不同品种羊肉滴水损失与肌肉品质的关系

Effect of Drip Loss of Lamb from Different Varieties on the Meat Quality

研究不同滴水损失羊肉的微观结构和理化特性,分析蛋白质降解对羊肉滴水损失的影响,揭示羊肉滴水损失与肌肉品质的关系。选择3个山羊品种(波尔山羊、黄淮山羊、波尔×崂山白山羊)的最高、最低滴水损失的背最长肌样品各3块,分析宰后p H值、肉色、剪切力、微观结构、肌原纤维蛋白降解程度的差异。结果表明,低滴水损失组的宰后45 min样品的p H45 min显著高于高滴水损失组,而L*值与p H45 min相反(P<0.05);高滴水损失组的a*、b*、△E、剪切力值、肌节长度和TBARS值与低滴水损失组没有显著差异(P>0.05);低滴水损失组的肌节较为完整,肌细胞排列紧密,几乎没有缝隙;而高滴水损失率组部分肌节扭曲、变形,排列错乱,部分Z线偏离或断裂;高滴水损失组的肌节长度均低于低滴水损失组(P<0.05);高滴水损失组肌原纤维蛋白发生明显降解,蛋白质变性。总之,羊肉p H值下降导致蛋白质降解,影响蛋白质与水之间的相互作用,引起肌纤维结构的变化,肌肉收缩,造成高的滴水损失。

The effect of different drip loss on microstructure, physico-chemical properties and protein degradation of lamb was studied. By measuring of the drip loss, M. longissimus dorsi from 3 varieties（Boer goat, Huanghuai goat,Boer×Laoshan goat） were divided into high drip loss group and low drip loss group（n=3）. The meat quality parameters p H, color, shear force, microstructure characteristics and degradation of myofibrillar protein were investigated. The results were showed that p H45 minof low drip loss group was higher than high group, while the brightness opposite（P〈0.05）. a＊,b＊, △E, shear force, sarcomere length and thiobarbituric acid reactive substances（TBARS） were not different between both groups（P〉0.05）. The sarcomeres of low drip loss were more neatly and compact, and muscle cells were closer and almost less gap. However, some sarcomeres of high drip loss group were distorted, deformed and confused, and the Z line were deviated or fractured. The high drip loss group had shorter sarcomere length and larger muscle fiber gap compared with low drip loss group, and myofibrilar protein of high drip loss group was obviously degraded. Theoverall results of this study demonstrated that decrease of p H value would induce protein degradation, which resulted in different interactions of proteins and water, change of muscle fiber microstructure, muscle contraction and then high drip loss were formed.