Study On The Purification Ofα-linolenic Acid From Rubber Seed Oil

a-linolenic acid is the focus of current research of functional food, which is bound up with human’s physical growth and health, which is one kind of essential fatty acids that the body can not synthesize itself, but can only get from the diet. In order to obtain high purity a-linolenic acid, α-linolenic acid from natural plants oil that the content of a-linolenic acid is generally low needs to be enriched.The content of multivalent unsaturated fatty acid of rubber seed oil is59.13%, and the content of a-linolenic acid is16.7%, which is a kind of high quality and cheap source of a-linolenic acid. The rubber seed kernel oil in the rubber seed was extracted by n-hexane in this study, and its Physical and chemical properties and fatty acid composition were studied too, mixed fatty acid prepared by saponification was purified by using a variety of purification technology and high purity of a-linolenic acid products were obtained.1. The optimum conditions of hydrolysis of rubber seed oil were found as follows:the concentration of NaOH was1.0mol/L, saponifying temperature was60℃,saponifying time was40min, the radio of oil to ethanol solution1:5, Saponification liquid was stood for12h in the fridge upper. The color of mixed fatty acid made in this condition was shallow, a light yellow. The content of a-linolenic acid and linoleic acid are16.7%and41.42%respectively.2. Mixed fatty acid was treated to separate polyunsaturated fatty acids(PUFA) by using low temperature crystallization after single factor test. Results showed that:the optimal conditions were as follows:n-hexane as a solvent, The ratio of mixed fatty acid mass to n-hexane volume1:10, crystallization temperature-70℃, freezing time1.5h, refrigerated centrifuge3min at-18. In the best condition, the content of unsaturated fatty acids (UFA) is up to98.67%,and PUFA increase from58.12%to71.52%.in fatty acid I.3. a-linolenic acid was separated with double solvent freezing crystallization. The results from orthogonal experiments showed that the optimum seperation conditions were: using acetonitrile and acetone mixed solution as solvent, the ratio of acetonitrile volume to acetone volume4:6, the ratio of mixed fatty acid mass to acetonitrile and acetone volume1:15, freezing crystallization time for10h, solid-liquid separation methods for-18℃,7000r/min refrigerated centrifuge3min. The results show that the relative content of a-linolenic acid from rubber seed oil increase from16.32%to31.52%, the content of total unsaturated fatty acid is also up to98.28%.4. a-linolenic acid of rubber seed oil was separated with Secondary double solvent freezing crystallization with the response surface method. The optimization was carried out based on the basis of three process parameters, namely the ratio of acetonitrile and acetone volume to fatty acid I mass, the ratio of acetonitrile volume to acetone volume and frozen time as the experimental factor and the content of a-linolenic acid as response value. The results showed that using acetonitrile and acetone mixed solution as solvent, The ratio of acetonitrile and acetone volume to fatty acid I mass18:1, the ratio of acetonitrile volume to acetone volume1.5:1, freezing crystallization time for9h, solid-liquid separation methods for-18℃,7000R/MIN refrigerated centrifuge3min. In the best condition, the content of a-linolenic acid in rubber seed oil reach to45.41%.5. The optimal condition of separating a-linolenic acid by urea adduction fractionation was:fatty acid I to urea mass to Urea inclusion medium volume1:4:12, inclusion temperature30℃, the closure time12h. The results show that the content of a-linolenic acid and linoleic acid in fatty acid I reach to36.15%and66.16%respectively。6. Expermients for separation of a-linolenic acid from rubber seed oil were performed using aqueous AgNO3extraction, the content of a-linolenic acid reach to94.99%.