In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, from 4 to 28. Fatty acids are a major component of the lipids in some species such as microalgae but in some other organisms are not found in their standalone form, but instead exist as three main classes of esters: triglycerides, phospholipids, and cholesteryl esters. In any of these forms, fatty acids are both important dietary sources of fuel for animals and important structural components for cells.
In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food.
Margarine is a spread used for flavoring, baking, and cooking. It is most often used as a substitute for butter. Although originally made from animal fats, most margarine consumed today is made from vegetable oil. The spread was originally named oleomargarine from Latin for oleum and Greek margarite. The name was later shortened to margarine.
Rancidification is the process of complete or incomplete autoxidation or hydrolysis of fats and oils when exposed to air, light, moisture, or bacterial action, producing short-chain aldehydes, ketones and free fatty acids.
Coconut oil is an edible oil derived from the kernels, meat, and milk of the coconut palm fruit. Coconut oil is a white solid fat below around 25 °C (77 °F), and a clear thin liquid oil in warmer climates. Unrefined varieties have a distinct coconut aroma. It is used as a food oil, and in industrial applications for cosmetics and detergent production. Due to its high levels of saturated fat, numerous health authorities recommend limiting its consumption as a food.
A saturated fat is a type of fat in which the fatty acid chains have all single bonds. A fat known as a glyceride is made of two kinds of smaller molecules: a short glycerol backbone and fatty acids that each contain a long linear or branched chain of carbon (C) atoms. Along the chain, some carbon atoms are linked by single bonds (-C-C-) and others are linked by double bonds (-C=C-). A double bond along the carbon chain can react with a pair of hydrogen atoms to change into a single -C-C- bond, with each H atom now bonded to one of the two C atoms. Glyceride fats without any carbon chain double bonds are called saturated because they are "saturated with" hydrogen atoms, having no double bonds available to react with more hydrogen.
Saponification is a process of converting esters into soaps and alcohols by the action of aqueous alkali. Soaps are salts of fatty acids, which in turn are carboxylic acids with long carbon chains. Sodium stearate is a typical soap.
Palmitic acid is a fatty acid with a 16-carbon chain. It is the most common saturated fatty acid found in animals, plants and microorganisms. Its chemical formula is CH3(CH2)14COOH, and its C:D is 16:0. It is a major component of the oil from the fruit of oil palms, making up to 44% of total fats. Meats, cheeses, butter, and other dairy products also contain palmitic acid, amounting to 50–60% of total fats. Palmitates are the salts and esters of palmitic acid. The palmitate anion is the observed form of palmitic acid at physiologic pH (7.4).
Saponification value or saponification number represents the number of milligrams of potassium hydroxide (KOH) or sodium hydroxide (NaOH) required to saponify one gram of fat under the conditions specified. It is a measure of the average molecular weight of all the fatty acids present in the sample in form of triglycerides. The higher the saponification value, the lower the fatty acids average length, the lighter the mean molecular weight of triglycerides and vice versa. Practically, fats or oils with high saponification value are more suitable for soap making.
Lauric acid, systematically dodecanoic acid, is a saturated fatty acid with a 12-carbon atom chain, thus having many properties of medium-chain fatty acids. It is a bright white, powdery solid with a faint odor of bay oil or soap. The salts and esters of lauric acid are known as laurates.
In chemistry, the iodine value is the mass of iodine in grams that is consumed by 100 grams of a chemical substance. Iodine numbers are often used to determine the degree of unsaturation in fats, oils and waxes. In fatty acids, unsaturation occurs mainly as double bonds which are very reactive towards halogens, the iodine in this case. Thus, the higher the iodine value, the more unsaturations are present in the fat. It can be seen from the table that coconut oil is very saturated, which means it is good for making soap. On the other hand, linseed oil is highly unsaturated, which makes it a drying oil, well suited for making oil paints.
In chemistry, acid value is a number used to quantify the acidity of a given chemical substance. It is the quantity of base, expressed as milligrams of KOH required to neutralize the acidic constituents in 1 gram of a sample.
The smoke point, also referred to as the burning point, is the temperature at which an oil or fat begins to produce a continuous bluish smoke that becomes clearly visible, dependent upon specific and defined conditions. Smoke point values can vary greatly, depending on factors such as the volume of oil utilized, the size of the container, the presence of air currents, the type and source of light as well as the quality of the oil and its acidity content, otherwise known as free fatty acid (FFA) content. The more FFA an oil contains, the quicker it will break down and start smoking. The lower the value of FFA, the higher the smoke point. However, the FFA content typically represents less than 1% of the total oil and consequently renders smoke point a poor indicator of the capacity of a fat or oil to withstand heat.
Soybean oil is a vegetable oil extracted from the seeds of the soybean. It is one of the most widely consumed cooking oils and the second most consumed vegetable oil. As a drying oil, processed soybean oil is also used as a base for printing inks and oil paints.
The Polenske value is a value determined when examining fat. It is an indicator of how much volatile fatty acid can be extracted from fat through saponification. It is equal to the number of milliliters of 0.1 normal alkali solution necessary for the neutralization of the water-insoluble volatile fatty acids distilled and filtered from 5 grams of a given saponified fat. It is measure of the steam volatile and water insoluble fatty acids, chiefly caprylic, capric and lauric acids, present in oil and fat. The value is named for the chemist who developed it, Eduard Polenske.
The Kirschner value or Kirschner number is a value determined when examining fat. The Kirschner value is an indicator of how much volatile fatty acid can be extracted from fat through saponification. It consists of the number of milliliters of 0.1 normal sodium hydroxide necessary for the neutralization of water-soluble silver salts made from the water-soluble volatile fatty acids distilled from 5 grams of a given fat.
In chemistry, the terms volatile acid and volatile acidity (VA) are used somewhat differently in various application areas.
In analytical chemistry, the hydroxyl value is defined as the number of milligrams of potassium hydroxide (KOH) required to neutralize the acetic acid taken up on acetylation of one gram of a chemical substance that contains free hydroxyl groups. The analytical method used to determine hydroxyl value traditionally involves acetylation of the free hydroxyl groups of the substance with acetic anhydride in pyridine solvent. After completion of the reaction, water is added, and the remaining unreacted acetic anhydride is converted to acetic acid and measured by titration with potassium hydroxide.
Saltwater soap, also called sailors' soap, is a potassium-based soap for use with seawater. Inexpensive common commercial soap will not lather or dissolve in seawater due to high levels of sodium chloride in the water. Similarly, common soap does not work as well as potassium-based soap in hard water where calcium replaces the sodium, making residual insoluble "scum" due to the insolubility of the soap residue. To be an effective cleaning agent, soap must be able to dissolve in water.
Trans fat, also called trans-unsaturated fatty acids, or trans fatty acids, is a type of unsaturated fat that occurs in foods. Trace concentrations of trans fats occur naturally, but large amounts are found in some processed foods. Since consumption of trans fats is unhealthy, artificial trans fats are highly regulated or banned in many nations. However, they are still widely consumed in developing nations, resulting in hundreds of thousands of deaths each year. Serious interest has been given to determining their sources, to better avoid them.
