Physicochemical and chemical properties of mung bean protein isolate affected by the isolation procedure

The effects of different mung bean protein isolation methods on the chemical composition, the physicochemical
properties, and selected antinutritional factors of mung bean protein isolates were investigated. Six protein
isolates were prepared by isoelectric precipitation at different extraction pH levels (pH 8 and 9), by micellization,
and by hybrid isolation at varying salt concentrations (0.25 M, 0.50 M, 0.75 M). The extraction conditions
affected the amount of antinutritive compounds of the isolates. Compared to mung bean flour, micellization
reduced phytic acid content by approximately 48% and trypsin inhibitor activity by around 88%. The remaining
phytic acid concentration of the isolates influenced their re-solubility, particularly under acidic conditions. The
protein isolates exhibited significant differences in surface hydrophobicity and thermal characteristics, indicating
structural modifications caused by the extraction methods. Micellization and extraction at pH 8 were identified
as mildest isolation methods, as evidenced by the highest enthalpy values. SDS-PAGE analysis demonstrated an
enrichment of globulins and comparable protein profiles among the isolates, suggesting that the observed dif ferences arise from conformational changes rather than variations in protein composition. The product yield in
protein extraction from mung beans ranged from 8% to 19%, emphasizing the importance of enhancing overall
extraction efficiency or exploring the utilization of by-products obtained during the protein isolation process.