这项探索性研究的目的是评估具有不同最终pH值(pHu)和衰老时期的牛腰背肌的脂质组和代谢组特征的变化。牛的肌肉被归类为正常,中间,或从巴西商业屠宰场收集的高PHU,切成牛排,单独真空包装,并在2℃下老化3天(3-d)或21天(21-d)。分析了肌肉提取物的两种脂质的概况,通过质谱(通过直接流动注射),和代谢物,通过核磁共振,下游多元数据分析。作为主要结果,成对比较确定C12:0和C14:0酰基肉碱作为中间pHu肌肉的潜在生物标志物,它们与脂质分解代谢有关,用于替代能量代谢,并表明死后蛋白质断裂较少。有趣的是,死后早期(3d)的精氨酸浓度可能会影响先前报道的正常和高pHu肌肉的压痛改善。此外,富马酸盐的上调,甲酸盐,和乙酸盐在21天老化时增加的pHu肌肉表明更强烈的三羧酸循环,氨基酸降解,和丙酮酸被活性氧氧化,分别。这三种化合物(富马酸盐,甲酸盐,和醋酸盐)在21天老化时对高pHu的肌肉进行了统计学区分。正常的pHu肌肉显示较高浓度的糖原分解和糖酵解代谢产物,包括葡萄糖,甘露糖,还有丙酮酸盐.因此,我们的结果提高了对不同年龄至21天的pHu组牛肉死后生化变化的认识,这对于了解支撑公牛肉品质变化的机制至关重要。
The objective of this exploratory study was to assess the changes on lipidome and metabolome profiling of Longissimus lumborum bull muscle with different ultimate pH (pHu) and aging periods. The bull muscles classified as normal, intermediate, or high pHu were collected from a Brazilian commercial slaughterhouse, cut into steaks, individually vacuum-packaged, and aged for 3 days (3-d) or 21 days (21-d) at 2 °C. Muscle extracts were analyzed for the profiles of both lipids, by mass spectrometry (via direct flow-injection), and metabolites, by nuclear magnetic resonance, with downstream multivariate data analysis. As major results, pairwise comparisons identified C12:0 and C14:0 acylcarnitines as potential biomarkers of the intermediate pHu-muscle, which are related to lipid catabolism for alternative energy metabolism and indicate less protein breakage postmortem. Interestingly, the concentration of arginine at early postmortem aging (3-d) may influence the previously reported improved tenderness in normal and high pHu-muscles. Moreover, upregulation of fumarate, formate, and acetate with increased pHu muscle at 21-d aging indicate more intense tricarboxylic acid cycle, amino acid degradation, and pyruvate oxidation by reactive oxygen species, respectively. These three compounds (fumarate, formate, and acetate) discriminated statistically the muscle with high pHu at 21-d aging. The normal pHu-muscle showed higher concentrations of glycogenolysis and glycolysis metabolites, including glucose, mannose, and pyruvate. Hence, our results enhance knowledge of postmortem biochemical changes of beef within different pHu groups aged up to 21 days, which is essential to understand the mechanisms underpinning bull meat quality changes.