Study On Analysis And Enrichment Process Of Alkylglycerols From Shark Liver Oil

Alkylglycerol（sAKGs）were proved to enhance the body immunity and removefree radicals in cells，in addition, they were shown to have anti-tumor effects andreduce the damages caused by radiation and chemotherapy. There are many kinds ofAKGs varying by the chain length and saturation, and the bio-active functions aredifferent. A study has proved that C18:1-AKG and C16:1-AKG have higheranti-tumor activities than other AKGs.Shark liver oil（SLO）is the primary source of AKGs at present, and the contentof AKGs in commercial shark liver oil is20%. The chemosynthetic batyl alcohol, anauxiliary treatment agents of white blood cells reduce disease, is another AKGsproduct besides shark liver oil, however, the bio-activity of chemosynthetic AKGs arerelatively lower.AKGs exist in the form of Di-esterified AKGs（DEAKGs）in shark liver oil,,and the similar structure between DEAKGs and triacylglycerides（TAG） makes itcomplicated to purify the AKGs. Due to the lack of purification technology, manymanufacturers disposed of SLO after squalene extraction, leading to the huge waste ofresources. The purpose of this paper is to improve the addition value of SLO byenrichment of AKGs.For the purpose of the paper, the following work were performed. Firstly,related lipid analysis of SLO was carried out. Afterwards AKGs from SLO、severalmarine and dairy resources were analyzed with the TLC and GC-MS. Then anenrichment method of AKGs combining ethyl esterification and molecular distillationwas established. The main results are as follows.1.The basic lipid composition of SLO was determined. The results indicated thecontent of PUFA reached to51%, and contents of DHA and EPA were11.0%and8.9%of total fatty acids, respectively. Content of AKGs was5.3%andunsaponifiable matters were8.03%. The basic lipid compositions indicated that SLO is a promising source of AKGs-enrichment and n-3PUFA, therefore furtherexploration is needed for more efficient utilization of SLO.2. Thin-Layer Chromatography and silylation derivatization with GasChromatography-Mass Spectrum were used to detect the AKGs compositions of SLOand several resources.（1）14types of AKG were detected from SLO, and C18:1-AKG was the majorcomponent with content of43.76%, followed by C16:0-AKG（22.99%） andC18:0-AKG（16.21%）. Content of unsaturated AKGs was53.41%. The aboveresults showed that the SLO is worthy of development with optimal compositions ofAKGs.（2）11,7and7kinds ofAKGs were detected from star fish lipid、sea eel oil andtuna oil respectively. C18:0-AKG and C16:0-AKG were the predominantcomponents in these three marine resources, C14:0-AKG and C16:1-AKG werealoso higher than those of SLO.7,3and3kinds AKGs were found in lipids ofbreast milk、milk and milk powder, and for breast milk and milk, C18:1-AKG wasthe main components with contents of41.03%and46.17%, respectively, whileC16:0-AKG being the major part of milk powder with a content of39.83%. Theabove results showed that compositions of AKGs varied in marine and dairyresources, the corresponding development could carried out by different demands,and the results can be used as the theoretical foundation in the seek of new reacoucesof AKGs.3. The ethyl esterification reaction of SLO, a process for transferring theDEAKGs into AKGs, was studied. Effect of reaction factors on ethyl esterificationwas investigated by single-factor and orthogonal experiments. The optimum reactionconditions obtained were listed, reaction time2h, methanol-oil ratio6:1, catalystconcentration1%and reaction temperature50℃. The esterification degree was88.65%under this optimum reaction conditions. And the esterification degreedeclined very slightly（85.28%）with the growing of the reaction scales. The ethylesterification process laid a foundation for the following enrichment.4. Based on the molecular distillation technology, the effect of reaction factors on molecular distillation was studied, and enrichment method of AKGs by moleculardistillation was established. The optimalizing reaction condition was confirmed bythe contents and compositions of AKGs and FAEE of heavy and light phase, heatingtemperature120℃，charging rate2mL/min and rotor speed150rpm. Under thefavorable reaction conditions, the ratio of heavy phase was16.7%, and the content ofAKGs was22.9%with51.72%of significant efficacy AKGs, the recovery rate ofAKGs was72%. The high-value use of SLO was achieved by enriching the AKGswith this method.