Analysis of aroma in freshly squeezed strawberry juice during cold storage by E-nose, HS-SPME-GC-MS and GC-IMS

“Hong Yan” (HY) and “Xiao Bai” (XB) strawberries were planted widely in Jiangsu province. Aroma profile affecting the economic value of HY and XB freshly squeezed juice during cold storage (4 ± 1 ºC) is unclear. Thus, flavor of “Hong Yan” (HY) and “Xiao Bai” (XB) strawberry freshly squeezed juice were studied by electronic nose (E-nose), headspace solid phase micro extraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace-gas chromatography-ion mobility spectrometry (GC-IMS) during storage at 4 ± 1 ºC. HY and XB freshly squeezed juice could be distinguished by principal component analysis (PCA) and linear discriminant analysis (LDA) in E-nose analysis during cold storage. 17 and 21 volatile organic compounds (VOCs) in HY and XB freshly squeezed juice at different storage time were detected by HS-SPME-GC-MS, while 50 VOCs in both by GC-IMS, including esters, aldehydes, ketones and alcohols. Characteristic VOCs were identified as hexanal, methylpropanal, 5-methyl-furfural, 2-furfural, benzy alcohol, 1-hexanol, 2,6 dimethyl-4-heptanone and dipropyl disulfide in HY freshly squeezed juice, while hexyl acetate, ethyl 3-methylbutyrate, propyl hexanoate, octanal, (E)-2-octenal and 2-furfural in XB freshly squeezed juice. Results from this study advanced the understanding of VOCs in HY and XB freshly squeezed strawberry juice and could provide the basis for the in-depth research on the flavor characteristic of freshly squeezed strawberry juice.