Separation And Purification Of Individual Soybean Tocopherols And Phytosterols From Soybean Deodorizer Distillates

Soybean oil deodorizer distillates is one of the important sources for the preparation of natural tocopherols and phytosterols.Tocopherols can be divided into four individuals:α-,β-,γ- andδ- tocopherol. Among them,bioactivity ofα- tocopherol was widely known by people (prevention of risk factors of cardiovascular disease,anti-inflammation,pulmonary protective,radioprotection,neuroprotective,anticancer et al.).Presently, only high purityα- tocopherol is economically available and widely used in functional foods and pharmaceuticals . However , with the development of biomedicine and pharmacology,the bioactivity of non-alpha individual tocopherols is being further discovered.Owing to the unique biological action of non-alpha tocopherols, the need for these high purity tocopherols is increasing in the fields of functional foods, cosmetics and pharmaceuticals.Phytosterols have many important physiological functions - lower cholesterol and reduce the incidence of heart disease,anti-cancer and anti-inflammatory effects . Soybean phytosterols are maily composed ofβ-sitosterol,stigmasterol,brassicasterol and campesterol.With the development of biomedicine and pharmacology , the individual phytosterols is being widely used.Owing to the unique medicinal value of individual phytosterols, the need for these high purity phytosterols(especially stigmasterol ) is increasing in the fields of functional cosmetics and pharmaceuticals. Therefore , how to separate tocopherols and phytosterols into individual products and enhance their purity and yield become a refining hotspot presently.Aiming at the actuality of the utilization of the tocopherols and phytosterols,we used soybean tocopherols and phytosterols(obtained from soybean oil deodorizer distillates)as raw material to prepare individual tocopherols and phytosterols product. The main contents studied are as follows:1. The individual tocopherols is separated by using low-pressure column chromatography.α-Tocopherol,γ-tocopherol andδ-tocopherol were successfully separated and purified from soybean vitamin E concentrate (53% purity, from soybean oil deodorizer distillate ) on a low-pressure glass column (500mm×25mm, I.D.,packed with silica gel). The effects of eluent, flow-rate and sample loading on separation efficiency were investigated using product purity and recovery as evaluation indices. On the basis of the single factor experiment results, an orthogonal test was designed to optimize the chromatographic separation conditions. The optimum conditions obtained by using analyses of extreme difference and variance are as follows: cyclohexane-ethanol 99.7:0.3 (v/v), flow-rate at 25ml/min and loading amount being 2ml (concentration 1g/ml). Under these optimum condition, purity of theα-tocopherol,γ-tocopherol andδ-tocopherol were 92.35%, 91.23%, 89.95%, respectively; the recovery of those products were 35.21%, 36.25%, 61.25%, respectively.2. The solubility ofβ-sitosterol and stigmasterol in cyclohexanone at different temperatures were determined.β-sitosterol and stigmasterol were separated and purified from soybean phytosterols using crystallization based on the difference of variation of the solubilities of stigmasterol andβ-sitosterol with temperature changing . The experimental results show that the purity ofβ-sitosterol is about 90% after the fourth fractional crystallization in cyclohexanene. Some parameters (ratio of material to liquid,crystallization temperature , and ripening time) were optimized for cystallization of stigmasterol as the follows : ratio of material to liquid was1:3.3,crystallization temperature was 25℃and ripening time was 5h. With above conditions, the purity of stigmasterol is about 96% after the fifth fractional crystallization in cyclohexanene.3.β-Sitosterol and stigmasterol were successfully separated and purified from soybean phytosterols(95% purity,from soybean oil deodorizer distillate)on a low-pressure glass column(200mm×12.5mm,I.D.,packed with ODS).When use methanol - isopropyl alcohol - water (85:5:10, v / v / v) as eluent,the recovery ofβ- sitosterol and stigmasterol were 53.6% and48.2%, respectively;the purity ofβ- sitosterol and stigmasterol were 84.3% and74.4%, respectively.