Study On Eating Quality Characteristics Of Xinjiang Lamb And Related Influential Factors

Tenderness is an important palatability of lamb and intrinsic-extrinsic factors influence on meat tenderness. This research is combined with the actual production of Xinjiang mutton, the chemical components, connective tissue residue, collagen content and its solubility, pH, myofybrillar fragmentation index (MFI), shear force, water holding capacity and meat colour were determined to study the effect of breed, anatomical location, postmortem ageing and frozen storage on lamb tenderness. And objectively evaluated the mechanism of changes in lamb tenderness and related characteristics. The details are as follows:1. Eating quality characteristics of muscle from different sheep breedsThe M longissimus dorsi were removed from each carcass of the three breeds such as Bashbay sheep, Altay sheep and Xinjiang Merino to determine the tenderness and related characteristics. The results indicated that, there were significant (P<0.05) or extremely significant (P<0.01) differences in moisture, crude fat, pH, MFI, water loss and water holding capacity among breeds, but were not differences in connective tissue residue, collagen content and its solubility, shear force and colour (P>0.05). Compare to other breeds, Altay sheep had a best tenderness. The moisture, insoluble collagen content, pH, MFI, water loss and water holding capacity closely related to shear force (P<0.01).2. Eating quality characteristics of Iamb from different anatomical locationsThe M supraspinatus, M glutens, and M longissimus dorsi were removed from Bashbay sheep to determine the tenderness and related characteristics. The results indicated that, the crude protein (P<0.G5), collagen content (P<0.05), pH (P<0.01), shear force (P<0.01) and colour (P<0.05) were influenced by breed. Crude protein, ash content, connective tissue residue, MFI, cooking loss, water loss, water holding capacity and colour were main factors to affect the tenderness of lamb from different anatomical locations. The M longissimus dorsi had the highest protein (P<0.01), brighter colour (P<0.05), and the best tenderness (P<0.01).3. Change in tenderness quality characteristics of lamb during postmortem ageingThe M longissimus dorsi were removed from Altay sheep, and ageing at4℃for1、2、3、5、7d to determine the tenderness and related characteristics and measure the microscopic structure. The results indicated that, as the frozen storage time increase, the moisture content, collagen solubility, pH, MFI, water holding capacity increased (P<0.05), the connective tissue residue decreased (P>0.05), and the structure of perimysium and endomysium was damaged, finally the tenderness was improved (P>0.05).4. Change in tenderness quality characteristics of lamb during frozen storageThe M supraspinatus, M gluteus, and M longissimus dorsi were removed from Bashbay sheep to enable a comparative analysis between the anatomical locations, and the samples were then frozen and stored at-18℃for0.5,1,2,3,7,15and30d in order to test the effect of frozen storage time on the tenderness and related characteristics and the microscopic structure. Breed, anatomical location, time of frozen storage, and interaction between breed and time of frozen storage, influenced the moisture content and pH (P<0.01). During the frozen storage of30d, the collagen content, MFI and cooking loss of lamb increased, the crude fat content decreased, and the structure of perimysium and endomysium was significantly changed, and the shear force gradually decreased, the tenderness was improved. The tenderness of M longissimus dorsi was significantly increased during frozen storage (P<0.05).