| Jatropha curcas is a kind of tree that has very high economic value, its roots, stems, leaves and fruits all can be used.The oil content of its seed is as high as 60%, in which the ratio of oleic acid and linoleic acid is more than 70%,the content of unsaturated fatty acids are high whereas the iodine value is low. It is a semi-dry oil with good fluidity, which is the ideal raw material for biodiesel. The biodiesel prepared by Jatropha curcas oil can meet the II emission standards of European.The content of protein in Jatropha curcas seed is very rich, which accounts for 27% ~ 32% of seed weight, and the amino acid composition is balanced. However, the presence of Curcin and phorbol ester, the seed cake after oil extraction can not directly feed, it's mainly used as fertilizer.Therefore, using appropriate protein extraction technology to explore the way of removing toxin in Jatropha curcas seeds'protein will help the development and utilization of Jatropha curcas seed cake.In this paper, the following aspects of Jatropha oil and its seed protein were studied:(1) This study began with research on Jatropha curcas seed oil extraction by cold-pressed–solvent extraction, after experiment and analysis, the better conditions were as follows: the pressure 40MPa, time 120min, temperature 65℃, 10% water content. Under the Conditions, the oil extraction was around 41%, while the residual oil in cold pressed cake was about 28%.Using hexane as solvent, under the conditions: the solvent ratio 1.2, temperature 55℃, time 30min, continuous extracting the cold pressed cake 5 times, the final residual oil in Jatropha curcas seeds was as low as 0.8%.(2) After hydration degumming and vacuum dehydration, the acid value of Jatropha curcas seed oil was 15.49 mg KOH/g oil, while the acid value of raw materials for biodiesel preparation using homogeneous base catalyst is required lower than 1.0 mg KOH/g oil, thus there is a need to reduce acid value. This paper studied on the solvent extraction deacidifieing as well as acid-dropping by pre-esterification catalyzed by sulfuric acid. Through single factor experiments and response surface analysis, the optimal solvent deacidifieing process was obtained: alcohol to oil ratio (V/V oil) 2.0:1, water content in Jatropha curcas seed oil 0.08%, extraction temperature 45℃, extracted 5 times for each of 10min.While, as for the method of sulfuric acid pre-esterification deacidifieing, by adding THF as a cosolvent, through single factor experiments and orthogonal analysis, the optimum conditions were obtained as follows: amount of methanol added (V/V oil) 0.85:1, reaction time 45min, reaction temperature 65℃, catalyst loadings (V/V oil) 0.012:1, addition of cosolvent (V/V oil) 0.5:1.(3) In order to select the appropriate solvent that can effectively promote the formation of methanol and Jatropha curcas oil homogeneous, the comparisons of the nature contrast of 8 solvent and the ternary phase diagram that formed by the ether or tetrahydrofuran solvent and Jatropha curcas seed oil, methanol in different temperatures were studied, we finally chosed THF as a cosolvent.(4) In the conditions when the acid value was effectively reduced by sulfuric acid pre- esterification, we used THF as a cosolvent and NaOH as catalyst, studied the biodiesel process of Jatropha curcas seed oil through methyl esterification. By single factor analysis and orthogonal experimental design, when the amount of methanol added (V/V oil)was 0.56:1, reaction time 18min, reaction temperature 65℃, catalyst loadings (w/w oil) 1% addition of cosolvent (V/V oil) 0.5:1 conditions, a higher conversion rate of methyl esterification was obtained.(5) In this paper, alkaline extraction and acid precipitation were employed to extract protein from Jatropha curcas seed meal.After respectively studied the influence of different factors on extraction yield by single factor experiments, and then optimized conditions by orthogonal test, the optimized conditions were obtained as follows: alkaline extraction solid-liquid ratio 1:11, pH 8.5, temperature 55℃, time 100min;acid pH 4.4, temperature 55℃, time 40min.Under the process conditions, the separation yield of Jatropha curcas seed protein was 76.63%, purity of protein isolated reached 81.18%.
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