Biochemical and physicochemical changes in spaghetti meat during refrigerated storage of chicken breast

Authors: TASONIERO, GIULIA - Oak Ridge Institute For Science And Education (ORISE); Zhuang, Hong; Bowker, Brian

Submitted to: Frontiers in Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2022
Publication Date: 6/15/2022
Citation: Tasoniero, G., Zhuang, H., Bowker, B.C. 2022. Biochemical and physicochemical changes in spaghetti meat during refrigerated storage of chicken breast. Frontiers in Physiology. https://doi.org/10.3389/fphys.2022.894544.
DOI: https://doi.org/10.3389/fphys.2022.894544

Interpretive Summary: In fast-growing modern broilers there is an increasing incidence of a breast meat quality defect known as Spaghetti Meat (SM). Relatively little is known about how SM influences postmortem changes in the muscle tissue and meat quality. This study investigated the progression of postmortem protein degradation in SM and its impact on muscle water properties. The SM condition was observed to cause significant alterations to the water properties of the breast meat but had minimal impact on the degree of muscle protein degradation at 0, 3, and 7 days postmortem. These data suggest that mechanisms other than changes in the proteolytic system of the muscle account for the altered phenotype and meat quality characteristics of breast muscles with the SM condition.

Technical Abstract: The aim of the study was to provide insight on the postmortem evolution of Spaghetti Meat (SM) and its impact on myowater properties. During two trials, 30 severe SM and 30 unaffected (N) fillets were subjected to 7 days of refrigerated storage. At days 0, 3 and 7, NMR traits, myofibrillar proteins profiles, calpain activity, free calcium concentration as well as desmin and troponin-T (TnT) pattern degradation were assessed on 5 different breasts per group. A two-way ANOVA was carried out considering group (G: N and SM), time (T: 0, 3, 7) and their interaction G × T as fixed effects and trial as a random effect. In SM fillets, the intramyofibrillar water population exhibited longer relaxation times (T21; N = 45.9 vs SM = 46.9 ms; P = 0.0172) and a lower proportion compared to N (P21; N = 83.8 vs SM = 80.7%; P = 0.0118). Concurrently, SM was characterized by a greater proportion of extramyofibrillar water (P21; N = 15.5 vs SM = 18.8%; P = 0.0080) possessing a longer relaxation time (T22; N = 180 vs SM = 200 ms; P = 0.0001). Overall, the SM myopathy had only a minor impact on the myofibrillar proteins profiles and did not exert significant effects on either free calcium concentration, calpain activity and protein degradation. Differently, postmortem storage time exerted a strong effect on the measured traits. Indeed, a redistribution of myowater occurred over time in both N and SM fillets, and these changes in NMR traits reflected the proteolytic processes taking place during meat aging. As the concentration of free calcium increased from day 0 to 7 (P = 0.0392), casein zymograms indicated a progressive decrease in native µ/m calpain activity concomitant with the accumulation of its autolyzed form (P = 0.0031). The electrophoretic profiles of myofibrillar proteins from both N and SM fillets exhibited a similar progression of protein degradation with postmortem storage time. As a result of storage, the abundance of the intact desmin decreased (d0 = 52.7%; d3 = 41.6%; d7 = 34.4%), coupled with the accumulation of its 39-kDa degradation product (d0 = 47.3%; d3 = 58.4%; d7 = 65.7%; P = 0.0001). Overall, the lack of significant interaction effects between muscle condition and storage period suggested that SM and N breast meat experience similar proteolytic and physical changes during the postmortem period.