Abstract: This study aimed to optimize and compare the ultrasonic assisted extraction (UAE) and the microwave assisted extraction (MAE) of proanthocyanidins from fresh flowers and essential oil extraction residue of Kushui rose. The optimization was performed using one-factor-at-a-time (OFAT) method and response surface methodology (RSM). The results of OFAT experiments showed that the optimal ultrasonic irradiation temperature and time to obtain the maximum yield of proanthocyanidins were 60 ℃ and 20 min and the optimal microwave irradiation temperature and time were 60 ℃ and 40 s, respectively. When the extraction was carried out for 1.5 h using 60% ethanol as extraction solvent at 75 ℃ with a solid-to-solvent ratio of 1:20 (g/mL), 17 min ultrasonic irradiation at 59 ℃ and 44 s microwave irradiation at 61 ℃ were found to be optimal to obtain a higher yield of proanthocyanidins of 96.94 and 100.81 mg/g from fresh rose flowers, respectively, while in the case of the oil extraction residue, 20 min ultrasonic irradiation at 60 ℃ and 42 s microwave irradiation at 60 ℃ were the optimal conditions to obtain a higher yield of proanthocyanidins of 57.74 and 58.74 mg/g, respectively. It is suggested that both ultrasonic and microwave assisted extraction were efficient to extract proanthocyanidins from fresh flowers and essential oil extraction resident of Kushui rose, and microwave assisted extraction showed better extraction efficiency.

Key words: proanthocyanidins, optimization of extraction process, rose flowers and essential oil extraction residue, ultrasonic, microwave