The Impact of High-Intensity Ultrasound-Assisted Extraction on the Structural and Functional Properties of Hempseed Protein Isolate (HPI)

Abstract

Hempseed protein has become a promising candidate as a future alternative protein source due to its high nutritional value. In the current study, hempseed protein isolate (HPI) was obtained using ultrasonic-assisted extraction with the aim to improve the functionality of HPI via protein structure modification. The solubility of HPI could be improved twofold under 20 kHz ultrasound processing compared to conventional alkaline extraction-isoelectric point precipitation. The protein solubility was gradually enhanced as the ultrasonic power improved, whereas excessive ultrasound intensity would cause a decline in protein solubility. Ultrasonic processing was found to have beneficial effects on the other functionalities of the extracted HPI, such as emulsifying and foaming properties. This improvement can be ascribed to the physical effects of acoustic cavitation that changed the secondary and tertiary structures of the protein to enhance surface hydrophobicity and decrease the particle size of the extracted protein aggregates. In addition, more available thiols were observed in US-treated samples, which could be another reason for improved functionality. However, the results of this study also revealed that prolonged high-power ultrasound exposure may eventually have a detrimental impact on HPI functional properties due to protein aggregation. Overall, this study suggests that high intensity ultrasound can enhance the functionality of HPI, which may ultimately improve its value in HPI-based food products.

Enhancing silkworm protein yield, extraction efficiency, structure, functionality, and antioxidant activity using ultrasound‐, microwave‐, and freeze–thaw‐assisted methods

“…For example, ice crystal growth during freezing 32 could have opened the silkworm protein structure, thus exposing buried SH groups during freeze–thaw cycles. A similar effect in UAE samples could have occurred due to the high shear forces and turbulent flow created by ultrasound waves 33 . Finally, microwave treatment in MAE samples could have exposed internal SH groups by altering protein molecular conformation and expanding polypeptide chains, and formed new SH groups by breaking the disulfide bonds 11 .…”

“…A similar effect in UAE samples could have occurred due to the high shear forces and turbulent flow created by ultrasound waves. 33 Finally, microwave treatment in MAE samples could have exposed internal SH groups by altering protein molecular conformation and expanding polypeptide chains, and formed new SH groups by breaking the disulfide bonds. 11 These may indicate FTAE, UAE, and MAE-induced protein structural changes by unfolding the protein molecules and exposing the SH groups.…”

Alternative methods for RuBisCO extraction from sugar beet waste: A comparative approach of ultrasound and high voltage electrical discharge

“…When comparing these two alternative methods, the US method proved to be by far the more efficient method for protein extraction. Higher protein yield in US samples can be attributed to the high shear and mass transfer effects caused by acoustic cavitation [68] . This is consistent with previous studies with the Lowry method for protein quantification.…”

The Evolution of Sonochemistry: From the Beginnings to Novel Applications

“…Low‐frequency ultrasound (20 kHz) is employed in food processing to prevent aggregation, improve solubility, increase extraction yield, and enhance protein functionality (Table 1). [73] …”