Abstract: A high-performance liquid chromatography method was developed to determine the contents of 5-hydroxymethylfurfural and furfural in liquid milk. The samples were extracted with oxalic acid solution in a boiling water bath, then the protein and fat were precipitated by adding trichloroacetic acid solution. The supernatant was separated on an XDB-C18 column (4.6 mm × 250 mm, 5 μm) using 10% acetonitrile solution as the mobile phase. The analytes were detection with an ultraviolet detector and quantified by the external standard method. The experimental results showed that the correlation coefficient of 5-hydroxymethylfurfural was 0.999 8, with a spiked recovery ranging from 84.6% to 94.3%, a limit of detection (LOD) of 0.005 mg/kg, and a coefficient of variation (CV) of 0.15% to 0.36%. For furfural, the correlation coefficient was 0.999 4, with a spiked recovery rate ranging from 73.7% to 92.0%, a LOD of 0.005 mg/kg, and a CV of 0.95% to 1.54%. This method is characterized by simple operation, low cost, and excellent separation performance, and it is suitable for the quantitative analysis of 5-hydroxymethylfurfural and furfural in liquid milk, providing technical support for the quality control and process optimization of dairy products.

Key words: furfural; 5-hydroxymethylfurfural; high-performance liquid chromatography; liquid milk

摘要： 采用共培养和琼脂扩散法评价长双歧杆菌长亚种BD3150及其无细胞发酵上清液对肠出血性大肠杆菌 O157:H7(enterohemorrhagic Escherichia coli O157:H7,EHEC O157)生长的抑制作用?结果表明,以2’-岩藻糖基乳糖作为唯一碳源,共培养6?18 h后EHEC O157相对丰度较以葡萄糖为碳源下降至72.3%和67.8%?进一步研究菌株长双歧杆菌长亚种BD3150在改良MRS培养基中所得发酵上清液的抑菌特性,确定其最佳制备条件为接种量3.0%?发酵温度37 ℃?发酵时间36 h,同时发现抑菌圈直径与上清液pH值呈负相关?通过调节无细胞发酵上清液的pH值和超滤离心(3 kDa?7 500×g?25 min),发现无细胞发酵上清液中主要抑菌物质为有机酸?

关键词: 双歧杆菌; 抑菌活性; 琼脂扩散法; 无细胞上清液; 母乳寡糖