We usually hear about the use of Glycerin . Below we will tell you what it is, what it is for and what its risks are, among other information of great importance.
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Glycerol – what is it
Glycerol also called glycerin; it is a simple polyol compound. It is a colorless, odorless and viscous liquid, with a sweet and non-toxic taste. The glycerol backbone is found in all lipids known as triglycerides. It is widely used in the food industry as a sweetener and humectant and in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature.
Glycerol – structure
Although achiral, glycerol is prochiral with respect to the reactions of one of the two primary alcohols. Therefore, in substituted derivatives, the stereospecific numbering labels each carbon as sn-1, sn-2, or sn-3.
Glycerol – how it is produced
Glycerol is generally obtained from plant and animal sources where it occurs as triglycerides. Triglycerides are glycerol esters with long chain carboxylic acids. Hydrolysis, saponification or transesterification of these triglycerides produces glycerol and the fatty acid derivative:
Triglycerides are treated with an alcohol such as catalytic based ethanol to give ethyl esters of fatty acids and glycerol:
Typical plant sources include soybeans or palm. Animal derived tallow is another source. Approximately 950,000 tons per year are produced in the United States and Europe; 350,000 tons of glycerol were produced per year in the United States alone from 2000 to 2004.
What is synthetic Glycerol like?
Although generally not cost effective, glycerol can be produced by various routes from propylene. The epichlorohydrin process is the most important; It involves the chlorination of propylene to give allyl chloride, which is oxidized with hypochlorite to dichlorohydrins, which reacts with a strong base to give epichlorohydrin. This epichlorohydrin is hydrolyzed to glycerol. Chlorine-free processes for propylene include the synthesis of glycerol from acrolein and propylene oxide.
Due to the large-scale production of biodiesel from fats, where glycerol is a waste product, the glycerol market is depressed. Therefore, synthetic processes are not economical. Due to oversupply, efforts are underway to convert glycerol into synthetic precursors, such as acrolein and epichlorohydrin.
Glycerol – what is it for
Food industry
In foods and beverages, glycerol serves as a humectant, solvent, and sweetener, and can help preserve food. It is also used as a filler in commercially prepared low-fat foods (eg, Cookies) and as a thickening agent in liqueurs. Glycerol and water are used to preserve certain types of plant leaves. As a substitute for sugar, it has about 27 kilocalories per teaspoon (sugar has 20) and is 60% sweeter than sucrose.
As used in food, the Academy of Nutrition and Dietetics classifies glycerol as a carbohydrate. The United States Food and Drug Administration (FDA) carbohydrate designation includes all caloric macronutrients, excluding protein and fat. Glycerol has a similar caloric density to table sugar, but a lower glycemic index and a different metabolic pathway within the body, which is why some diet proponents accept glycerol as a sweetener compatible with low-carb diets.
Pharmaceutical and personal care applications
Glycerol is used in medical, pharmaceutical, and personal care preparations, primarily as a means of improving smoothness, providing lubrication, and as a humectant. It is found in allergenic immunotherapies, cough syrups, elixirs and expectorants, toothpaste, mouthwashes, skin care products, shaving cream, hair care products, soaps and water-based personal lubricants.
Glycerol is a component of glycerin soap. Essential oils are added for fragrance. This type of soap is used by people with sensitive, easily irritable skin, as it prevents dry skin with its moisturizing properties. It draws moisture through the layers of the skin and slows or prevents excessive drying and evaporation.
Glycerol can be used as a laxative when introduced into the rectum as a suppository or as a small volume (2-10 ml) (enema); irritates the anal mucosa and induces a hyperosmotic effect.
Taken orally (often mixed with fruit juice to reduce its sweet taste), glycerol can cause a rapid and temporary decrease in internal eye pressure.
Botanical extracts
When used in “tincture” method extracts, specifically as a 10% solution, glycerol prevents tannins from precipitating in plant ethanol extracts (tinctures). It is also used as an “alcohol-free” alternative to ethanol as a solvent in the preparation of herbal extracts. It is less extractive when used in a standard dyeing methodology. Alcohol-based tinctures can also remove alcohol and replace it with glycerol for its preservative properties. These products are not “alcohol-free” in a scientific sense, as glycerol contains three hydroxyl groups. Fluid extract manufacturers often extract herbs in hot water before adding glycerol to make glycerites.
When used as a “true” primary alcohol-free botanical extraction solvent in non-dye-based methodologies, glycerol has been shown to possess a high degree of extractive versatility for botanists, including the removal of numerous complex constituents and compounds, with a Extraction power that can rival alcohol and water-alcohol solutions.
Liquid Electronic Cigarette
A bottle of flavored “e-liquid” for “vaping” lists glycerin as one of the ingredients.
Glycerin, along with propylene glycol, is a common component of e-liquid, a solution used with electronic vaporizers (electronic cigarettes). This glycerol is heated with an atomizer (a heating coil often made from Kanthal wire), producing the aerosol that delivers nicotine to the user.
Antifreeze
Like ethylene glycol and propylene glycol, glycerol is a nonionic kosmotrope that forms strong hydrogen bonds with water molecules, competing with water-water hydrogen bonds. This interaction disrupts ice formation. The minimum freezing point temperature is approximately -36 ° F (-38 ° C) corresponding to 70% glycerol in water.
Glycerol was historically used as an antifreeze for automotive applications before being replaced by ethylene glycol, which has a lower freezing point. While the minimum freezing point of a glycerol-water mixture is higher than an ethylene glycol-water mixture, glycerol is non-toxic and is being retested for use in automotive applications.
Glycerol – problems
On May 4, 2007, the US Food and Drug Administration advised all US drug manufacturers to test all batches of glycerol for toxic diethylene glycol. This followed the occurrence of hundreds of fatal poisonings in Panama as a result of a falsified import customs declaration by the Panamanian import / export firm Aduanas Javier de Gracia Express, SA The cheapest diethylene glycol was labeled the most expensive glycerol.
Dr. Samantha Robson ( CRN: 0510146-5) is a nutritionist and website content reviewer related to her area of expertise. With a postgraduate degree in Nutrition from The University of Arizona, she is a specialist in Sports Nutrition from Oxford University and is also a member of the International Society of Sports Nutrition.
