Decolorization is a process to improve the color of edible oil during the processing of edible oil. It can remove pigments and other impurities in the oil and is an important process for reviewing and testing high-grade edible oil. The effect of decolorization is closely related to the processing parameters. The processing parameters have a significant impact on the color of the oil, mainly including the following aspects:
Temperature: In the process of oil processing, temperature is one of the key factors affecting the color. At different processing stages, temperature control has a direct impact on the color of the oil. Under high temperature conditions, the oil is more likely to undergo oxidation reactions, resulting in a darker color. For example, during the steaming and frying process, if the temperature is too high or the time is too long, the phospholipid content of the oil will increase, and the color of the oil will also deepen.
Time: Time control of each section in the production process is also one of the important factors affecting the color of the oil. Taking the steaming and frying sections and the decolorization section as examples, long-term high-temperature treatment will cause excessive oxidation and pyrolysis of the oil, generating more pigment substances, such as aldehydes, ketones, etc. The presence of these substances makes the oil appear darker. In the decolorization process, if the decolorizer is in contact with the oil for too long, the quality of the oil will deteriorate, including the recovery of the oil color and the increase of the acid value.
Pressure: In production, the size of the pressing pressure will also affect the color of the oil. High pressure may promote the release of pigment substances in the oil. Under different pressure conditions, the chemical reaction rate and type of the oil may be different. Although it is not as intuitive as temperature and time, it will also affect the color of the product.
Type and dosage of decolorizer: The decolorization effect of the decolorizer affects the color of the oil. There are many types of oil decolorizers, the most common ones are activated carbon, activated white clay, diatomaceous earth, talcum powder, etc. Different decolorizers have different effects on oil improvement. In addition, the amount of decolorizer is proportional to the improvement of the color of the oil. Excessive use will cause the color of the oil to be too light, and even produce odor. Small amount will affect the decolorization effect and the color of the oil will be dark. Therefore, it is necessary to select a suitable decolorizer and determine the appropriate dosage.
