Abstract:

【Objective】 The optimum conditions of Ultrasound-assisted extraction of silkworm pupa oil (SPO), physicochemical property of SPO, factors influencing SPO oxidation, and antioxidant effects of different antioxidants and several polyphenols extracts for SPO were all investigated in this paper. 【Method】 Response surface method (RSM) was used to establish the mathematical model of ultrasound-assisted extraction of SPO to obtain the optimum conditions. Fatty acid compositions and contents of SPO were tested by gas chromatography (GC). Factors influencing SPO oxidation and antioxidation stability of different antioxidants and several polyphenol extracts for SPO were investigated by Schaal oven method. 【Result】 The optimum conditions obtained through RSM analysis were as follows: ultrasonic power was 102 W, ultrasonic time was 20 min and ultrasonic temperature was 40℃. The average yield of SPO was 28.9% and the extraction rate was 96.3%. The relative content of unsaturated fatty acid in SPO was 74.2%, where oleic acid was 38.3%, α-linolenic acid was 30.2%, linoleic acid was 4.3%, palmitoleic acid was 1.0% and arachidonic acid was 0.4%. Light, metallic ions and temperature can significantly speed up SPO oxidation. Among several polyphenol extracts, gallnut tannin had the strongest antioxidant capacity. 【Conclusion】 These results suggest that Ultrasound- assisted extraction of SPO had a higher extraction rate, a less extraction time and a good product quality. SPO should be stored and processed in a lower temperature condition and avoid light and metallic ions. Gallnut tannin could be used as a good natural antioxidant in SPO.

Key words: silkworm pupa oil')">silkworm pupa oil, ultrasound-assisted extraction, response surface method, anti-oxidation, gallnut tannin