Abstract:The general objective of the present work was to assess the applicability of pressure-transform tumbling curing assisted by ultrasound (PTU) technique for improving the curing effect in duck processing. For this purpose, the effect of PTU on duck protein denaturation, structure changes of myofibrillar proteins and moisture distribution was investigated and was compared with those of obtained with raw duck (untreatment) or vacuum tumbling (VT). Indexes such as degradation of protein, changes of protein structures and water states of different treatment samples were analyzed. Results showed that with the increasement of PTU treatment time, the amount of macromolecular myofibrillar proteins degraded, the amount of MHC (myosin heavy chain), desmin, troponin T, tropomyosin were decreased gradually. At the same time, some small molecule protein fragments appeared. Raman spectroscopy was used to analyze the changes of protein spatial structures. The results showed that the proportion of α-helix was reduced greatly (P<0.05), and the amount of β-sheet, β-turn and random coil were increased (P<0.05) after PTU treatment. The LF-NMR data indicated that the position of the component T21 and T22 were clearly prolonged relaxation times by tumbling. Moreover,the proportion of peak area of T21 and T22 were significantly increased (P<0.05), especially for PTU treatment, which indicated that the water molecules combined with protein more tightly and parts of free water turned into immobilized water. The results can provide the theoretic basis for the PTU technology in the meat industry and related equipment design.