Pure oil is a colorless and odorless liquid in the molten state. It becomes a white waxy solid when solidified. Most natural oils are light yellow to brown and have a certain smell. Various odors are generally caused by non-fermented ingredients. For example, the aroma of coconut oil comes from nonyl ketone, rapeseed oil and mustard oil can produce pungent and odor due to their glucosinolates, and oxidative rancidity can also Produces odor. The color of natural oils is due to the carotenoid substances they contain.
The characteristics of oils, such as color, odor, melting point and freezing point, acid value, saponification value, iodine value, vinegar value, etc., are closely related to the composition and properties of fatty acids. Let’s take you to learn about the refractive index and dielectric constant of oils and fats:
Refractive index: The refractive index is also an important physical constant of oils and fatty acids. Different oils contain different fatty acids. The refractive index is also different. Measuring the refractive index can quickly understand the general composition of oil and grease, and can be used to identify the type and quality of various oils. The refractive index of oil increases with the increase of molecular weight and increases with the increase of double bonds. The presence of conjugated double bonds has a higher refractive index than similar non-conjugated compounds.
Dielectric constant: The dielectric constant is the data of the polarity of the reacting substance molecules. The dielectric constant of most oils and fats is between 3.0-3.2, except castor oil, which contains a large amount of hydroxy acids, so the dielectric constant is 4.6-4.7.
微信扫一扫打赏
