Title
Impact of ultrasound pretreatment on whey protein hydrolysis by vegetable proteases
Author
Lucía Abadía-García, Eduardo Castaño-Tostado, Lech Ozimek, Sergio Romero-Gómez, César Ozuna, Silvia L. Amaya-Llano
Year
2016
Journal
Innovative Food Science & Emerging Technologies
Abstract
The ultrasound treatment on whey protein before enzymatic hydrolysis using vegetable proteases was studied. Ultrasound density, temperature, and pretreatment time effects were evaluated on enzymatic degree of hydrolysis, release of Angiotensin I-Converting Enzyme (ACE) inhibitors, and antioxidant activity of the hydrolysates generated. In addition, thermal properties as measured by Differential Scanning Calorimetry (DSC) and changes in secondary structure by circular dichroism (CD) were measured. The results showed that ultrasound density was the only factor that exerted a significant effect on proteolysis increasing the ACE inhibition by 13% and a 95% reduction of hydrolysis time in bromelain hydrolysates, but did not improve the ACE inhibition on papain hydrolysates. Observed changes in denaturation enthalpy (ΔH), reduction of reactive thiol groups, and changes in secondary structure suggest protein rearrangements and aggregate formation. The effect of ultrasound on the whey protein structure produced changes increasing the bioactivity of hydrolysates that could enhance the enzymatic hydrolysis process.
Instrument
J-720
Keywords
Circular dichroism, Secondary structure, Aggregation, Biochemistry