| Torreya grandis is unique economic tree species in China,and it has been promoted as quality woody oil-plant.and Torreya grandis Fort.var.Merrillii has been regarded as one of the key development of woody oil-plant by the State Forestry Administration.The unsaturated fatty acid content of Torreya grandis seed oil is up to approximately 90%,mainly including oleic acid,linoleic acid and sciadonic acid.In addition,Torreya grandis seed oil is rich in tocopherols,sterols,squalene,polyphenols and other trace nutrients.At present,the industrialscale production of Torreya grandis seed oil has not been realized because there is no systematic study on Torreya grandis seed oil,especially on production process of Torreya grandis seed oil.This study is to investigate the composition of Torreya grandis seed oil from different varieties and regions by gas chromatography,liquid chromatography and gas chromatography-mass spectrometry,and evaluate the effects of varieties,regions and production process of Torreya grandis seed oil on trace nutrients and free radical scavenging activity.Firstly,the indexs of Torreya grandis were measured,then physicochemical characteristic,fatty acid composition and sn-2 fatty acid composition of Torreya grandis seed oil were analyzed,and the structure of the special fatty acid was identified by GC-MS and FT-IR.Oil content of Torreya grandis was 40.39%~52.80%,the acid value of Torreya grandis seed oil was 0.17~2.91 mg KOH/g,and the peroxide value was 0.09~0.99 mmol/kg,which was in accordance with the general requirements of edible vegetable oil.The special fatty acid of Torreya grandis seed oil was cis 5,11,14-eicosatrienoic acid(sciadonic acid).Palmitic acid was 7.60%~9.28%,stearic acid was 2.43%~2.95%,oleic acid was 23.08%~33.21%,linoleic acid was 41.51%~43.20%,cis-11,14-eicosadienoic acid was 2.24%~3.64%,sciadonic acid was 9.45%~14.28%.At the sn-2 position,the content of unsaturated fatty acid was more than 96%,the sum content of oleic acid and linoleic acid was more than 90%,and most of oleic acid was located at the sn-2 position.Secondly,the differences of the total fatty acid composition,trace nutrients contents and free radical scavenging activity of the oils obtained from the different varieties and regions were analyzed,and the correlation between trace nutrients and the free radical scavenging activity was studied.The contents of fatty acids in different varieties of Torreya grandis seed oils were significantly different.Palmitic acid,linoleic acid and sciadonic acid in Torreya grandis Fort.ex Lindl.seed oil were higher than those in Torreya grandis Fort.var.Merrillii seed oil,while oleic acid in Torreya grandis Fort.ex Lindl.seed oil was lower than that in the latter.In the aspect of trace nutrients,tocopherol was 1955.47~2141.94 mg/kg,sterols was 1672.11~2528.19 mg/kg,squalene was 31.07~37.24 mg/kg,polyphenol was 66.02~98.41 mg/kg in Torreya grandis Fort.ex Lindl.seed oil.Tocopherol was 1520.05~1620.83 mg/kg,sterols was 1407.81~1777.11 mg/kg,squalene was 14.29~16.77 mg/kg,polyphenol was 18.04~30.33 mg/kg.The contents of tocopherol,sterols,squalene and polyphenols in Torreya grandis Fort.ex Lindl.seed oil were significantly higher than those in Torreya grandis Fort.var.Merrillii seed oil,and Fuyang and Zhuji was the highest.In the aspect of free radical scavenging activity,the scavenging activities of ORAC,ABTS,FRAP and DPPH of Torreya grandis Fort.ex Lindl.seed oil were better than those of Torreya grandis Fort.var.Merrillii seed oil.The contents of tocopherols,squalene and polyphenols were significantly correlated with the scavenging ability of FRAP,DPPH,ORAC and ABTS.In terms of the species of Torreya grandis,the contents of trace nutrients and free radical scavenging activity of Torreya grandis Fort.ex Lindl.seed oil were superior to those of Torreya grandis Fort.var.Merrillii seed oil.In terms of the production of Torreya grandis,Fuyang and Zhuji were more advantageous.Finally,physicochemical characteristic,trace nutrients composition and free radical scavenging activity of Torreya grandis seed oil extracted from different techniques were measured,then the effects of production process on the oil were evaluated.The acid value and peroxide value in the oil extracted from hot pressing were the highest among the three producing technologies,both to which met the general requirements of edible vegetable oil.In terms of trace nutrients,the contents of sterols(1600.85~2048.11 mg/kg),squalene(16.16~30.85 mg/kg)and polyphenols(31.09~61.84 mg/kg)in the oil extracted from hot pressing were much higher than those in the other oils,whereas the tocopherol content(1592.38~2256.56 mg/kg)in the oil extracted from hot pressing was slightly lower than that in the oil extracted from solvent extraction.In the aspect of free radical scavenging activity,the scavenging free radicals of ORAC and ABTS were strongest,and the scavenging ability of FRAP and DPPH was similar to the oil extracted from solvent extraction.The effect of oil production on the quality of Torreya grandis was consistent with its general rule on the quality of similar products.In terms of the oil production process,the amounts of trace nutrients and the free radical scavenging activity in the oil extracted from hot pressing have obvious advantages over the other techniques. |
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