Dynamic Viscoelastic Behavior of Maize Kernel: Application of Frequency-Temperature Superposition

Area of Science:

• Food Science
• Materials Science
• Rheology

Background:

• Maize kernel properties are influenced by drying methods.
• Understanding these properties is crucial for storage and processing.

Purpose of the Study:

• To compare the rheological properties of maize kernels dried using natural drying (ND) and combined hot air- and vacuum-drying (HAVD).
• To analyze the sensitivity and applicability of modified Cole-Cole (MCC) analysis and frequency-temperature superposition (FTS) for characterizing dried maize kernels.

Main Methods:

• Maize kernels were subjected to ND and HAVD (75 °C).
• Frequency sweep tests, MCC analysis, and FTS were performed.
• Elastic and viscous properties were measured.

Main Results:

• ND-treated kernels exhibited higher elastic and viscous properties compared to HAVD-treated kernels.
• MCC analysis revealed curvature for HAVD 75 °C kernels, suggesting heterogeneity and potential FTS failure.
• HAVD 75 °C treated kernels showed thermorheologically simple behavior and an expanded frequency scale (up to 70,000 Hz).
• Relaxation processes in HAVD 75 °C kernels were linked to molecular subunits.

Conclusions:

• Drying methods significantly impact maize kernel rheological properties.
• MCC analysis is a more sensitive method than FTS for characterizing heterogeneous maize kernels.
• HAVD at 75 °C yields maize kernels with specific thermorheological characteristics suitable for further processing and storage applications.