Abstract:

Benzoic-type and cinnamic-type phenolic acids were extracted from Guanxi pomelo peel by ultrasoundassisted
extraction with a 60 kHz frequency. High-performance liquid chromatography (HPLC) coupled with a
photodiode array detector was applied for the analysis of phenolic acids after alkaline hydrolysis, and the effect of
ultrasound on the stability of phenolic acids was investigated. The results showed that seven phenolic acids underwent
different degrees of degradation during 60 min of ultrasound treatment at a relatively higher temperature of 40 ℃, but
ultrasound power did not have the same effect on the stability of phenolic acids in pomelo peel as treatment time or
temperature. The heat stability of benzoic-type phenolic acids was overall better than that of cinnamic-type phenolic
acids. Furthermore, the optimal extraction conditions of individual phenolic acids were different showing different
degrees of degradation.

Key words: ultrasound-assisted extraction, Guanxi pomelo peel, phenolic acids, stability