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

Abstract

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.

Peanut Coffee: Enhancement of Nutritional, Physicochemical, and Sensory Characteristics in Coffee Brewed with Conventional and High-Oleic Peanut Extracts

“…Although caffeine was found in high concentration in this study, it is known as an odorless compound [ 41 ], and thereby was not perceivable during the sniffing test. A similar trend was also evident in a recent study showing that tridecane existed in the highest concentration, but was not detectable through sniffing test, in Platycodon grandiflorum roots [ 19 ].…”

“…High-oleic peanut coffee exhibited lower bitterness compared to normal coffee, which may be attributed to a decrease in the phenylalanine ( Table 1 ) and caffeine contents ( Table 2 ) that are associated with bitterness [ 21 ]. Previous studies also demonstrated similar results, showing that changes in phenylalanine and caffeine content upon roasting were linked to the bitterness of Platycodon grandiflorum roots and peanut sprout extracts [ 19 , 30 ]. Peanut coffee showed higher saltiness, umami taste, and sweetness than normal coffee.…”

“…Compared to normal coffee, conventional peanut coffee and high-oleic peanut coffee contained more types of alcohols, acids, esters, heterocyclics, and ketones. Maillard reaction occurs during peanut roasting and synthesizes volatile compounds, resulting in a larger number of types of volatile compounds in peanut coffee compared to normal coffee [ 19 , 30 ]. The present study also identified two hydrocarbons in normal coffee that were not found in peanut coffee, 6-aza-5,7,12,14-tetrathia pentadecane and β-bourbonene.…”

“…The literature highlighted that pyrazine complexly interacts with other volatile compounds to develop coffee flavor [ 7 ]. Recent studies also identified various pyrazines including 3-ethyl-2,5-dimethyl-pyrazine and 2-ehtyl-3,6-dimehtyl pyrazine in roasted oriental herb samples and reported roasted odor descriptions through sniffing test [ 19 , 20 ]. 2,2-Methylenebisfuran (17.6 min) and furfuryl propionate (17.7 min) were found in conventional peanut coffee and high-oleic peanut coffee, which perceived peanut and roasted odors in the sniffing test, respectively.…”

“…Olfactory intensities perceived by the panelists were expressed in the numbers 1 to 4 and a higher number indicates stronger olfactory intensity. [ 19 ].…”