Extraction and characteristics of seed kernel oil from white pitaya

Valuable oil in the seeds of white pitaya can be extracted by different methods. Traditional Soxhlet extraction was compared with microwave-assistant extraction (MAE), supercritical fluid extraction (SFE), aqueous enzymatic extraction (AEE) and a combination of microwave and AEE (MAEE) for the yield and characteristics of the oil obtained. MAEE was proven to be the best method with the highest oil yield (7.78 wt/wt%) and MAE was found to be the fastest of the above five methods. Enzymatic hydrolysis of the seed kernels enhanced the oil extraction. Acid value and saponification value of the oil yielded by five methods were significantly different. The fatty acid (FA) compositions of the oil obtained by the aforementioned methods were different and depended on the extraction conditions. The most abundant unsaturated fatty acid (UFA) and poly-unsaturated fatty acid (PUFA) in the oils were oleic acid (11.80–23.40%) and linoleic acid (25.22–54.43%). The highest content of linoleic acid was obtained by SFE (54.43%).