*2.1. Supercritical Fluid Extraction of Avocado Oil*

Generally, avocado oil is extracted from avocado pulp by centrifugation, cold pressing or solvent extraction [26]. These extraction methods are time-consuming and economically unfavorable. Supercritical fluid extraction (SFE), on the other hand, is an environmentally friendly and cost-effective extraction method with a multitude of applications in the food, pharmaceutical and fine chemical industries. In the present study, SFE was used for the extraction of oils from avocado peel, pulp and seed. The yields of the oils along with their physicochemical properties determined by the standard method of the American Oil Chemists' Society [27] were compared with the oils extracted with the AOAC method [28]. The results are given in Table 1. The color of the oils extracted from the SFE method was much lighter than that of the solvent extraction, indicating a smaller amount of chlorophyll being extracted. The TG and FA profiles for these two extraction methods were similar as determined by UHPLC/MS and GC/MS analysis. Therefore, the oils extracted by SFE were used for further studies.


**Table 1.** Extraction conditions, oil yields and physicochemical properties (mean ± SD, *n* = 3).

\*,a: Oil yields were calculated based on the dry weight. \*,b: Not enough quantity to perform the measurements.
