Characterization of the aroma in barley leaves from different cultivars and tillering stages by HS-SPME/GC-MS, GC-O and E-nose

Abstract

Barley leaf, as a food source with medicinal attributes, is an excellent raw material for functional food. Aroma-active compounds that characterize the unique flavor of the barely leaf is an important issue that should be clarified. Therefore, gas chromatography-mass spectrometry (GC-MS) combined with GC-olfactometry (GC-O) were employed to investigate the volatiles in barely leaves from 7 cultivars and 2 tillering stages. According to a quantitative study and odor activity value (OAV), 18 volatile compounds were identified as aroma-active components. Aldehydes and alcohols are the dominant compounds. Hexanal, 2-hexenal, and isovaleraldehyde are the most abundant compounds in the former. (E)-3-hexen-1-ol, hexanol, 1-pentene-3-ol, (E)-2-hexenol, linalool and (Z)-2-pentenol are the main aromatic active compounds in the latter. The impact of the tillering stage was more significant than that of cultivars on the characteristics of volatile compounds. Furthermore, through the multivariate statistical analysis, it was found that 9 volatile compounds with Variable Importance in Projection (VIP)≥1, including (E)-2-hexenol, (E)-3-hexene-1-ol, (Z)-2-pentenol, 2-octanone, pentadecanal, 1-penten-3-ol, linalool, 2-hexenal and hexanol, played a significant role in differentiating samples. Consistent results were also got from the quantitative descriptive analysis (QDA) and electronic nose (E-nose) measurement. Overall, it is suggested that Flower 30 and Morex are the most suitable specialized cultivars to produce barley leaf products.