Analysis of Volatile Composition and Key Aroma Compounds in Toddalia asiatica Lam. Honey

In order to clarify the volatile composition and aroma characteristics of Toddalia asiatica Lam. honey, a Chinese specialty herbal honey, this study determined its selected physicochemical indexes such as water content, sugar content, amylase activity, and antioxidant capacity by using an Abbey refractometer, high-performance liquid chromatography (HPLC), and ultraviolet-visible spectrophotometry, respectively. Meanwhile, its volatile components were qualitatively and quantitatively analyzed using headspace-solid phase microextraction combined with gas chromatography-quadrupole time-of-flight mass spectrometry (HS-SPME-GC-Q-TOF-MS). The results showed that T. asiatica Lam. honey contained (18.71 ± 1.49)% moisture, (35.92 ± 2.70)% fructose and (35.85 ± 2.51)% glucose, and could scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical with half-maximum inhibitory concentration (IC50) values of (57.18 ± 7.62) and (247.68 ± 40.50) mg/mL, respectively, and its amylase activity was (11.84 ± 3.38) mL/(g·h). A total of 176 volatile substances were identified from the honey, mainly including 52 hydrocarbons, 29 esters, 21 alcohols, 21 terpenes, 17 aldehydes, and 12 aromatics. Among them, the contents of benzaldehyde, phenylethanol and 1-octene-3-alcohol were high (8 181.9, 4 483.1 and 4 239.5 μg/kg, respectively). Totally 42 key aroma compounds, with odor activity values (OAV) greater than 1, were identified, including damastone, methyl phenylacetate and α-cresine, which contributed significantly to the aroma composition of T. asiatica Lam. honey. Among them, violonone had a violet flower-like aroma, being responsible for the unique violet- and raspberry-like aroma notes of T. asiatica Lam. honey. Overall, T. asiatica Lam. honey was dominated by floral aromas, along with fruity, chemical, and green aromas. In summary, the physicochemical indexes of the honey meet the relevant standards, and it contains a variety of volatile components. This study could provide data support for the quality evaluation of T. asiatica Lam. honey, as well as research ideas for the excavation of other Chinese specialty herbal honeys.