Superheated steam cooking improved meat quality: evidenced by water status and protein degradation

This study aimed to investigate the relationship among physicochemical quality, water status and protein degradation of pork samples during superheated steam (SHS) cooking. Pork samples were cooked with SHS (120, 150 and 180 ℃ and traditional steam (TS) to 40, 60 and 80 ℃. The results showed that SHS cooking at 150 and 180 ℃ significantly reduced the values of lightness (L*), yellowness (b*), cooking loss and increased the value of redness (a*). Moreover, SHS cooked samples had lower shear force, hardness and chewiness value than TS cooked samples, indicating a better mouth feel quality. Low-field nuclear magnetic resonance (LF-NMR) analysis results showed that relaxation time T₂₁, T₂₂ and T₂₃ increased with SHS temperature, T₂ (TS-cooked) < T₂ (SHS-cooked), SHS had higher P₂₂ values but lower P₂₃ values than TS. The secondary structure of pork protein cooked by TS tends to be loose than SHS, promoting more immobilized water into free water. Furthermore, SHS led to a low exposure of hydrogen bonds and hydrophobic bonds which reduced protein aggregation. The protein degradation and water status could explain the quality differences between SHS and TS cooked pork.