In common, rapeseed oil is canola oil, also called coriander oil, which uses a cruciferous plant canola (rapeseed) seed to press out transparent or translucent liquids. Rapeseed oil is golden yellow or brownish yellow and has certain stimulating smell, known as “green smell” in the folk. This smell contains a certain amount of mustard glucoside, but the excellent rapeseed does not contain this substance. Rapeseed oil is the one of the main oil in China, mainly produced in Yangtze river basin and the southwest and northwest. The production is the first in the world.
Rapeseed oil nutritional analysis:
1.The absorption rate of human body on rapeseed oil is very high, which can reach 99%. Therefore its linoleic acid and other unsaturated fatty acids and vitamin E and other nutritional ingredients can be absorbed by the body, which have certain soften blood vessels and anti-aging effect.
2.Because the raw material is oil plant species, usually contains a certain seeds of phospholipids, which is very important to the growth of the blood vessels, nerves and brain.
3.Rapeseed oil contains little or no cholesterol, so the people control cholesterol intake can be at ease to eat. In terms of nutrition, the digestion and absorption rate of body on rapeseed oil can be as high as 99%, which is favorable to the gallbladder function. When the liver is in pathological conditions, rapeseed oil can also be normally metabolized by human body.
Rapeseed oil refining compete through 3 steps: semi-continuous degumming process, continuous decoloring process and continuous deodorization process.
Rapeseed salad oil refining process (intermittence):
Alkali lye rich oil soapstock—→salt out —→lean oil soapstock
Filter crude rapeseed oil—→preheat—→neutralize—→steady depositing—→separate—→washing←—softening water
Filter←—distillation deodorization←—filter←—adsorption decoloration←—dehydration
↓ ↓ ↓ ↑ ↓
Refined rapeseed oil steam waste clay adsorbent waste water
Alkali refining operation temperature -- initial temperature is 30 ~ 35 ℃; final temperature is 60 ~ 65 ℃; lye concentration is 16°Bé; excessive alkali content is 0.2% ~ 0.25% of oil; plus sodium is 0.5% of the oil (concentration is 40 ° Be); neutralization time is about l hour; sedimentation separation time is not less than 6 hours. Alkali refining washing temperature is 85 ~ 90 ℃, and the first washing water is dilute salt water (lye concentration: 0.4%, 0.4% of the salt), additive amount is 15% of the oil. Then use hot water washing several times, washing to alkali refining soap content is not more than 50 PPM. When oil decoloring
, first vacuum dewatering is 30 min, and temperature is 90 ℃, and operating absolute pressure is 4.0 kPa. Then add activated clay to decolorize, and clay content is 2.5% ~ 3% of oil, decoloring temperature is 90～95℃. Decolorization time is 20 min, then cool to 70 ℃ and filter. Decoloring oil is absorbed by vacuum into deodorization tank formed by first, secondary steam jet pump to heater to 100 ℃. And then open the third and the fourth steam jet pump and atmospheric condenser cooling water. The deodorization temperature is not lower than 245 ℃. Operating absolute pressure is 260 ~ 650 pa; atmospheric condenser water temperature control about 30 ℃; the stripping steam pressure is 0.2MPa; directly into the capacity of 8 ~ 16 kg/t, h; deodorization time is 3 ~ 6 h. Finish deodorization and then cool to 70 ℃ and then filter.
Rapeseed salad oil refining process (completely continuous)
Phosphoric acid Alkali lye
Filter crude rapeseed oil—→preheat—→mix—→oil alkali match—→mixed reaction—→de-soapstock—→soapstock
Filter←—distillation deodorization←—filter←—adsorption decoloration←—dryer←—dehydration←—wash←—soften
↓ ↓ ↓ ↑ ↓
Rapeseed salad oil steam waste clay adsorbent waste water
Filter oil’s impurity is not more than 0.2%; lye concentration is 18 ~ 22 °Be ; excessive alkali content is 10% ~ 25% of normal alkali quantity. Sometimes first add 0.05% ~ 0.05% of phosphoric acid (concentration is 85%); taking off the soapstock temperature is 70 ~ 82 ℃; washing temperature is about 95 ℃; soft water adding amount is 10% ~ 20% of oil. Continuous vacuum drying dehydration -- the temperature is 90 ~ 95 ℃ and operating absolute pressure is 2.5 ~ 4.0 kPa. Adsorption bleaching temperature is 105 ~ 100 ℃, and the operation absolute pressure is 2.5 ~ 4.0 kPa. The time for decoloring operating is about 30 min; activated clay content is 1% ~ 4% of oil. When use vertical leaf filter to separator clay, the filter temperature is not lower than 100 ℃. In decolorizing oil: P≤5 PPM, Fe≤0.1 PPM, Cu≤0.01 PPM. Deodorization temperature is about 240 ~ 260 ℃; operating absolute pressure is 260 ~ 650 pa, stripping steam intake is 0.5% ~ 2%; deodorization time is 40 ~ 120 min; citric acid (concentration is 5%) is 0.02% ~ 0.04% of oil; security filtering temperature is not higher than 70 ℃.