Refractive index is an indicator that shows how slowly the light travels in any material with respect to the light traveling through the void. Mathematically, it is the ratio of the sine of the angle of light to that matter to the sine of the angle of refraction. Various The refractive index of the media is inversely proportional to the speed of light in that medium. That is, if the refractive index is too high, the light moves so slowly.

The refractive index finds an important application area especially in vegetable and animal oils. The values ​​it presents are widely used in the food sector. For example, the unsaturated fatty acids and their esters have a very high refractive index. In contrast, the higher the fatty acid chain length, the lower the refractive index.

When margarine is produced, the unsaturated fatty acids are saturated with hydrogen. During this process, refractive index value is used as follow-up parameter and it is decided whether the operation is completed or not. The refractive index value of the materials varies according to the ambient temperature and the wavelength of the refracted light.

In the laboratories, the refractive index is determined and the analysis is made according to the melting degree for the oils melting at higher temperatures and for the oils that become liquid at 20 degree temperature.

Refractometer is used to measure refractive index of oils. These devices are used to measure the solids content and refractive indices in oils. Refractive index measurements are very important in the analysis of food products such as oil, fruit juice, sugar production, pharmaceuticals and chemical sector.

Analyzes to determine the refractive index of oils are carried out within the scope of physical analyzes in authorized laboratories. The standards used during these analyzes are:

• TS ISO 1739 Butter - Determination of milk fat refractometer index (reference method)
• Animal and vegetable fats and oils - Determination of refractive index TS 4960 EN ISO 6320
• TS 894 Edible vegetable oils - Examination methods