Abstract:

As a new extraction technique, ultrasonic-assisted neutral protease hydrolysis (UANPH) was used to extract oil
from silkworm pupae. On the basis of single factor experiments, effects of ultrasonic power, substrate concentration and
enzyme dosage on the extraction yield of silkworm pupae oil were studied with response surface methodology. In addition,
the fatty acid composition of silkworm pupae oil was analyzed by gas chromatography (GC). The results showed that the
the extraction yield of silkworm pupae oil was affected in decreasing order by substrate concentration, enzyme dosage and
ultrasonic power. The optimized operating parameters were as follows: substrate concentration 68.2 g/L, ultrasonic power
121.6 W and enzyme dosage 2 849.4 U/g. Experiments carried out under the optimal conditions led to an extraction yield
of (90.2 ± 0.66)%. GC analysis showed that composition and contents of fatty acids in silkworm pupae oils by UANPH
extraction and traditional solvent (n-hexane) extraction were in substantial agreement. The silkworm pupae oils were mainly
composed of palmitoleic acid, palmitic acid, linolenic acid, linoleic acid, oleic acid and stearic acid.

Key words: ultrasound, aqueous enzymatic extraction, silkworm pupae oil, fatty acid composition