerobic (oxygen-loving), mesophilic (heat-loving) micro-organisms (bacteria, yeast and fungus) form on an agar bed standardised for microbiological analysis over 72 hours at a regulated incubation temperature of 30°C.
The total germ count, or germ count, also contains desirable micro-organisms, such as lactic acid bacteria in fermented foods, like yoghurt or cheese, as well as undesirable carcinogenic (pathogenic) germs. The hygiene status of foods, like yoghurt and cheese, can be determined by means of the aerobic and mesophilic germs (contamination germs).
A high total germ count is a clear sign of the poor microbial quality of an unfermented food, however further analysis is needed for a precise analysis.
The reverse conclusion is not possible, however, as a low total germ count does not necessarily mean that a foodstuff is perfect, as further indicator germs have to be determined for this.
Transesterification is a process for the targeted change to the physical (e.g. consistency, melting behaviour) and/or nutritional and psychological properties (fatty acid composition) of fats.
The fatty acids per se remain unaltered. Only an intra- and inter-molecular exchange of fatty acids takes place within the fat molecules.
There is a statistical redistribution of fatty acids within the fat molecule with what is known as single-phase transesterification. This produces fats with a different fatty acid composition from a mixture of tristearin (StStSt) and triolein (OOO).
Trans-fatty acids are unsaturated fatty acids with a special spatial structure.
Oils and fats consist of different saturated and/or unsaturated fatty acids. Trans-fatty acids are present in hardened oils/fats, as trans-fatty acids (up to approx. 50%) are produced as an intermediate stage in the hardening of unsaturated fatty acids. Moreover, they also occur in the fat of ruminants, as trans-fatty acids are produced (up to approx. 5%) during microbial hydrogenation in the rumen of these animals. They also occur in refined oils/fats, as trans-fatty acids (1-2%) are produced at high deodorisation temperatures.
Tocopherol (Vitamin E) is the name given to a group of vitamins soluble in fat, which have an anti-oxidative effect.
It is therefore capable of protecting polyunsaturated fatty acids from oxidation. Free radicals would attach and destroy the double bonds of fatty acids. Tocopherol acts as a radical scavenger and eliminates free radicals.
An ideal combination of as few polyunsaturated fatty acids and a high percentage of vitamin E is important for the stability and ability of an oil to be heated. Vitamin E is an essential substance, which the human body cannot produce itself. Correspondingly, it has to be absorbed through food (vegetable oil, nuts, seeds, milk, eggs and certain types of vegetables).