基于GC-MS的低盐虾酱低温发酵过程中代谢组学分析

为了阐明低盐虾酱在低温发酵过程中的代谢物特点，采用气相色谱-质谱联用技术对低盐虾酱在低温发酵过程中的代谢物进行监测；结合t检验和变量投影重要性（variable importance in projection，VIP）分析等多元统计分析，筛选出差异代谢物。结果表明，正交偏最小二乘判别分析模型显示，不同温度下发酵低盐虾酱之间的代谢物能够明显分离。2 组低盐虾酱中共有44 种主要代谢物，包括氨基酸类16 种、脂肪酸类6 种、胺类2 种、有机酸类8 种、醇类3 种、核苷酸类3 种、其他类化合物6 种。以P＜0.05和VIP＞1为筛选条件，得到30 种差异代谢物，主要包括氨基酸类7 种、酯类2 种、嘌呤类2 种、有机酸类8 种、醇类2 种和其他代谢物9 种；其中，与对照组（20 ℃）相比，低温组（10 ℃）中L-丝氨酸、L-苏氨酸、黄嘌呤、次黄嘌呤和L-谷氨酰胺显著增加，乙酸橙花酯、樱黄素和褪黑素显著减少（P＜0.01）。研究结果为进一步改善低盐虾酱生产工艺提供一定的理论依据。

Metabolomic Analysis of Low-salt Shrimp Paste during Fermentation at Low Temperature Based on Gas Chromatography-Mass Spectrometry

The metabolite profile of low-salt shrimp paste during low-temperature fermentation was investigated by metabolomics based on gas chromatography-mass spectrometry (GC-MS), and the differential metabolites were selected by multivariate statistical analysis combined with t-test and variable importance in projection (VIP) analysis. The results showed that the orthogonal partial least squares discriminant analysis (OPLS-DA) model clearly discriminated the metabolite profiles of shrimp paste samples fermented at 10 (low temperature) and 20 (control) ℃. A total of 44 metabolites were identified in the two samples, including 16 amino acids, 6 fatty acids, 2 amines, 8 organic acids, 3 alcohols, 3 nucleotides and 6 other compounds. By considering P < 0.05 and VIP > 1, 30 differential metabolites were obtained, including 7 amino acids, 2 esters, 2 purines, 8 organic acids, 2 alcohols and 9 other metabolites. The levels of L-serine, L-threonine, xanthine, hypoxanthine and L-glutamine in the low-temperature group were significantly higher than those in the control group, while the levels of nerazine acetate, zeaxanthin and melatonin were significantly lower (P < 0.01). These results provide a theoretical basis for further improving the production process of low-salt shrimp paste.