Gossypol Extraction From Methanol Phase Leached Cottonseed Meat By A Two-Liquid Phase Solvent System

In recent ten years, gossypol is of scientific and medical interest because of itsanti-tumor, anti-fertility, and anti-viral properties. High-level cottonseed oil, gossypol-free cottonseed meal and methanol phase abundant in free gossypol (FG) could beobtained by the leaching process with a two-liquid phase solvent (TPS) system. If theFG in methanol phase can be extracted, prepared to gossypol acetic acid and refinedto meet the medicinal criterion, the value of this technology will be greatly improved.This dissertation studied the problems in the process of extracting FG from themethanol phase after TPS treating ground cottonseed meat. The main issues are asfollows:1,The effect of TPS leaching parameters on the FG dissolving quantity in themethanol phaseTPS leaching parameters were studied and the results showed that:(1) When the methanol phase consisted of 95% methanol and 0.1% citric acid,not only the high-level cottonseed oil, gossypol -free cottonseed meal could beobtained, but also benefited gossypol resolving in methanol phase.(2) Water could accelerate the breakage of gossypol gland and release ofgossypol to methanol phase. So a small amount of water in methanol phase couldimprove the gossypol dissolving in methanol phase and reduce the content of boundgossypol (BG) in cottonseed meal. But too much water would cut down the gossypoldissolving in methanol phase. The water content in methanol phase should not exceed10 v%.2,Distribution coefficient of FG in methanol phase and petroleum ether phaseThe distribution coefficients of FG in methanol phase and in petroleum etherphase were determined at different process conditions. Different factors affecting thedistribution coefficient were inspected and an empirical equation was correlated. Theresults of the study showed that:(1) Addition of a small amount of citric acid in methanol phase was benefit to thedissolution of FG in methanol phase.(2) The FG contribution coefficient increased linearly by increasing methanolcontent from 80% to 100% and by increasing leaching temperature from 0℃ to 40℃.(3) An empirical equation for FG distribution coefficient in methanol phase and iDissertation of the master degree of engineering Abstractin petroleum ether phase was correlated. The dependence of FG distributioncoefficient on methanol content in methanol phase and leaching temperature wasestablished. The verification of the empirical equation to experiment results was (4.65±4.63)%.3,The study of FG extraction from methanol phase by water dilution methodGossypol could precipitate from methanol phase when the solution leachingcottonseed meat was diluted with water, according to the character that FG was hardlydissolved in water. The best process condition was obtained and the results of thestudy showed that:(1) The gossypol stability was affected by storage time, temperature and raystrength. During fixed storage time, the loss of FG was less when storage temperaturewas lower and ray strength was weaker. Under fixed storage conditions, the loss ofFG was more when storage time was longer. The better storage condition was in –20℃ without light.(2) The influence of single factor on gossypol yield and purity was investigated.Gossypol yield and purity firstly increased and then dropped with the increasing ofcondensed volume of methanol phase after leaching cottonseed meat, and with theincreasing of solution pH. Good result was obtained at the condensed volume ofmethanol phase 50ml/50g cottonseed meat and pH 5. With the water addition volumeincreasing, the gossypol yield increased and gossypol purity first increased and thendropped. The best volume was 1.7 times of condensed volume. The gossypol yieldincreased when standing time extended to 8h. After 8h, the yield did not change butthe purity dropped. So the best standing time was 8h. With the water additionfrequency increased, the gossypol yield increased and gossypol purity dropped. So thebest water a...