Identification of Adulterated Honey by UPLC-Q-Exactive Quadrupole-Electrostatic Field Track Trap High Resolution Mass Spectrometry

In order to provide a new idea and method for identification of adulterated honey,the composition and structure of peptides in four kinds of unauthorized honey and two kinds of adulterated honey were identified by ultra-high performance liquid chromatography-quadrupole-electrostatic field orbital trap high resolution mass spectrometry,and the differences between unauthorized honey and adulterated honey peptides were discussed. Honey protein was precipitated with 20% trichloroacetic acid. The obtained honey protein was enzymatically hydrolyzed by trypsin and then purified by C₁₈ solid phase extraction column. Then the digested sample by trypsin was separated by gradient elution with 0.1% formic acid and acetonitrile as mobile phase and determined by high resolution mass spectrometry(Q-Exactive)in Full MS/ddMS² mode. MaxQuant software was used to analyze the results of mass spectrometry. The analyzed peptides was comparised on Uniprot by Blast. The results showed that Major Royal Jelly Protein(MRJPs)existed in all four kinds of unauthorized honey,and were not detected in two kinds of adulterated honey,and more than 80% of the peptides identified in four kinds of unadulterated honey come from honeybees(Apis cerana cerana,Apis cerana,Apis mellifera). By comparing the enzymatic hydrolysis sequence of six kinds of honey,it was found that EYILVLSNK was detected in four kinds of unadulterated honey and not in two kinds of adulterated honey. Therefore,EYILVLSNK,a peptide digested by MRJP1 of Apis mellifera,might be a potential peptidest for distinguishing true and false honey.