基于GC-MS代谢组学分析大鲵肉冷藏过程中肌肉代谢产物差异

为建立大鲵肉冷藏过程中肌肉理化指标与其代谢产物的关联，采用气相色谱-质谱联用非靶向代谢组学结合多元统计模型探究大鲵肉在4 ℃不同冷藏时间（0、2、4、8 d）肌肉代谢物的差异。结果表明，大鲵肉样品冷藏8 d与冷藏0、2、4 d相比差异较大。以偏最小二乘判别分析和变量投影重要性（variable importance in projection，VIP）值为标准进行筛选（VIP≥1，t检验P＜0.05），不同冷藏时间大鲵肉中共筛选出69 种差异代谢物，包括有机酸类及其衍生物（21 种）、氨基酸类及其衍生物（14 种）、糖类及其衍生物（7 种）、核苷酸类及其衍生物（10 种）、胺类及其衍生物（6 种）和其他类化合物（11 种）。层次聚类热图可将不同冷藏期大鲵肉样品分为3 类：冷藏前期（0～2 d），冷藏中期（4 d）和冷藏后期（8 d）。京都基因与基因组百科全书富集分析表明，在大鲵肉冷藏期间较为重要的代谢通路为嘌呤代谢、氨酰-tRNA生物合成、乙醛酸和二羧酸代谢、丙酮酸代谢、三羧酸循环。代谢通路映射及Pearson相关性分析表明，L-赖氨酸、L-丝氨酸、L-异亮氨酸、L-蛋氨酸、丙酮酸、丁二酸和甘氨酸可作为大鲵肉品质变化的潜在标记物。

Gas Chromatography-Mass Spectrometry-Based Metabolomic Analysis of Differential Muscle Metabolites in Giant Salamander (Andrias davidianus) Meat during Cold Storage

In order to establish the correlation between physicochemical indexes and muscle metabolites in giant salamander meat during cold storage, differential metabolites between giant salamander muscle stored for different periods (0, 2, 4 and 8 days) at 4 ℃ were analyzed by gas chromatography-mass spectrometry (GC-MS) non-targeted metabolomics combined with multivariate statistical model. The results showed that the composition of metabolites in giant salamander muscle refrigerated for 8 days was significantly different from those stored for 0, 2 and 4 days. According to partial least squares-discriminant analysis (PLS-DA) and variable importance in projection (VIP) (VIP ≥ 1, P < 0.05 in t-test), 69 differential metabolites were identified including organic acids and their derivatives (21), amino acids and their derivatives (14), sugars and their derivatives (7), nucleotides and their derivatives (10), amines and their derivatives (6), and other compounds (11). According to the hierarchical cluster heatmap, the giant salamander meat samples could be divided into three groups: early (days 0–2), middle (day 4) and late stages (day 8). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the important metabolic pathways during the cold storage of giant salamander meat were purine metabolism, aminoacyl-tRNA biosynthesis, glyoxylic acid and dicarboxylic acid metabolism, pyruvate metabolism and the tricarboxylic acid cycle. Metabolic pathway mapping and Pearson’s correlation analysis showed that L-lysine, L-serine, L-isoleucine, L-methionine, pyruvic acid, succinic acid, glycine could be used as potential markers for the change in meat quality of giant salamander.