Profiling and putative aroma biomarker identification for flavor in potatoes using a trained sensory panel and HS-SPME GC-MS
Date
2017
Authors
Bough, Raven, author
Jayanty, Sastry, advisor
Holm, David G., advisor
Stone, Martha, committee member
Journal Title
Journal ISSN
Volume Title
Abstract
Flavor is the synthesis of taste and aroma sensations. The taste fraction of flavor, including salty, sweet, sour, bitter, and savory, refers to non-volatile chemical compounds that are detected by epithelial cells in the mouth. The aroma fraction encompasses volatile or semi-volatile chemical compounds that are sensed by nerve cells within the olfactory system, particularly during the chewing process, initiating a multitude of sensations such as earthy, floral, or fruity. Flavor may also be influenced by texture, sound, appearance, or personal preference, resulting in an inherently complex phenotypic trait that is difficult to assess. Cooked flavor profiling of fifteen fresh market potato clones (Solanum tuberosum, L.) using sensory analysis paired to aroma compound analysis reveals potential biomarkers for flavor phenotyping. Trained sensory panelists described extensive, significant sensory differences between potatoes including bitter, buttery, creamy, earthy, fruity, off-flavors other than bitter, potato-like flavor, sweet, woody, appearance, aroma intensity, mealy texture, and overall quality (mixed model ANOVA, α=0.05, n=17-38 ratings x 15 clones). Non-targeted volatile metabolomics with headspace solid-phase microextraction gas chromatography coupled to mass spectrometry (HS-SPME GC-MS) facilitated identification of 42 unique metabolites with significant variation across samples (ANOVA, α=0.05, n=5 technical replicates x 14-15 clones x 2 cooking methods). Based on Spearman's rank correlations, hierarchical clustering analysis (HCA), and principal component analysis (PCA), potential biomarkers for buttery, a positive flavor attribute, are aldehydes 1-nonanal, benzaldehyde, (E)-2-heptenal, pentanal, 2-phenylacetaldehyde, the alcohol (Z)-2-methyl-2-penten-1-ol, and 5-methyl-2-hexanone, a ketone. Other positive flavor attributes, sweet and potato-like flavor, are related to benzoate-3-methyl-2-buten-1-ol, 2-ethylfuran, and 3,4,5-trimethyl-2-cyclopenten-1-one. Potential biomarkers for negative flavor attributes are also implicated. Additionally, some sensory and aroma compound differences occur between baked versus boiled potatoes. Flavor biomarkers may play a key role in achieving flavor quality improvement through breeding and selection.