The effect of short-term storage temperature on the key headspace volatile compounds observed in Canadian faba bean flour.

The odour emitted from the high-tannin fab bean flour (Vicia faba var. minor), was characterized by headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS). The relative odour activity value (ROAV) was used to monitor the changes in key volatile compounds in the flour during short-term storage at different temperature conditions. The key flavour compounds of freshly milled flour included hexanal, octanal, nonanal, decanal, 3-methylbutanal, phenyl acetaldehyde, (E)-2-nonenal, 1-hexanol, phenyl ethyl alcohol, 1-octen-3-ol, ß-linalool, acetic acid, octanoic acid, and 3-methylbutyric acid; these are oxidative degradation products of unsaturated fatty acids and amino acids. Despite the low lipid content of faba beans, the abundances of aldehydes arising during room temperature storage greatly contributed to the flavour of the flour due to their very low odour thresholds. Two of the key volatiles responsible for beany flavour in flour (hexanal, nonanal) increased greatly after 2 weeks of storage at room temperature or under refrigerated conditions. These volatile oxidation products may arise as a result of enzymatic activity on unsaturated fatty acids, and was seen to be arrested by freezing the flour.

Characterisation of the volatile flavour compounds in low and high tannin faba beans (Vicia faba var. minor) grown in Alberta, Canada.

The volatile flavour profiles of Canadian-grown faba beans (Vicia faba var. minor) were evaluated by headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). Two low- and high-tannin varieties were chosen, each in the form of dehulled and whole seed flours (DLT, DHT, WLT, and WHT, respectively). Pre-incubation time, fibre-extraction time, extraction temperature, and sample amount were evaluated during method optimization. The volatiles identified were classified into nine groups: aromatic hydrocarbons, aldehydes, alkanes, alkenes, alcohols, ketones, organic acids, esters, and others. Significant differences between dehulled and whole samples were found. Volatiles derived from amino acids were consistently observed in the volatile profile of all types. Despite the low lipid content of faba bean, significant amounts of volatiles normally associated with unsaturated fatty acids were present. HS-SPME/GC-MS proved to be a rapid, effective, and reproducible method (typical RSD < 5%) suitable for routine evaluation of faba bean volatile flavours.