Optimization of Corn Resistant Starch Preparation by Dual Enzymatic Modification Using Response Surface Methodology...

Area of Science:

• Food Science
• Biochemistry
• Material Science

Background:

• Resistant starch (RS) offers health benefits but its low content in native starches limits applications.
• Enzymatic modification presents a promising strategy to increase RS content in starches.
• Corn starch is a widely available and cost-effective source for modification.

Purpose of the Study:

• To optimize dual enzyme modification of corn starch using thermostable α-amylase and pullulanase to enhance resistant starch (RS) content.
• To investigate the structural and property changes in corn starch after dual enzyme pretreatment.
• To determine the optimal conditions for maximizing RS yield through enzymatic hydrolysis.

Main Methods:

• Corn starch was dually modified using thermostable α-amylase and pullulanase.
• Response Surface Methodology (RSM) was employed to optimize pretreatment conditions, including starch concentration, enzyme dosages, and hydrolysis duration.
• Scanning Electron Microscopy (SEM) and Differential Scanning Calorimetry (DSC) were used to analyze structural alterations.

Main Results:

• Optimal pretreatment conditions were identified as 15% starch liquid, 3 U/g thermostable α-amylase, 35 min hydrolysis, and 8 U/g pullulanase.
• The maximum RS content achieved was 10.75%, a significant increase compared to native corn starch.
• Enzyme-modified starch exhibited a decreased degree of polymerization and showed distinct structural changes like pores and cracks under SEM.

Conclusions:

• Dual enzyme modification using thermostable α-amylase and pullulanase is an effective strategy for significantly enhancing the resistant starch content of corn starch.
• The optimized process yields a substantially higher RS content than native corn starch.
• Structural modifications observed via SEM and DSC confirm the impact of dual enzyme treatment on corn starch properties.