Influence of Roasting Condition on Flavor Profile of Sunflower Seeds: A flavoromics approach

Sunflower see/ds (Helianthus annuus L.) were roasted in an electric forced air oven for 15, 30, 45, and 60 min at 125, 135 and 145 °C. The effect of temperature and time on the flavor profile of the samples were evaluated by headspace solid-phase microextraction coupled with gas chromatography-mass spectroscopy (HS-SPME-GC-MS). Unsupervised Principle Component Analysis (PCA) and Agglomerative Hierarchical Clustering (AHC) multivariate statistical methods were used to visualize, group and classify the samples. 114 volatiles were identified in the roasted sunflower seeds (RSF), with terpenes (α-pinene, β-pinene), heterocyclic compounds (2-ethyl-3-methylpyrazine, 2,5-dimethylpyrazine, 2-ethyl-3,5-dimethylpyrazine, pyridine), aldehydes (2-methylbutanal, furfural, hexanal, phenylacetaldehyde), hydrocarbons (octane, 2-isobutyl-1,4-dimethylcyclohexane, 6,6-dimethylundecane), alcohol (3-methyl-2-propyl-1-pentanol), and γ-butyrolactone being dominant compounds. The content of most volatile compounds increased with increase in roasting temperature and time, such as esters, terpenes, pyrazines, aldehydes, ketones, and alcohols. 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2-ethyl-3-methylpyrazine, and 2-ethyl-3,5-dimethylpyrazine contributed to be the major role in roast and nutty flavor of the roasted sunflower seeds. Roasting at 125 °C for 45 min was found to be the better condition for roasted sunflower seeds, which gave the lowest off-flavor and burnt tastes.