牛肉低温储藏过程中水分迁移与蛋白质氧化的相关性研究

Correlation Research between Water Migration and Protein Oxidation of Beef under Cryopreservation

蛋白质氧化会影响肉品的加工特性、营养价值及风味滋味,对肉制品品质影响极大。本研究以黄牛外脊为研究对象,采用低场核磁共振技术研究牛肉在4℃冷藏、-2℃冰温储藏期间水分迁移规律及其与蛋白质氧化的相关性。结果表明,随着储藏时间延长,牛肉pH、储藏损失率上升,且随着蛋白质氧化,羰基含量上升而巯基含量下降。两组牛肉结合水T_(21)和不易流动水T_(22)含量下降,自由水T_(23)含量上升,牛肉的保水性降低。相关性分析表明,在4℃冷藏条件下,T2b与巯基含量呈显著正相关(P<0.05),T_(21)与羰基含量呈显著负相关(P<0.05),T_(22)与羰基含量呈极显著负相关(P<0.01),T_(22)与巯基含量呈显著正相关(P<0.05),T_(23)与羰基含量呈极显著正相关(P<0.01)。在-2℃冰温条件下,T_(22)与羰基含量呈极显著负相关(P<0.01),T_(22)与巯基含量呈显著正相关(P<0.05),T_(23)与羰基含量呈显著正相关(P<0.05),T_(23)与巯基含量呈显著负相关(P<0.05),即水分迁移与蛋白质氧化有良好的相关性,可以通过低场核磁共振弛豫时间T2表征蛋白质的氧化,且用T_(22)来表征蛋白质氧化效果最好。

Protein oxidation would severely affect the quality of meat products via influencing their processing characteristics,nutritional values and flavors.In this study,the outer ridge of cattle was used as the research object and the low field NMR technology was employed to study the correlation of water transfer rule and protein oxidation during cold storage at 4℃and ice-temperature storage at-2℃.Results showed that the pH and storage loss rate of beef were increased with the extension of storage time,while the sulfhydryl content was decreased with the increases of protein oxidation level and carbonyl content.The content of bound water(T21)and hard-flowing water(T_(22))were decreased in the two groups,while the content of free water(T23)was increased,and the water retention was decreased.The correlation analysis showed that at 4℃,T2 bwas significantly positive-correlated with the content of sulfhydryl group(P<0.05),T_(21) was remarkably negative-correlated with the content of carbonyl group(P<0.05),T_(22) was extremely significantly negative-correlated with the content of carbonyl group(P<0.01),T_(22) was notably positive-correlated with the content of sulfhydryl group(P<0.05),T_(23) was highly significantly positive-correlated with the content of carbonyl group(P<0.01).At-2℃,T_(22) showed a significantly negative correlation with carbonyl content(P<0.01),a remarkably positive correlation with sulfhydryl content(P<0.05),T23 showed a signifi cantly positive correlation with carbonyl content(P<0.05),and a notably negative correlation with sulfhydryl content(P<0.05),which suggested that there was a good correlation between water migration and protein oxidation,and the protein oxidation could be reflected by relaxation time T2 in low field NMR,and T_(22) is the best indicator.