Pea protein is a type of plant protein that mainly used because of its low cost, wide availability and unique composition (globulin (70-80%) and albumins (10-20%)). In this study, the impact of enzymatic hydrolysis by Trypsin on the surface charge and size (hydrodynamic radius) of pea protein isolate (PPI) and its hydrolysates (HPPI) as a function of pH was investigated. The ratio of enzyme to the substrate (E/S) was 1:250 whereas the hydrolysis time was 60 minutes. The enzymatic hydrolysis was found to improve solubility, leading to a reduction in isoelectric point(PI) of pea protein isolate. The change in zeta potential and particle size was examined by Zeta Sizer as a function of pH. It was observed that the surface charge of PPI was decreased below pI whereas increased above pI of PPI after hydrolysis. For instance, the surface charge of pea protein isolate decreased from +30 mV to +15 mV at pH increase and then increased from -20 mV to -25 mV at pH might promote after hydrolysis. The size (hydrodynamic radius) was maximum at surface charge is zero for both PPI and HPPI. It was concluded that the increase in hydrophobic attraction and the decrease in intermicellar repulsion might support the growth in aggregate size of PPI after hydrolysis.
Anahtar Kelimeler: Hydrolysis, Pea Protein Isolate, Surface Charge, Size
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