Analysis of the volatile compounds from Nugget hop variety by gas chromatography-mass spectrometry

Head space- solid phase microextraction- gas chromatography- mass spectrometry( HS- SPME- GC- MS) and steam distillation- gas chromatography- mass spectrometry( SD- GC- MS) were compared to analyze the volatile compounds of Nugget hop varirty grown in China. The qualitative and quantitative analysis were performed using mass spectral library retrieval combined retention index( RI) and the normalization method of peak area,respectively. Meanwhile,the content of main flavor compounds were compared with the hop grown in the USA.It was shown that the significant difference was obtained of volatile compounds of Nugget hop by HS- SPME and SD.A total of 106 volatile compounds was identified by HS- SPME,and accounted for 99.11% of the total peak area. While only total of 87 compounds was obtained by SD,accounted for 96.20%. The results showed that the main volatile composition was hydrocarbon compounds( include terpene compounds),followed by esters and alcohols.The main volatile flavor compounds were β- pinene,β- myrcene,trans- caryophyllene,α- humulene,L- linalool,etc.,which were agreed or closed to the major volatile compounds of Nugget hop variety grown in the USA.It indicated that the flavor compounds were complete in accordance with the Nugget hop variety introducted from foreign and their origin.