| Trichosanthes seed oil is rich in unsaturated fatty acid composition.The refining decolorization can improve its edible quality and commodity value.In this study,the low temperature cold pressing method was used to prepare the seed oil.Basis on the analysis of the basic indexes of the seeds oil,the decolorization process of the seeds oil was also studied.At the same time,the organic solvent was seleced,the main pigment components in trichosanthes seed oil were separated and purified by organic solvent extraction,column chromatography and preparative chromatographic separation.The components of each extraction fraction were analyzed and identified by LC-MSn and 1H-NMR.The main conclusions are as follows:(1)Comparison with the degumming effect among the enzymatic degumming,acid degumming and hydration degumming.The results showed that the content of phosphatide in trichosanthes seed oil decreased from 0.49 mg/g to 0.06 mg/g after degumming by enzymatic degumming.The content of phosphatide in trichosanthes seed oil was 0.14 mg/g after acid degumming and 0.25 mg/g after hydration degumming,which showed that the effect of enzymatic degumming was the best method for the degumming of trichosanthes seed oil.(2)On comparing with the effect of alkali refining on the decolorization in trichosanthes seed oil,it was found that alkali refining reducing the color of oil was better and help to improve the decolorization rate of Trichosanthes seed oil.In addition,the decolorization effect of activated clay was better than that of activated carbon,and the optimum conditions were as follows: the amount of activated clay was 14 g/100 g,the decolorization temperature was 95 ?,the decolorization time was 20 min.In order to keep the active clay in the oil being a state of uniform suspension without sinking under the normal pressure condition,the stirring speed should not be too strong.(3)Compared with the basic indexes before and after the decolorization of the Trichosanthes seed oil,we found that the fried seed treatment could reduce the moisture content of the seeds oil from 15.8% to 7.6%,which was beneficial to the preservation of the seeds and could also make the trichosanthes seed oil be more stabe.Before the decolorization of Trichosanthes kirilowii seed oil,the content of water and volatile matter was 0.61%,the phospholipid content was 0.49 mg/g,the acid value was 1.53(KOH)/(mg/g),the iodine value was 132.7 g I2/100 g,and the saponification value was 169.5(KOH)/(mg/g),the absorbance value of 2.511 Abs.After adopting the new process,the content of water and volatile matter was 0.08%,the phospholipid content was 0.05 mg/g,the acid value was 0.51(KOH)/(mg/g),and the iodine value was 133.6 gI2/100 g,the saponification value is 197.4(KOH)/(mg/g),the absorbance value was 0.0002 Abs,and the improved decolorization process could also retain the fragrance of Trichosanthes seed oil.(4)The analysis of the fatty acid composition in trichosanthes seed oil showed that the seed oil extracted by the cold pressing method could retain more nutritive materials,and to ensure the extraction of linolenic acid,the seeds needed to be fried before pressing.The content of polyunsaturated fatty acids in trichosanthes seed oil was 65.91%,and the content of linoleic acid was 31.94%,which included four kinds of octadecatrienoic acid,namely,soracic acid(cis 9,trans 11,cis 13 Octadecatrienoic acid)27.24%,?-tung acid(cis 9,trans 11,trans 13-octadecatrienoic acid)3.33%,?-linolenic acid(cis 9,cis 12,cis 15-Trienoic acid)3.01% and the tartic acid(trans 9,trans 11,trans 13-trioctatrienoic acid)0.39%.(5)The separation and purification of the pigments in the trichosanthes seed oil showed that the pigments had a strong absorption value at 430 nm in the ultraviolet region.The best separation effect was obtained when used the mixture of acetone,petroleum ether and methanol as extractant,and the extraction ratio was set to 3:2:5 while the best extraction time was 120 min.At the same time,this study also found that TLC method and HPLC method could play a better separation and purification effect when compared to silica gel column chromatography and macroporous resin column chromatography on the pigment composition of the seeds oil.(6)According to the LC-MSn analysis,it was found that the pigment elements in the seeds oil were complex and diverse.Reference to the relevant literature,we made a preliminary speculation that the signals of [M-H]-m/z 453.5,[M-H]-m/z 536.3,[M-H]-m/z 615.3 and [M-H]-m/z 641.1 might be flavonoids,beta-carotene,chlorophyll a and fucoidin.The results showed that the flavonoids,flavonols,isoflavones,dihydrogen flavonoids,diisoflavones and flavonoids such as flavonoids could be deduced by 1H-NMR analysis of the unknown pigment components in the seeds oil,which indicated that there were certain flavonoids in the pigments. |
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