Water transfer analysis in pork meat supported by NMR imaging

Area of Science:

• Food Science
• Biophysics
• Materials Science

Background:

• Understanding water transport in muscle foods is crucial for predicting drying behavior and optimizing food processing.
• Pork semi-membranosus muscle exhibits complex internal structures influencing moisture diffusion.

Purpose of the Study:

• To investigate the isothermal and unidirectional drying of pork semi-membranosus muscle.
• To quantify the effective water diffusivity (D) as a function of moisture content (X) and its dependence on lipid content, temperature, and fiber direction.

Main Methods:

• Utilized Nuclear Magnetic Resonance (NMR) proton density imaging to capture 2D moisture profiles during drying.
• Calibrated transversal relaxation time T(2) to determine moisture content from NMR signal amplitude.
• Applied the Boltzman transformation to calculate effective water diffusivity (D) without assuming a D=f(X) relationship.

Main Results:

• Effective water diffusivity (D) decreased significantly with decreasing moisture content (X) in all samples.
• Increased lipid content led to a substantial reduction in effective water diffusivity.
• Temperature (12-20 °C) and fiber direction showed negligible effects on water diffusivity, likely due to sample composition variability.

Conclusions:

• Lipid content is a primary factor limiting water diffusion during pork drying.
• NMR imaging provides valuable insights into spatial moisture distribution and water transport dynamics in muscle foods.
• The findings contribute to optimizing drying processes for meat products, impacting texture and shelf-life.