Mechanistic insights into structural reorganization and quality formation of starch coated pork tenderloin under mechanical pounding.

Abstract

Pork tenderloin slices subjected to graded pounding were used to clarify how mechanical treatment influences structural reorganization, quality formation, and in vitro digestibility. Moderate pounding, particularly for 120 s, reduced hardness and chewiness while improving water-holding capacity and tenderness. Low-field nuclear magnetic resonance indicated redistribution of water from tightly bound to immobilized fractions, with prolonged relaxation times, suggesting a loosened myofibrillar matrix. Differential scanning calorimetry and vibrational spectroscopy showed reduced protein denaturation temperatures and enthalpy, accompanied by a 36.7% decrease in α-helix content, a 119.7% increase in β-turn content, and surface hydrophobicity increasing to about 67%. Electrophoretic analysis suggested limited protein fragmentation and aggregation. During simulated digestion, moderately pounded samples exhibited higher protein solubility and faster hydrolysis, with overall digestibility increasing to approximately 90%, compared with about 83% in the control. These results provide structural insight into quality improvement and digestibility enhancement in mechanically treated pork tenderloin.