Kim Gap-Don, Ryu Youn-Chul, Jeong Jin-Yeon, Yang Han-Sul, Joo Seon-Tea
Division of Biotechnology, College of Applied Life Sciences, Jeju National University, Jeju 690-701, Republic of Korea.
J Anim Sci. 2013 Nov;91(11):5525-34. doi: 10.2527/jas.2013-6614. Epub 2013 Aug 29.
A total of six fiber types, including four pure types (type I, IIA, IIX, and IIB) and two hybrid types (type IIAX and IIXB), were classified according to the expression of myosin heavy chain (MHC) isoforms by immunohistochemistry with MHC specific monoclonal antibodies. The comparison of the muscle fiber characteristics and pork quality between pork quality groups (DFD: dark, firm, and dry; PSE: pale, soft, and exudative; RFN: reddish pink, firm, and nonexudative; and RSE: reddish pink, soft, and exudative) classified by muscle pH, drip loss, and lightness was conducted and the relationship of myofiber characteristics to pork quality was investigated. The DFD group had the highest value of IIAX fiber density (P<0.05). The DFD group also showed the greatest fiber relative area of type I, IIA, and IIAX (P<0.05) whereas there were no significant differences in area composition for types I, IIA, and IIAX among the other groups including PSE, RFN, and RSE (P>0.05). The DFD group had the highest cross-sectional area (CSA) in types I, IIA, and IIX among the groups. The increase in density of type IIAX was related with the higher pH and the lower hue and drip loss. An increase in the fiber number composition of hybrid type IIXB increased the lightness and cooking loss and decreased sarcoplasmic protein solubility (SPS). Regarding fiber relative area, pure type I and IIA and hybrid type IIAX were greater in the DFD group and had lower lightness and drip loss. Hybrid type IIAX influences the desirability of the pork due to its association with low lightness and high pH and water-holding capacity (WHC). In contrast, type IIXB was related to poor quality pork, including pale color, low WHC in cooked meat, and low SPS.
通过使用肌球蛋白重链（MHC）特异性单克隆抗体进行免疫组织化学，根据MHC同工型的表达，共分类出六种纤维类型，包括四种纯合类型（I型、IIA型、IIX型和IIB型）和两种杂合类型（IIAX型和IIXB型）。对根据肌肉pH值、滴水损失和亮度分类的猪肉品质组（DFD：暗、硬、干；PSE：苍白、柔软、渗出；RFN：微红、硬、不渗出；以及RSE：微红、柔软、渗出）之间的肌纤维特征和猪肉品质进行了比较，并研究了肌纤维特征与猪肉品质的关系。DFD组的IIAX纤维密度最高（P<0.05）。DFD组还显示出I型、IIA型和IIAX型的纤维相对面积最大（P<0.05），而在包括PSE、RFN和RSE在内的其他组中，I型、IIA型和IIAX型的面积组成没有显著差异（P>0.05）。DFD组在各类型中，I型、IIA型和IIX型的横截面积（CSA）最大。IIAX型密度的增加与较高的pH值、较低的色泽和滴水损失有关。杂合型IIXB纤维数量组成的增加会提高亮度和烹饪损失，并降低肌浆蛋白溶解度（SPS）。关于纤维相对面积，DFD组中纯合的I型和IIA型以及杂合的IIAX型更大，且亮度和滴水损失较低。杂合型IIAX由于与低亮度、高pH值和持水能力（WHC）相关，影响猪肉的品质。相比之下，IIXB型与劣质猪肉有关，包括颜色苍白、熟肉中WHC低和SPS低。
