南美白对虾腐败过程中挥发性成分的测定

Determination of volatile components of pena eus vanm amei during spoilage

在南美白对虾在25℃贮藏不同时间后,对虾新鲜度进行感官评价、挥发性盐基氮含量和挥发性成分的测定。虾在不同新鲜程度下挥发性成分的变化采用顶空固相微萃取-气相色谱-质谱联用(HS-SPME-GC-MS)技术进行考察。25℃贮藏24h的虾,感官评分为9分,挥发性盐基氮含量接近50mg/100g,大于中国国标规定的30mg/100g,为变质虾,失去食用价值。结合感官评定和挥发性盐基氮的测定,25℃贮藏虾挥发性成分测定结果显示,不同新鲜度的虾挥发性成分有很大差异,随着新鲜程度的降低,出现了二甲基二硫、二甲基三硫、吲哚等物质,且含量逐渐增加。结果表明,HS-SPME-GC-MS可以检测到这些物质的变化,因此可尝试用HS-SPME-GC-MS技术来评价虾新鲜度。

Penaeus vannamei prawn was stored at 25℃for different time.Its freshness was assessed by sensory evaluation,total volatile base-nitrogen（TVBN）and analysis of the volatile composition of Penaeus vannamei.The technology of headspace solid-phase microextraction gas chromatography-mass spectrometry（HS-SPME-GC-MS）was used to analyze changes in the volatile composition of Penaeus vannamei with different freshness.9was the sensory score of Penaeus vannamei stored at 25℃for 24hours,the TVBN was close to 50mg/100g,greater than the value of national standard 30mg/100g,and the prawn was unedible.Combined with the sensory evaluation and TVBN,the Penaeus vannamei samples with different freshness showed a big difference in their volatile composition.Along with the decrease in freshness,some compounds were detected including disulfide dimethyl,dimethyl trisulfide,indole and so on,and the relative contents of those compounds were increased with the extension of storage time.Our results indicated that HS-SPME-GC-MS could detect these changes of compounds in Penaeus vannamei with different freshness,therefore the technology of HS-SPME-GCMS was tried to evaluate the freshness of Penaeus vannamei.