Glycerin, better known in biochemistry as glycerol, is the propanetriol formula C3H8ANY3a polyol that is present in all fats and oils, both vegetable and animal, and is part of many lipids, eg triglycerides and phospholipids. Obtaining high purity glycerin uses vegetable sources, mainly palm oil, which is why it is often referred to as vegetable glycerin, being a product widely used in several industrial sectors, notably in the food and pharmaceutical industries.
The glycerin molecule is composed of a chain of three carbon atoms, each attached to a hydroxyl group (-OH or alcohol group). The hydroxyl groups make the glycerin hydrophilic and dissolve in water and also form hydrogen bonds, making the glycerin highly viscous. Solidifies at 18°C. Although from a chemical point of view glycerin is an alcohol, from a nutritional point of view it is classified as a carbohydrate.
Production of glycerin in industry
The vast majority of glycerin is produced as a by-product of the soap industry (in the saponification reaction) and biodiesel production (in the transesterification reaction). In both cases, both animal and plant lipids can be used, although mostly vegetables are used in the production of biodiesel.
Vegetable glycerin is also made directly from vegetable oils, mainly palm and coconut oil. The process consists of mixing the oil with water and applying high temperature and pressure. Under these conditions, glycerin separates from fatty acids and dissolves in water. The aqueous and oily phase are separated by decantation and the glycerin is isolated and purified from the aqueous fraction by distillation.
Glycerin approved for food use must be greater than 99% pure. Currently obtained only through processes of direct obtaining from vegetable oils. The obtained as a by-product in the manufacture of biodiesel and soap is of low quality, low purity and may also contain toxic substances used during the industrial process. The purification of these by-products is economically much more expensive than direct production, so they are usually discarded or used for research, something that has become increasingly frequent due to the increase in research that requires this substance, even if it is not of high purity.
High purity glycerin, produced from plant-based raw materials, is mainly used in the food, cosmetic and pharmaceutical industries, although it is also used in many other sectors.
In the food industry it is used for two main reasons:It tastes sweet but provides fewer calories than sugar, like saccharin and other polyalcohols. In addition, glycerol is not cariogenic and is digested more slowly than sucrose (table sugar). does not have a high impact on the glycemic index. Many foods marked “low carb” often contain glycerol as a sweetener. Glycerin is very hygroscopic and absorbs a lot of moisture from the air, so it is used as a wetting agent. For example, it helps keep baked goods soft longer.
The hygroscopic ability of glycerol is also used in cosmetics and is a common ingredient in moisturizing creams, lotions and soaps. In the pharmaceutical industry, glycerin is one of the most used excipients. o plant extracts they can use glycerin as a solvent and avoid the use of alcohol, important for people who cannot or do not want to consume alcohol. Glycerin is also used as an active ingredient for various medical purposes, for example it is used as a laxative or to treat psoriasis, ulcers, burns and other skin problems.
Vegetable glycerin and deforestation
Many environmental groups around the world have long drawn attention to the effects of massively cultivating palm trees to obtain their oil, the main raw material for the production of vegetable glycerin. In addition to the large volume of vegetable glycerin consumed, palm oil itself is another of the most used additives in the food industry.
In Southeast Asia are the most deforested areas to create large monoculture spaces dedicated to palm. Indonesia, Malaysia and Papua New Guinea account for approximately 85% of the world’s palm cultivation. Some of its most worrisome effects are destruction of the Sumatran orangutan’s natural habitat (I put abelii). This primate, a very close relative of the human species and one of only two orangutan species in existence, is in critical condition according to the International Union for Conservation of Nature’s Red List.
In 2004, the Roundtable on Sustainable Palm Oil (RSPO) was formed, an international organization whose objective is to promote the sustainable cultivation and use of palm oil. Among its tools, a sustainable production certification system stands out, which is recognized in more and more countries.