Abstract:

In order to establish the best extraction method for evaluating volatile aroma composition of Zhahaijiao, a
traditional Chinese fermented chili product, changes in the aroma compounds of the Zhahaijiao made with japonica rice
powder during fermentation were determined comparatively by solid phase micro extraction (SPME) and simultaneous
distillation extraction (SDE) combined with gas chromatography-mass spectrometry (GC-MS). Besides, changes in sensory
qualities were also evaluated. SPME could extract 76, 131 and 122 of volatile components from Zhahaijiao fermented for
0, 45 and 90 days, respectively, whereas SDE could extract 23, 42 and 82 of volatile components from the three samples,
respectively. With the extension of fermentation time, the contents of aroma components extracted by SDE increased
continuously while those obtained by SPME reached the highest level at 45 days and kept stable. Esters were the major
volatile components in the fermentation process. Totally 42–50 and 15–27 volatile esters with relative contents of 46.7%–
55.3% and 60.28%–67.28% were extracted from Zhahaijiao fermented for 45–90 days by SDE and SPME, respectively.
More alcohols (14–21 alcohols, accounting for 15.7%–22.6% of the total volatiles) and aldehydes (17 aldehydes, accounting
for 5.8%–12.3% of the total volatiles) could be detected from Zhahaijiao fermented for 45–90 days by SPME. Meanwhile,
more low-boiling-point and small-molecule compounds were extracted by SPME, while more high-boiling-point compounds
were obtained by SDE. The sensory evaluation showed that the 45-day fermented Zhahaijiao had a bright color, special sour
taste and mellow flavor. These results showed that SPME combined with SDE allowed more comprehensive and objective
evaluation of volatile aroma composition of Zhahaijiao and that the optimal fermentation time for Zhahaijiao made with
japonica rice powder was 45–90 days.

Key words: Zhahaijiao, natural fermentation, simultaneous distillation extraction (SDE), solid phase microextraction(SPME), volatile components