Investigation of Quality Changes in Beef During Thermal Processing Using Nuclear Magnetic Resonance

Different water states, content levels, mobility, and migration characteristics significantly influence meat quality attributes such as water-holding capacity, tenderness, juiciness, physical parameters, and shelf life. Leveraging this principle, nuclear magnetic resonance (NMR) technology enables rapid, non-destructive, and real-time analysis of meat quality changes.

Water Migration During High-Temperature Braising of Beef

Early braising stage (60–90 min): High temperatures disrupt the protein structure, causing water to migrate from inside the myofibrils to the extracellular space. Immobile water decreases while free water increases. Heat-induced contraction of muscle fibers strengthens the binding of intracellular water, reducing T₂₂ mobility. Simultaneously, damage to the protein matrix decreases water-holding capacity and increases T₂₃ mobility. Some bound water is released due to thermal effects, lowering its content.

Mid braising stage (90–180 min): As internal water is gradually lost, osmotic gradients increase. Around 150 minutes, a “reverse absorption” phenomenon occurs where water migrates back into the cells. Free water decreases while immobile water increases. The intensified concentration gradient triggers frequent water exchange across compartments. Once a balance is reached, the mobility of various water states stabilizes.

T1-Weighted Imaging During Beef Braising

In T1-weighted images, the net-like structure represents intramuscular fat, while darker regions reflect muscle tissue. As braising time increases, fat begins to dissolve, making the fat-rich areas appear brighter. Eventually, fat is rendered and replaced by water, brightening the overall image and blurring the net-like texture.
NMR relaxation analysis captures the transformation and migration of different water states, providing insight into quality changes and guiding process optimization.

NMR imaging visually reveals water and fat migration, offering a cutting-edge analytical approach for meat science and food processing research.