Abstract:

Objective: The aims of this study were to investigate mathematical relationships of pork tenderness with muscle fibre diameter, density and intramuscular fatty area (IFA). Method: Six varieties of cross-bred pigs (N=36) were taken as study objects, and meat or muscle samples were all from M. longissimus dorsi (ld, n=36×2 or ×3) and M. psoas major (pm, n=36 × 2 or × 3), respectively. Two-dimensional microscopy images of histomorphology characteristics of skeletal muscle were reconstruted, and mathematical relationships of pork tenderness with histomorphology characteristics were fitted. Results: The muscle fibre diameter and density in pm are thinner and denser than those in ld. However, the IFA in pm is less than that in ld. The muscle fibre diameter is the most significant factor affecting the pork tenderness with the linear coefficient (r) of 0.966 (p <0.01). It means that the thicker the muscle fibre is, the worse the pork tenderness is. Otherwise, the muscle fibre density varies with its diameter. The muscle fibre density decreases, when its diameter increases. So the linear relationship between the muscle fibre density and pork tenderness is significantly negative (r=0.905, p<0.05). The tenderer the muscle fibre is, the denser the muscle fibre is. But, the effect of muscle fibre density on pork tenderness is less than muscle fibre diameter. In this study, IFA is only about 3% of total muscle area, so it is not enough to carry weight on pork tenderness. Conclusion: Muscle fibre diameter and density have remarkable effect on muscle tenderness, whereas IFA mostly affects the smack but not tenderness. In five vatieties of Shennong, their muscle fibre is thinner with the better pork quality (tenderness) because these pigs are bred from Taihu swine.

Key words: tenderness, mscle fibre density, intramuscular fatty area, pork