Influence Of Frozen Storage And Freeze-thawing Cycles On The Quality Of Wenchang Chicken

Frozen is one of the most important storage methods. In process of sales, transportation and processing, cold chain system is imperfect and the frozen meat experienced repeated freezing and thawing. Unfortunately, Wenchang chicken is liable to suffer spoilage due to the high content of proteins and moisture, floppy muscle tissue, reducing the acceptance of the flesh for human cosumption. Recently, considerable research efforts have mainly focused on the biochemical characteristics of muscle proteins of fish and shrimp, there is little information about the quality changes of Wenchang chicken during frozen storage, which is the high quality breeds in Hainan. Accordingly, two contents were conducted:the effects of frozen storage conditions on quality of Wenchang chicken breast and repeated freezing and thawing on quality of chicken breast and thigh. To investigate the change rules of color, texture, water retention, fat oxidation, salt soluble of myofibrillar proteins, Ca2+-ATPase activities, sulphydryl group contents and collagen content during frozen storage and freeze-thaw cycles.During-18℃,-30℃and-78℃storage, a*(redness) and b*(yellowness) of the chicken breast showed an increasing trend, while L*(lightness) was observed to decrease. The10th day, textural properties such as hardness, springiness and cohesiveness significantly reduced, then slowly descended. Salt soluble of myofibrillar proteins, sulphydryl group contents and collagen content sharply dropped in the early10th test period. And Ca2+-ATPase activities fell with prolonged storage time. Moreover, it tended to be more effective to keep the quality of chicken along with the lower frozen storage temperature and shorter frozen storage time.As the number of freeze-thaw cycles increased, a*increased first and then decreased, b*and L*is on the rise with the freezing and thawing. Hardness, springiness and cohesiveness sharply dropped after1cycle, and then decreased slowly. Water retention of muscle became worse as the thawing and cooking loss both improved. TBAR rose up with increasing number of freeze-thaw cycles. Three freeze-thaw cycles resulted in a sharp decrease in myofibrillar protein salt solubility, Ca2+-ATPase activity, sulphydryl group contents and collagen content. Comparing the chicken thigh, freeze-thaw cycles affected the quality of chicken breast more easily, and the difference were significant.Overall, lipid oxidation and protein denaturation reduced by frozen storage and freeze-thaw cycles, making the color of the muscle darken and the holding water capacity and texture worse, leading to a decline in the quality of Wenchang chicken. Therefore, controlling frozen storage conditions and improving cold chain technology is of great significance for conservation the quality of Wenchang chicken.