冷冻及反复冻融期间猪背最长肌正常肉和PSE肉的品质比较

Quality Comparison of PSE Pork Longissimus Dorsi During Frozen Storage and Repeated Freeze-Thaw Cycles

摘要:

为了探究冷冻PSE肉（Pale, Soft, and Exudative, PSE）经冻融循环后的品质变化，为工业生产提供依据。本文探究了鲜肉、冷冻6个月及冻融循环过程中的正常肉和PSE肉的pH值、解冻失水率、新鲜度（挥发性盐基氮、酸度/氧化力系数）、肉色、质构特性的变化。研究发现反复冻融期间猪肉pH值下降，冻融第3次与第1次相比，正常肉的解冻失水率显著下降64.61%（P<0.05），而PSE肉仅下降27.62%（P<0.05）。冻融循环第4至6次时，PSE肉的剪切力、凝聚性、弹性与正常肉差异不显著（P>0.05）。综上表明，冷冻6个月和反复冻融给PSE肉品质造成影响。反复冻融4次PSE肉的嫩度明显提升，此时解冻失水率与正常肉相似，生产中可以根据实际条件适当调整PSE肉的解冻次数，为PSE肉产品开发及合理加工利用提供理论基础。

Abstract:

Quality changes of frozen Pale, Soft, and Exudative (PSE) pork after freeze-thaw cycles were investigated to provide a theoretical basis for industrial production. Changes in pH, thawing loss rate, freshness (total volatile basic nitrogen, acidity/oxidation-reduction potential coefficient), meat color and texture properties were determined in fresh pork, 6-month frozen pork, normal pork and PSE pork during freeze-thaw cycles. A decrease in the pH value of pork during repeated freeze-thaw cycles was observed. Compared with the first freeze-thaw cycle, the thawing loss rate of normal pork was significantly reduced by 64.61% (P<0.05) at the third cycle, while that of PSE pork was only reduced by 27.62% (P<0.05). No significant differences in shear force, cohesiveness and springiness between PSE pork and normal pork were observed from the 4th to the 6th freeze-thaw cycles (P>0.05). In conclusion, the quality of PSE pork was affected by 6-month freezing and repeated freeze-thaw cycles. The tenderness of PSE pork was significantly improved after 4 freeze-thaw cycles, and its thawing loss rate was found to be similar to that of normal pork. The number of freeze-thaw cycles for PSE pork could be appropriately adjusted according to practical production conditions, and a theoretical basis for the development and rational processing of PSE pork products was provided.