Ultrasound Pretreatment as an Useful Tool to Enhance Egg White Protein Hydrolysis: Kinetics, Reaction Model, and Thermodinamics.
The impact of ultrasound waves generated by probe-type sonicator and ultrasound cleaning bath on egg white protein susceptibility to hydrolysis by alcalase compared to both thermal pretreatment and conventional enzymatic hydrolysis was quantitatively investigated. A series of hydrolytic reactions was carried out in a stirred tank reactor at different substrate concentrations, enzyme concentrations, and temperatures using untreated, and pretreated egg white proteins (EWPs). The kinetic model based on substrate inhibition and second-order enzyme deactivation successfully predicts the experimental behavior providing an effective tool for comparison and optimization. The ultrasound pretreatments appear to greatly improve the enzymatic hydrolysis of EWPs under different conditions when compare to other methods. The apparent reaction rate constants for proteolysis (k2) are 0.009, 0.011, 0.053, and 0.045 min-1for untreated EWPs, and those pretreated with heat, probe-type sonicator, and ultrasound cleaning bath technologies, respectively. The ultrasound pretreatment also decreases hydrolysis activation (Ea) and enzyme deactivation (Ed) energy, enthalpy (ΔH), and entropy (ΔS) of activation and for the probe-type sonication this decrease is 61.7%, 61.6%, 63.6%, and 32.2%, respectively, but ultrasound has little change in Gibbs free energy value in the temperature range of 318 to 338 K. The content of sulfhydryl groups and ζ potential show a significant increase (P < 0.05) for both applied ultrasound pretreatments and the reduction of particle size distribution are achieved, providing some evidence that the ultrasound causes EWP structural changes affecting the proteolysis rate.
Dept. of Biochemical Engineering and Biotechnology, Faculty of Technology and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000, Belgrade, Republic of Serbia.
Jelena R
JR
Jovanović
Dept. of Biochemical Engineering and Biotechnology, Faculty of Technology and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000, Belgrade, Republic of Serbia.
Andrea B
AB
Stefanović
Innovation Center, Faculty of Technology and Metallurgy, Karnegijeva 4, 11000, Belgrade, Republic of Serbia.
Nataša Ž
NŽ
Šekuljica
Dept. of Biochemical Engineering and Biotechnology, Faculty of Technology and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000, Belgrade, Republic of Serbia.
Sonja M Jakovetić
SMJ
Tanasković
Dept. of General Technical Sciencies, Faculty of Technology and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000, Belgrade, Republic of Serbia.
Marina B
MB
Dojčinović
Dept. of Chemical Engineering, Faculty of Technology and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000, Belgrade, Republic of Serbia.
Branko M
BM
Bugarski
Dept. of Biochemical Engineering and Biotechnology, Faculty of Technology and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000, Belgrade, Republic of Serbia.
Zorica D
ZD
Knežević-Jugović
EWPs; enzymatic hydrolysis; kinetic model; particle characteristics; ultrasound pretreatment