Improvement of the production of pequi almond (Caryocar brasiliense Camb.) protein hydrolysates through ultrasound-assisted enzymolysis: Impact on hydrolysis kinetics, structure and functional properties of hydrolysates

This study investigated the kinetics of ultrasound (US)-assisted hydrolysis of pequi almond protein (PAP) and the conformational and multifunctional characteristics of the hydrolysates. The US-assisted enzymolysis of PAP using Alcalase (R) was conducted in a US bath (25 kHz, 38 W/L) for 180 min at 60 degrees C and pH 7.5. The results showed an increase in the rate of proteolysis by 11.3 %, leading to a higher final degree of hydrolysis (25.2 %) and a greater concentration of TCA-soluble proteins after 45 min and 180 min (29 % and 8 %, respectively). Both conventional and US-assisted hydrolysis led to the breakdown of the protein structure, forming low molecular weight peptides (<15 kDa). However, US-assisted hydrolysis demonstrated greater fragmentation of the PAP surface, enhancing enzymatic efficacy. Intrinsic fluorescence and UV spectroscopy indicated increased exposure of hydrophobic groups throughout hydrolysis, and FTIR spectroscopy revealed changes in the amide bands, suggesting structural transitions in the protein. Finally, the hydrolysates obtained from the USassisted reaction showed higher solubility (<27 % at pH 6.0), foaming capacity (<82 % at pH 6.0), and antioxidant activity (<40 %). Therefore, these results indicate the potential of the US to improve the performance of Alcalase (R) in the hydrolysis of PAP, producing compounds of industrial interest.