Optimization of low power ultrasound-assisted extraction of phenolic compounds from mandarin (Citrus reticulata Blanco cv. Sainampueng) peel

Mandarin peel is a good source of phenolic compounds, which can be extracted by the ultrasound-assisted extraction (UAE) method. This research was to optimize the UAE conditions for maximum mandarin peel extract (MPE) relating to the extract yield, total phenolic content and the content of a mandarin peel rich flavonoid, hesperidin, using a response surface method comparing with the maceration extraction (MAE) method. The results showed that the selected factors (temperature, time and power) have a significant influence on the extraction yield, total phenolic content and hesperidin content. The extraction at 48 degrees C and 56.71 W for 40 min was considered the optimal UAE condition since it provided the maximum yield (26.52%), total phenolic (15,263.32 mg Eq gallic/100 g DW) and hesperidin (6435.53 mg/100 g DW). At the same extraction temperature and time, UAE showed greater extraction efficiency than MAE with 1.77 times higher yield than that of MAE.