Limit Test and pH Determination of 5-Hydroxymethylfurfural in Jiulongteng Honey

[Objectives]To explore the effect of storage time on pH and 5-hydroxymethylfurfural content in Jiulongteng honey.[Methods]The pH of Jiulongteng honey was determined by neutralization titration with sodium hydroxide standard solution.The content of 5-hydroxymethylfurfural in Jiulongteng honey was determined by HPLC.Chromatographic conditions:ZORBAX SB-C 18 column(250 mm×4.6 mm,5μm)from Agilent Co.,Ltd.,acetonitrile-0.1%formic acid solution(5:95)as mobile phase,flow rate of 0.8 mL/min,5-hydroxymethylfurfural detection wavelength of 284 nm,guanosine detection wavelength of 254 nm.[Results]The pH of 12 batches of Jiulongteng honey was 3.70-3.84 in the new honey stage,3.92-4.05 in the old honey stage 1,and 4.25-4.53 in the old honey stage 2;5-hydroxymethylfurfural was not detected in the new honey stage,5-hydroxymethylfurfural was detected in FM-001 in the old honey stage 1,and 5-hydroxymethylfurfural was detected in most samples in the old honey stage 2.[Conclusions]The pH and 5-hydroxymethylfurfural content of 12 batches of Jiulongteng honey met the requirements within 3 years of storage.There was no 5-hydroxymethylfurfural in Jiulongteng honey,but with the extension of storage time,the detection amount of 5-hydroxymethylfurfural increased significantly even if Jiulongteng honey was stored at low temperature.Therefore,5-hydroxymethylfurfural can be used as an important indicator of honey freshness.