Effects of multifrequency ultrasound pretreatment on the enzymolysis, ACE inhibitory activity, and the structure characterization of rapeseed protein
Asif Wali, Haile Ma, Rana Muhammad Aadil, Cunshan Zhou, Muhammad Tayyab Rashid, Xiao Liu
Journal of Food Processing and Preservation
In this study, the effects of multifrequency ultrasound pretreatment with various frequency modes on rapeseed protein enzymolysis and its mechanism were studied. Following processing parameters, including substrate concentration, enzyme dosage, power density, pretreatment time and initial temperature on the degree of hydrolysis (DH) and angiotensin-I-converting enzyme (ACE) inhibitory activities of the hydrolysates, were evaluated using single-factorial experiments. The structural characteristics were analyzed using circular dichroism spectra and scanning electron microscopy. The results showed that during the screening of multifrequency ultrasonic pretreatment, combined fixed frequency 24/28 kHz significantly (p < .05) improved the DH and ACE inhibitory activity over the control. The experimental verification test results revealed that the processing factors that were studied had a significant effect on the DH and ACE inhibitory activity, which increased by 19.12 and 35.08% over the control, respectively. The molecular conformation of rapeseed protein indicated that sonication had destroyed the microstructure and increased surface area.
Circular dichroism, Secondary structure, Protein folding, Biochemistry, Food science