Equivalent dose methodology for activity-based comparisons of protease performance during byproduct protein hydrolysis.

An experimental methodology to compare the hydrolysis performance of different proteases based on equivalent doses was proposed and validated. The specific activities were quantified via nonlinear fitting of the logarithmic equation to the reaction progress plot. The obtained kinetic constants were plotted against the protease dose to calculate the specific activities from the slope, resulting in 4214, 1127, 10,277 and 3139 U/g for Alcalase, Flavourzyme, Neutrase and Protamex, respectively. The hydrolysis performances were evaluated using equivalent doses of proteases during the hydrolysis of 50 %(/w) salmon frame at 50 °C and pH 7.5. Higher degrees of hydrolysis were obtained with Flavourzyme (177 mM and 12 %), whereas greater protein recovery was obtained with Alcalase (55 %). Alcalase was the most cost-efficient protease with 4.3 kg of extracted protein per USD. The presented strategy is an affordable methodology that can be applied to different byproduct-protease systems.