China is the first superpower cotton production country in the world, cotton annual production is 600-700 million ton, it reaches 6.73 million ton in July, 2006, cottonseed annual output is 960-11 00 million ton, it reaches 11 million ton in July, 2006. Cottonseed contains 50-55% cottonseed kernel, and the 30 ~ 35% is oil in cottonseed kernels, 35 ~ 45% protein contains in cottonseed kernels.
Cottonseed is not only a good oil resource, but also is a kind of the main protein resource to be develop and use. Composition of cottonseed protein amino acid is balance, close to the ideal model. However, due to the existence of the gossypol, cottonseed meal content is restricted in the feed additives, moreover as a fertilizer fields.
1. Gossypol and Its Features
Gossypol is a kind of peculiar non-ferrous toxic substances to cottonseed, which accounts for 0.7 ~ 4.8% of the cottonseeds. It concentrates in cottonseed glands, gossypol gland content at 20.6 ~ 39%, it is a kind of crystallized ginger, slightly acidic, its melting point is 181 ~ 185 ℃.
It is soluble in methanol, ethanol, isopropanol, acetone, ether, carbon tetrachloride and other organic solvent, and can not dissolve in oils and fats, insoluble in petroleum and water.
2. Cottonseed Processing Technology
Liquid - liquid - solid method, also known as "liquid - liquid - solid phase extraction method", it is based on the solvent extraction method, the principle of "similar miscibility, cottonseed oil extraction first, gossypol extraction later. It can give full play to the 6 # solvent oil extraction performance, and make the effect of methanol extraction gossypol reach the best state.
The method use clean cottonseed, after shell and kernel separation, it has to go to the special equipment to lower shell content in the kernel, after a series of low temperature tempering process, then goes into leacher for cottonseed oil leaching. Wet meal directly goes into multistage dephenolizing leaching equipment, by removing phenol solvent for removing phenol treatment. After removing phenol by mechanical exsolution and drying in low temperature desolventizing, you can get cottonseed protein products without gossypol. Leaching of cottonseed oil miscella goes into classification of evaporation after filter, stripping to get crude oil, and send to refining plant.
3. New Technology Process Characteristics
- The entire leaching process adopts low-temperature, the maximum to avoid protein denaturation and destruction, and ensure the cottonseed protein nutritional potency of the product.
- Using two kinds of solvent extracting cottonseed oil and removing gossypol step by step, ensure the oil extraction and removing phenol quickly and thoroughly.
- Special multi-stage removing phenol extraction equipment, using the appropriate concentration and temperature of removing phenol solvent extracted rapidly in a short time, avoid degeneration gossypol, combined with the gossypol and other forms of the generation of gossypol derivatives. Free gossypol content in the product is less than 400 mg/kg, lower than the world health organization, the United Nations food and agriculture organization, international organizations such as the United Nations children's fund (UNICEF) recommend by the free gossypol content in food is not more than 600 mg/kg of standard.
- Through the interaction of solvent and water, remove the cottonseed sugar, tannins, phytic acid, aflatoxin and poisonous and harmful material such as pesticide residues, and remove phenol at the same time, which effective protect nutritional ingredients in the cottonseed protein.
- The dedicated oil extractor, high extraction efficiency, saves equipment investment. Wet meal desolventizing process will not proceed, instead of extraction phenol directly, which avoids the thermal denaturation of protein, reduces the energy consumption.
- Low temperature process make the pigment will not be solidified into the material and product, pigment content in crude oil is low, fully guarantee the product quality.