Enzymolysis kinetics and structural-functional properties of high-intensity ultrasound-assisted alkali pretreatment ovalbumin

Abstract

This research investigated the enzymolysis kinetics of high-intensity ultrasound (HIU)-assisted alkali pretreatment Ovalbumin (OVA) through using Alcalase, and its structural and functional properties. The structural characteristics of OVA were performed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), surface hydrophobicity, Fourier Transform Infrared, and differential scanning calorimetry. SDS-PAGE analysis indicated that the pretreatment sample showed proportion of lower molecular mass components (14.3-20.1 kDa). There was an increase in the intensity of fluorescence spectrum and changes in functional groups after the pretreatment on OVA compared with the control (without treatment), which might be the reason for the significantly enhancing efficiency of the enzymatic hydrolysis. The thermal denaturation temperature of enzymatic hydrolysis of OVA after pretreatment was 95.1°C, which was 17.5°C higher than that of control. As compared to OVA (control), the enzymatic hydrolysis with HIU-assisted alkali pretreatment was found to significantly improve protein solubility, emulsifying properties, foaming ability (FA) and foam stability, oil, and water absorption capacity (WAC). Especially emulsifying activity index, FA, WAC, and oil absorption capacity were increased by 228.7%, 88.5%, 102.6%, and 67.4%, respectively (P< 0.05). A simplified kinetic equation for the enzymolysis model was deduced to successfully describe the enzymatic hydrolysis of pretreated OVA. The results proved the effects of the pretreatment on the substrate enhanced the enzymolysis process and this influence had relation to the structure changes. Furthermore, the enzymatic hydrolysis process for other proteins demonstrated the applicability of the model.

Impact of different ultrasound-assisted processes for preparation of collagen hydrolysates from Asian bullfrog skin on characteristics and antioxidative properties

“…Gly is the predominant amino acid in collagen, contributing to intramolecular hydrogen bonding perpendicular to the helical axis, thus stabilizing its structure [38] . All tested samples contained significant amounts of hydrophobic amino acids, including Ala, Leu, Met, Phe, Pro, Thr, and Val, which have been reported in antioxidative peptides [11] , [24] . Previous studies have reported that the higher hydrophobic amino acids in proteins and their hydrolysates govern the higher antioxidative activities [24] , [31] .…”

“…Based on the amino acid composition in the present study, the control had the highest hydrophobic amino acid content (9.76 %), followed by UP-20 (9.26 %) and US-30 (9.11 %), which was not in accordance with their antioxidative activities. The antioxidative properties of peptides are known to be greatly influenced not only by their amino acid composition or peptide size, but also by the molecular configuration that determines peptide folding behavior and exposure of hydrophobic patches on their surface [11] , [34] , [39] . The results indicated that the different amino acid compositions of CHs might govern changes in the secondary structure of peptides induced by UAP, which was more likely related to the variation in their antioxidative activity [40] .…”

“…Ultrasound has been used to improve protein properties by enhancing enzyme activity, extracting components from materials, and modifying the availability and functional properties of several proteins [9] . Recently, UAP has been used as a pre-treatment (UP) in conjugation with enzymatic hydrolysis to enhance production efficiency and protein characteristics [10] , [11] , [12] . Furthermore, UAP has been successively used as a simultaneous treatment (US) with enzymatic hydrolysis, in which the combined effect could enhance the enzyme activity and favor the penetration of enzyme into the sample matrix [10] , [13] .…”

Effect of microwave freeze drying on moisture migration and gel characteristics of egg white protein

“…Protein can be hydrolyzed by protease under mild conditions in order to achieve the purpose of protein modification, without reducing the nutrition of food value, which can even increase the functionality of the protein (Liang et al, 2020). Liu et al found that protein side‐chain reaction in chemical modification can preserve or alter the electrostatic charge and enhance the functional properties of proteins (Liu, Hao, et al, 2020). Katekhong and Charoenrein (2017) studied the effect of SD temperature on the physical properties, solubility, and gelling properties of egg white protein powder and determined the relationship between the storage stability of the sample, temperature, and time, providing a basis for the production and storage of protein powder.…”

Effects of synergistic modification with enzymatic hydrolysis and phosphorylation on functional and structural properties of ovalbumin

“…At present, the methods for modifying OVA mainly include physical, chemical, and enzymatic methods, by changing the amino acid composition, sequence of ovalbumin, the size of the protein molecule, the number of hydrophobic groups, and the surface electrostatic charge etc. (An et al, 2014;Liu, Hao, et al, 2020).…”