Microwave-assisted extraction of silkworm pupal oil and evaluation of its fatty acid composition, physicochemical properties and antioxidant activities

- MAE is an effective method in the extraction of silkworm pupal oil.
- MAE process is optimised by response surface methodology.
- Oil by MAE reveals similar fatty acid composition with oil by Soxhlet extraction.
- Oil by MAE exhibits superior physicochemical properties and antioxidant activities.
- SEM shows that MAE promotes the release of oil by breaking down the cell structure.

Microwave-assisted extraction (MAE) of oil from silkworm pupae was firstly performed in the present research. The response surface methodology was applied to optimize the parameters for MAE. The yield of oil by MAE was 30.16% under optimal conditions of a mixed solvent consisting of ethanol and n-hexane (1:1, v/v), microwave power (360 W), liquid to solid ratio (7.5/1 mL/g), microwave time (29 min). Moreover, oil extracted by MAE was quantitatively (yield) and qualitatively (fatty acid profile) similar to those obtained using Soxhlet extraction (SE), but oil extracted by MAE exhibited favourable physicochemical properties and oxidation stability. Additionally, oil extracted by MAE had a higher content of total phenolic, and it showed stronger antioxidant activities. Scanning electron microscopy revealed that microwave technique efficiently promoted the release of oil by breaking down the cell structure of silkworm pupae. Therefore, MAE can be an effective method for the silkworm pupal oil extraction.