Characteristics of enzymolysis of silkworm pupa protein after tri-frequency ultrasonic pretreatment: kinetics, thermodynamics, structure and antioxidant changes

Shuangmei Ge; Chunyan He; Yichen Duan; Xiaotao Zhou; Jialong Lei; Xiangyun Tong; Libing Wang; Qiongying Wu; Junqiang Jia

doi:10.3389/fbioe.2023.1170676

Characteristics of enzymolysis of silkworm pupa protein after tri-frequency ultrasonic pretreatment: kinetics, thermodynamics, structure and antioxidant changes

Front Bioeng Biotechnol. 2023 Jun 23:11:1170676. doi: 10.3389/fbioe.2023.1170676. eCollection 2023.

Authors

Shuangmei Ge¹, Chunyan He¹, Yichen Duan¹, Xiaotao Zhou¹, Jialong Lei¹, Xiangyun Tong¹, Libing Wang¹, Qiongying Wu¹, Junqiang Jia²

Affiliations

¹ School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China.
² School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang, China.

Abstract

As a by-product of the sericulture industry, the utilization rate of silkworm pupa resources is currently not high. Proteins are converted into bioactive peptides through enzymatic hydrolysis. Not only can it solve the utilization problem, but it also creates more valuable nutritional additives. Silkworm pupa protein (SPP) was pretreated with tri-frequency ultrasonic (22/28/40 kHz). Effects of ultrasonic pretreatment on enzymolysis kinetics, enzymolysis thermodynamics, hydrolysate structure as well as hydrolysate antioxidant of SPP were investigated. Ultrasonic pretreatment significantly increased the hydrolysis efficiency, showing a 6.369% decrease in k _m and a 16.746% increase in k _A after ultrasonic action (p < 0.05). The SPP enzymolysis reaction followed a second-order rate kinetics model. Evaluation of enzymolysis thermodynamics revealed that Ultrasonic pretreatment markedly enhanced the SPP enzymolysis, leading to a 21.943% decrease in E _a. Besides, Ultrasonic pretreatment significantly increased SPP hydrolysate's surface hydrophobicity, thermal stability, crystallinity, and antioxidant activities (DPPH radical scavenging activity, Fe²⁺ chelation ability, and reducing power). This study indicated that tri-frequency ultrasonic pretreatment could be an efficient approach to enhancing the enzymolysis and improving the functional properties of SPP. Therefore, tri-frequency ultrasound technology can be applied industrially to enhance enzyme reaction process.

Keywords: antioxidant; dynamics; enzymolysis; protein; thermodynamics.

Grants and funding

This work was supported by the Jiangsu Agricultural Science and Technology Innovation Fund [CX(20)2029], the Postgraduate Research and Practice Innovation Program of Jiangsu Province (KYCX22_3862), and Jiangsu University Student Innovation and Entrepreneurship Training Program (202110289003Z).