Characterization of flavor and taste profile of different radish (Raphanus Sativus L.) varieties by headspace-gas chromatography-ion mobility spectrometry (GC/IMS) and E-nose/tongue

Abstract

A comprehensive study of the overall flavor and taste profile of different radishes is lacking. This study systematically compared the volatile profile of six radish varieties using HS-GC-IMS and their correlation with the E-nose analysis. Organic acids and amino acids were quantified, and their association with the E-tongues analysis was explored. A total of 73 volatile compounds were identified, with diallyl sulfide and dimethyl disulfide being the primary sulfides responsible for the unpleasant flavor in radish. Compared to other varieties, cherry radishes boast a significantly higher concentration of allyl isothiocyanate, which likely contributes to their characteristic radish flavor. Moreover, oxalic acid was identified as the most abundant organic acid in radish, accounting for over 97% of its content, followed by malic acid and succinic acid. In conclusion, the distinct flavor and taste characteristics of different radish varieties partially explain their suitability for diverse culinary preferences.

Keywords: E-nose; E-tongue; GC/IMS; Radish; Volatile compounds.

Fig. 1

Radish varieties with different shapes, skin colors, and flesh colors. Including white-skinned, white-fleshed and long-rooted radish (WW), red-skinned, white-fleshed and long-rooted radish (RW), red-skinned, red-fleshed and long-rooted radish (RR), green-skinned, green-fleshed and long-rooted radish (GG), green-skinned, green-fleshed and round-rooted radish (GR), cherry radish (CR). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 2

PCA analysis (A) and electronic nose radar (B), PCA analysis (C) and electronic tongue radar (D) of different radish varieties raw flesh.

Fig. 3

Organic acids (A) and organic acids without oxalate (B) in different radish varieties.

Fig. 4

Free amino acids (A) and taste-active amino acids (B) in different radish varieties.

Fig. 5

HS-GC–IMS Fingerprint of VOCs (A), and aroma compounds ratio in radish varieties (B), OPLS-DA plot (C) and Variable Importance in Projection scores (VIP) diagram (D).

Fig. 6

Correlation analysis heatmap illustrates the correlation between the levels of volatile compounds and the E-nose sensor responses (A), and between organic aids/amino acids and E-tongue sensor responses (B) and cluster analysis of samples (C). In the heatmap, colors represent correlation coefficients, with green indicating positive correlations and brown indicating negative correlations. ** indicates extremely significant differences (P < 0.01), while * denotes significant differences (P < 0.05). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Supplementary Fig. S1

Three- (A) and two-dimensional (B) topographic spectra of volatile flavor compounds in different radish varieties detected by GC-IMS, and two-dimensional map of volatile flavor compounds of WW (C), RW (D), RR (E), GG (F), GR (G) and CR (H) was selected as a reference, respectively, while the plots of other samples were deducted from the reference.