Platycodon grandiflorum roots: A comprehensive study on odor/aroma and chemical properties during roasting

Platycodon is a ubiquitous plant widely grown in Asia. This study investigated changes in odor/aroma associated sensory attributes and chemical properties in Platycodon grandiflorum roots upon roasting. Amino acid analysis, electronic tongue analysis, chemical property analysis, volatile compound analysis, GC-olfactometry-assisted sensory attributes, and electronic nose analysis were performed. In results, amino acid profiles showed diverse patterns. Electronic tongue analysis somewhat corresponded to the free amino acid profiles. Total phenolic content, antioxidant capacity, and browning intensity significantly increased up to 4 min and slightly decreased afterward. Various pyrazines relevant to roasted odor such as 3-ethyl-2, 5-dimethyl-pyrazine, and 2, 6-dimethyl-pyrazine were generated by roasting. In electronic nose analysis, positive odor parameter significantly increased and potential unpleasant odorants significantly decreased over time. This is believed to be the first study demonstrating overall insight on odor/aroma and chemical characteristics and utilizing objective sensory measures on roasted Platycodon grandiflorum roots for food applications. PRACTICAL APPLICATIONS: This study will be utilized (a) to researchers and food companies who are interested in medicinal foods (b) to individuals and food industry that search for changes in sensory characteristics and chemical changes of foods induced by roasting, and (c) to farmers and crop producers who look for utilization and applications of Platycodon grandiflorum roots as food sources and ingredients.

Keywords: Platycodon grandiflorum roots; SPME; electronic tongue; roasting; sensory properties; volatile compounds.