Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, SP 13418-900, Brazil.
Lipid Marker Omics Sciences, Pirassununga, SP 13638-407, Brazil.
Meat Sci. 2024 Nov;217:109621. doi: 10.1016/j.meatsci.2024.109621. Epub 2024 Aug 3.
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.
本探索性研究的目的是评估具有不同最终 pH 值（pHu）和成熟时间的长肌牛肌肉的脂质组和代谢组特征的变化。本研究从巴西商业屠宰场采集正常、中等和高 pHu 的牛肌肉，切成牛排，分别进行真空包装，并在 2°C 下分别成熟 3 天（3-d）或 21 天（21-d）。通过质谱法（通过直接流动注射）分析肌肉提取物的脂质谱，通过核磁共振分析代谢物谱，并进行下游多元数据分析。主要结果表明，成对比较确定 C12:0 和 C14:0 酰基辅酶 A 为中等 pHu 肌肉的潜在生物标志物，这与替代能量代谢的脂质分解有关，表明死后蛋白质分解较少。有趣的是，早期死后成熟（3-d）时精氨酸的浓度可能会影响正常和高 pHu 肌肉中报道的改善嫩度。此外，在 21-d 成熟时，高 pHu 肌肉中富马酸、甲酸盐和乙酸盐的上调表明三羧酸循环、氨基酸降解和活性氧的丙酮酸氧化更为剧烈。这三种化合物（富马酸、甲酸盐和乙酸盐）在统计学上区分了 21-d 成熟时 pHu 值高的肌肉。正常 pHu 肌肉中糖酵解和糖异生代谢物（包括葡萄糖、甘露糖和丙酮酸）的浓度较高。因此，我们的研究结果增强了对不同 pHu 组牛肉在 21 天成熟过程中死后生化变化的认识，这对于理解公牛肉品质变化的机制至关重要。
