海豹油n-3PUFA富集过程中品质及挥发性物质的变化

以海豹油乙酯为原料,采用尿包法和分子蒸馏法对其中的n-3PUFA进行富集,通过理化分析、气相色谱(GC)及顶空固相微萃取-气-质谱联用(HS-SPME-GC-MS)等技术研究富集过程中样品品质、脂肪酸组成和挥发性物质的变化。结果表明:尿包法和分子蒸馏法可以显著提高样品的皂化值和碘值,对酸价和过氧化物值影响不大。尿包法可以显著降低样品中饱和脂肪酸(SFA)的含量,提高n-3多不饱和脂肪酸(n-3PUFA)的含量,然而对某些长链单不饱和脂肪酸(MUFA)(C16:1,C18:1和C20:1)的分离效果有限。分子蒸馏法可有效分离SFA和MUFA,得到含量高达92.96%的n-3PUFA浓缩产物。尿包法和分子蒸馏法对样品中挥发性物质种类影响不大,而对样品中挥发性物质的含量影响显著,尿包法可显著增加样品中挥发性物质的含量,分子蒸馏则相反。其中,贡献较大的挥发性物质主要为乙醇、2-乙基己醇、十五碳烯醇、壬醛、十一醛、3,5-辛二烯-2-酮、2-壬酮、2-庚酮。

The Changes of Quality and Volatile Substance of the Seal Oil during the n-3PUFA Enrichment Processing

The n-3PUFA in the seal oil ethyl ester was enriched by urea adduction and molecular distillation.The physicochemical index,fatty acid composition and volatile substance in the seal oil during the enrichment were analyzed by physicochemical analysis,GC and HS-SPME-GC-MS.The results showed that the saponification value and iodine value were significantly improved by urea adduction and molecular distillation while had no significant effect on the acid value and peroxide value.The content of SFA was significantly decreased after urea adduction while n-3PUFA present the opposite tendency.There was a significant decrease in the content of MUFA.However,some long chain MUFA(C16:1,C18:1 and C20:1)still occupied larger percentage.The SFA and MUFA were separated effectively after molecular distillation and products with n-3PUFA content of 92.96%were obtained.There was no significant difference in the quantity of volatile substances between the material,urea adduction sample and molecular sample.The content of volatile substances in the urea adduction sample was significantly higher than the material and the material was significantly higher than that of the molecular distillation sample.The main volatile substances that contribute to the change were ethanol,2-ethyl hexanol,fifteen carbon enol,nonanal,undecanal,3,5-octadien-2-one,2-nonanone,2-heptanone.