The wax in edible oil is mainly formed by the reaction of higher fatty alcohols and higher fatty acids, in addition to some higher free fatty alcohols, fatty acids and hydrocarbons. At higher temperatures, wax exists in the form of molecules in the oil. When the temperature drops to a certain value, crystals will precipitate in the oil, causing the edible oil to become turbid, affecting its taste and transparency. In addition, wax is generally stable and difficult to decompose, and it is difficult for the human body to absorb it. Therefore, in recent years, in the application of edible oil, winterization can be used to dewax edible oil, such as lard, chicken oil, fish oil and other aquatic animal and vegetable oils, rice bran oil, palm oil, cottonseed oil, tea seed oil, and corn. Oil, sesame oil and sunflower oil, etc., make it a high-grade edible oil.
Rice bran oil has a high solid fat content, which contains 1%-3.8% stearic acid and 12%-18% palmitic acid. The solid fat crystallizes at low temperature, the fat becomes muddy, and solid-liquid stratification occurs.
After the rice bran oil is physically refined, the acid value KOH is 1-3 mg/g, cooled to 30°C, pumped into the crystallization tank, slowly and uniformly cooled to 0-2°C after 24 hours, and kept for 48 hours. Slow stirring is used during crystal growth. During the process of crystal growth, allow the temperature to rise slightly by 2-5℃, and then filter with a filter pre-coated with diatomaceous earth. The filter pressure of the pre-coating is about 0.06MPa, the filter temperature is set at 25 ℃, Use the difference of oil level and gravity to filter naturally, avoid using shearing and stirring action and use a strong oil pump to filter under pressure, which is easy to break the fat crystal. Physically refined rice bran oil is dewaxed and degreased to obtain about 90% of liquid oil and 5%-10% of solid fat (with a small amount of liquid oil).
The other method is two crystallization filtration, cooling the deodorized rice bran oil to about 30℃, cooling and crystallization for 24h, filtering once, the filter pressure is less than or equal to 0.35MPa, the filtered oil enters the second crystallization tank, and the oil temperature is less than or equal to 25 ℃, cultivate crystals for 24 hours, perform secondary filtration, and filter pressure is less than or equal to 0.35MPa.
For rice bran oil leaching, refining and winterization and dewaxing projects, Zhengzhou Dingsheng Machinery Manufacturing Co., Ltd. has rich engineering experience, and there are many project cases of rice bran oil making production line at home and abroad. We look forward to more domestic and foreign customers to visit Zhengzhou Dingsheng Machinery Manufacturing Co., Ltd. and discuss cooperation.
