浸渍冻结对凡纳滨对虾冻藏过程中肌肉组织的影响

Effect of Immersion Chilling and Freezing on Muscle Structure of Litopenaeus vannamei during Frozen Storage

摘要:

本文以肌纤维轮廓、细胞间隙、肌丝、肌节以及肌纤维间隙等为指标，研究浸渍冻结和静止空气冻结对凡纳滨对虾冻藏过程中肌肉组织结构的影响。结果发现，浸渍冻结对虾的肌纤维排列更加致密，形成的冰晶间隙更加细小，分布均匀，肌原纤维直径变短的程度比静止空气冻结的小；而静止空气冻结的肌纤维排列疏松，形成的冰晶间隙宽大。随着贮藏时间的增加，浸渍冻结对虾的冰晶逐渐增大，间隙逐渐变大，细胞核也逐渐分解变少。冻藏90 d后，静止空气冻结对虾中很难发现细胞核的存在，肌丝结构大部分消失，明暗带难分辨，肌节长度变短程度严重，肌节消失，且没有完整结构的线粒体。但是浸渍冻结对虾中肌丝结构及明暗带依然存在，肌节长度变短程度比静止空气冻结的小，部分线粒体结构完整。结果表明，浸渍冻结更有利于对虾的肌肉结构的保持，能更好地保持对虾的品质。

Abstract:

Changes in fiber profile, intercellular gaps, myofilament, sarcomere, and intermyofibrillar space during frozen storage of shrimp, Litopenaeus vannamei was investigated to determine the effects of immersion chilling and freezing (ICF) as well as refrigerator freezing (RF) on shrimp musculature. The results indicated that muscle fiber of ICF shrimp was tighter and the intercellular ice crystals were smaller and well-distributed, whereas that of RF shrimp was loose, and the intercellular ice crystals were larger and wider. The myofibril diameter of ICF shrimp were shorter than that of RF shrimp. As the storage period increased, the ice crystals in the ICF shrimp grew larger, while cell nuclei gradually decreased. After storing for 90 d, cell nuclei could not be found in tissue slices of RF shrimp, myofilament had largely disappeared, the thick and thin filaments were blurred, the length of the sarcomere was severely shortened, and sarcomere structures had disappeared. Moreover, the complete structure of mitochondria in the tissue of RF shrimp could hardly be found. However, the myofilament structures, and the thick and thin filaments still existed in ICF shrimp. The degree of shortening in myofilament lengths was smaller than that in RF shrimp, while some mitochondrial structures remained intact in the tissues of ICF shrimp. In summary, ICF appeared to be more beneficial to maintain the quality of shrimp during frozen storage.