OBJECTIVE To explore the effects of restrictive enzymatic modification on the structural and functional characteristics of plum seed protein, using the plum seed protein isolates as the research object.
METHODS The alcalase was used to hydrolyze plum seed protein isolates. The effects of hydrolysis time on subunits, secondary and tertiary structure, solubility, emulsifying properties, surface hydrophobicity, ζ-potential and thermal stability of protein were evaluated.
RESULTS After enzymatic modification of plum seed protein isolates, the solubility, emulsifying activity index, emulsifying stability and surface hydrophobicity were improved by 156%, 135%, 696%, and 182%, respectively. The improvement in functional properties was attributed to the release of small molecular peptide, the increase of random coil and surface charge and unfolding of molecule induced by enzymatic modification. However, the improvement in functional properties was also dependent on the degree of hydrolysis. The excessive hydrolysis (the degree of hydrolysis > 6.3) could induce the aggregation of protein which led to a decrease in functional properties. In addition, the treatment of limited hydrolysis also reduced the thermal stability of plum seed protein isolates.
CONCLUSION The functional properties of plum seed protein isolates can be improved by controlling the degree of hydrolysis.
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