Abstract: In an effort to explore the oxidation pattern of sarcoplasmic proteins in yak meat under chilled conditions, Longissimus dorsi muscles of male and female yaks from different populations were packaged in air or vacuum and stored under chilled conditions, and the oxidation of sarcoplasmic proteins in yak meat was evaluated by measurement of carbonyl content, sulfhydryl content and hydrophobicity, UV absorption spectroscopy and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that the carbonyl content of sarcoplasmic proteins in both packaging treatments followed an increasing-decreasing-increasing trend (P < 0.05), whereas the total sulfhydryl content decreased with the prolongation of storage time. Surface hydrophobicity of air-packaged yak meat increased (P < 0.05), while that of vacuum-packaged meat revealed an initially increase and then decreased. Significant differences were observed for carbonyl content, total sulfhydryl content and surface hydrophobicity between different yak populations under the same packaging conditions (P < 0.05), but not between the genders (P > 0.05). For both packaging trearments, the most apparent change in the second-order derivative UV absorption spectra of sarcoplasmic proteins occurred on the 3rd day of the storage. As oxidation proceeded, the molecular masss of sarcoplasmic proteins decreased, and the intensity of all protein bands declined. During storage, the degradation degree of sarcoplasmic proteins under air packaging was larger than under vacuum packaging. UV absorption spectra and SDS-PAGE patterns of sarcoplasmic proteins in both packaging treatments did not vary between populations or genders after the same storage time. From this study we concluded that sarcoplasmic protein oxidation in yak meat during cold storage was closely related to packaging methods and populations but not genders.

Key words: yak meat, cold storage, sarcoplasmic protein, oxidation