2.1 Materials
Qingjinju (C. microcarpa (Bunge), Rutaceae) seeds were gifted by Hainan Qingjinju Food Technology Co., Ltd. (Hainan, China) during the 2017-2018 harvest season. Approximately 10 kg of the seeds were washed, drained, and oven-dried (DAIHAN SOF-155, DAIHAN Scientific Co., Ltd., Wonju-si, Korea) at 50 °C for 5-8 h. The seed moisture content was monitored and maintained at 4.0%. Seeds were stored in a refrigerator at 3 °C prior to use.
All chemicals used in the study were of analytical and/or chromatographic grade and were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China). Standards used for chromatographic analyses were purchased from ANPEL Laboratory Technologies (Shanghai) Inc. (Shanghai, China).