Half Drying oils experiment

Semi-Drying Oils Test
Semi-Drying Oils Test

Pure oils contain carbon, hydrogen and oxygen. These compounds are insoluble in water but soluble in many organic solvents. Oils can be classified in many ways. The best known classifications in the food industry are made in the form of fats and oils, or in the form of animal and vegetable oils.

Fats contain a significant amount of esters of saturated acids with glycerin. These fats, which are solid or semi-solid, are mostly animal fats. Liquid oils contain esters which are formed by unsaturated fatty acids with glycerin. These oils are mostly vegetable oils such as olive oil, cottonseed oil or soybean oil.

Oils are in three groups according to their degree of unsaturation and drying characteristics:

  • Non-drying oils are those with a low iodine index (below about 90).
  • Semi-drying oils are those with an iodine index of approximately 90-130.
  • Dried fats are oils with an iodine index above 130.

Dried oils solidify outdoors. Double bonds in their structures react with oxygen in the air and allow the oil to solidify. However, drying of the oil does not mean that it evaporates away from the environment. Linseed oil, walnut oil, hemp seed oil, poppy oil, hemp oil, safflower oil, castor oil and Chinese oil are such oils.

Semi-drying oils include soybean oil, cottonseed oil, sunflower oil, safflower oil and mustard oils.

Olive oil, peanut oil, hazelnut oil, cocoa butter, palm oil, fish oil and tree oil are also included in the non-drying oils class.

The higher the level of unsaturation of the oils, the higher the drying properties.

 

Semi-drying oils tests are also performed by authorized laboratories within the scope of chemical food analyzes. In these studies, standards and test methods published by domestic and foreign organizations are followed.