Kinetics of silkworm pupae protein extraction at different ultrasonic frequency and temperature: Effects on physicochemical properties, functional properties and oxidation resistance

The purpose of this study was to determine the effects of different ultrasonic frequencies (22 kHz, 28 kHz, 40 kHz, 22/28 kHz, 22/40 kHz, 28/40 kHz, 22/28/40 kHz), and temperatures (20 ℃, 30 ℃, 40 ℃, 50 ℃) on the kinetics of protein extraction from silkworm chrysalis. And the effect of ultrasound on the physicochemical, functional properties, and biological activity of silkworm pupa protein. The extraction kinetics of silkworm pupa protein was studied based on logarithmic, second-order, Peleg's, and power-law models. The highest correlation coefficient of the second-order rate model is 0.999, so the second-order rate model is more suitable for the extraction of silkworm pupa protein. After ultrasonic treatment, the secondary and tertiary structures of silkworm pupa protein changed, α-Helix decreased significantly and fluorescence increased, surface roughness increased. The silkworm pupa protein of double frequency (28/40 kHz) ultrasound has the highest emulsifying performance and lotion stability, while the silkworm pupa protein of triple frequency (22/28/40 kHz) ultrasound has the highest solubility and antioxidant performance. This study provides a theoretical basis for the application of multifrequency ultrasound technology in protein extraction and modification of silkworm chrysalis. © 2022 Elsevier Ltd