Mechanism of low-frequency and high-frequency ultrasound-induced inactivation of soy trypsin inhibitors

Yue Wu; Wu Li; Gregory J O Martin; Muthupandian Ashokkumar

doi:10.1016/j.foodchem.2021.130057

Mechanism of low-frequency and high-frequency ultrasound-induced inactivation of soy trypsin inhibitors

Food Chem. 2021 Oct 30:360:130057. doi: 10.1016/j.foodchem.2021.130057. Epub 2021 May 11.

Authors

Yue Wu¹, Wu Li¹, Gregory J O Martin², Muthupandian Ashokkumar³

Affiliations

¹ Sonochemistry Group, School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
² Algal Processing Group, Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia. Electronic address: [email protected].
³ Algal Processing Group, Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia. Electronic address: [email protected].

PMID: 34029924
DOI: 10.1016/j.foodchem.2021.130057

Abstract

In this study, the effect of ultrasonic frequency and power on the inactivation of soy trypsin inhibitors (TIs) was investigated to explore the ultrasound-induced inactivation mechanism. It was observed that 20 kHz and 355 kHz ultrasound have better inactivation efficiency than 1056 kHz. First-order rate constants for the inactivation process were obtained, which increased with increasing ultrasonic power at both 20 kHz and 355 kHz. For 20 kHz ultrasound, the formation of TI aggregates resulting from the physical effects of acoustic cavitation decreased the interactions between the active sites of TIs and trypsin, thus reducing the TI activity. For 355 kHz ultrasound, most of the methionine in the TIs was oxidised within 5 mins, resulting in a faster reduction of TI activity. Subsequent aggregation of TIs resulted in further TI inactivation. SDS-PAGE showed that neither disulphide bonds nor CC coupling were involved in the formation of aggregates.

Keywords: High-frequency ultrasound; Inactivation; Low-frequency ultrasound; Oxidation; Soy trypsin inhibitors.

MeSH terms

Catalytic Domain
Glycine max / metabolism*
Kinetics
Particle Size
Plant Proteins / chemistry*
Plant Proteins / metabolism
Sonication*
Trypsin Inhibitors / chemistry*
Trypsin Inhibitors / metabolism

Substances

Plant Proteins
Trypsin Inhibitors