Glycerol is a natural part of triglycerides, the main components of fats and oils. In soap - making (saponification), triglycerides react with alkalis, splitting into soap and glycerol. In biodiesel production, when vegetable oils or animal fats react with alcohol, glycerol is generated as a by - product. The growth of the biodiesel industry has made this a significant source of glycerol.

In living organisms, glycerol is produced during the breakdown of body fat in adipose tissue to release fatty acids for energy. Some microbes, such as yeast during fermentation, also produce glycerol as a by - product.

Glycerol is widely used as a humectant in the food industry. It helps keep baked goods like bread, cakes, and cookies moist, thus extending their shelf - life and maintaining a soft texture.

With a sweet taste and fewer calories than sugar, glycerol serves as a sugar substitute in low - calorie and sugar - free foods, such as chewing gum, where it also helps maintain the gum's softness.

In certain food products, glycerol acts as an emulsifier, keeping oil and water - based ingredients evenly dispersed, as seen in salad dressings and some dairy products.

In pharmaceuticals, glycerol is a common excipient. It can dissolve active ingredients in liquid medications, like cough syrups, and provides a smooth, palatable texture.

Its lubricating properties make glycerol useful in suppositories and enemas, facilitating their insertion into the body.

Glycerol is often included in wound - healing products. By keeping the wound area moist, it promotes the healing process and may reduce scarring.

In skincare products such as moisturizers, lotions, and creams, glycerol is a key humectant. It draws moisture from the air and the skin's deeper layers to the surface, hydrating the skin and preventing dryness and premature aging.

In haircare products like shampoos, conditioners, and hair serums, glycerol smooths the hair cuticle, reduces frizz, and keeps the hair moisturized, making it more manageable.

In toothpaste, glycerol gives the paste a smooth, spreadable consistency and prevents it from drying out. In soaps, it adds a moisturizing effect.

Glycerol's excellent heat - transfer properties and ability to maintain viscosity over a wide temperature range make it suitable as a coolant in some industrial processes, like in certain engines and machinery. It also acts as a lubricant, reducing friction between moving parts.

Glycerol is used in the production of plastics and polymers to enhance their flexibility, durability, and processability. For example, in the production of polyurethanes, glycerol serves as a building block.

Glycerol can be converted into nitroglycerin, a key component in explosives like dynamite. Due to nitroglycerin's instability, it is often absorbed onto an inert material for safe handling. Glycerol - based compounds are also used in some rocket propellants.