Elucidating the flavour of cooked white asparagus by combining metabolomics and taste panel analysis

A typical feature of cooked white spears of Asparagus officinalis is their specific flavour. This has been the focus of several recent instrumental and panel studies. Few of these report on the comparison of raw and cooked materials which may lead to a deeper understanding of the flavour chemistry and compositional shifts occurring during food preparation. Here, solid-phase microextraction GC-MS and LC-MS analyses of raw and cooked spears were performed to profile asparagus metabolites. A taste panel evaluated flavour attributes of the same materials. Unsupervised and supervised statistical approaches were applied to investigate the profiles and link metabolomics and sensory results. Flavonoids, saponins and medium-chain volatile carbonyls were more abundant in the raw spears while sulphur-containing volatile compounds, oxidized fatty acids and phenolic acids were more abundant in the cooked spears. GC-Olfactometry-MS was also performed and revealed 35 odour-active volatile flavour compounds. We have proposed and discussed the key biochemical pathways and chemical transformations relevant to asparagus ‘flavour’.