Properties of protease-treated maize starches

Area of Science:

• Food Science
• Biochemistry
• Materials Science

Background:

• Maize starch is a key industrial ingredient.
• Protease treatment is explored for modifying starch properties.

Purpose of the Study:

• To evaluate the impact of protease treatment on maize starch composition and properties.
• To assess potential modifications to starch structure and functionality.

Main Methods:

• Protease (Promod 25P) treatment of waxy, normal, and amylomaize starches.
• Analysis of protein, lipid, and amylose content.
• Scanning electron microscopy (SEM) for granule surface morphology.
• Coulter Counter Multisizer for granule dimensions.
• Differential scanning calorimetry (DSC) for gelatinization.
• Swelling factor and alpha-glucan leaching measurements.

Main Results:

• Protease treatment significantly reduced starch protein (41-37%) and lipid (45-40%) content.
• SEM revealed surface pitting, but granule dimensions remained largely unchanged.
• Normal maize starch showed a decrease in amylose content (30.7-26.0%).
• Gelatinization parameters and swelling factors were minimally affected.
• Alpha-glucan leaching increased significantly, particularly in waxy maize starch (3.8-fold).

Conclusions:

• Protease treatment is effective for maize starch purification, reducing protein and lipid content.
• Surface modifications and altered leaching properties were observed.
• Commercial protease preparations require amylase content control to prevent unwanted starch modifications during industrial processing.