Determination of free N-acetylneuraminic acid in edible bird nest: A development of chemical marker for quality control

Abstract Edible bird nest (EBN) is a common health food consumed in Asia. The exaggerated skincare functions resulted in the abnormally high market value. Fake EBN started to appear in the market for the sake of its profits. A reliable authenticate method is in urgent need. Here, the determination of a free form of sialic acid, N-acetylneuraminic acid (NANA), was developed to distinguish EBN according to their grading. High amount of free NANA was revealed in red and yellow EBN: both white and grass EBN contained free NANA at low level. Unlike total NANA content measurement, fake EBN did not show detectable amount of free NANA. Moreover, the water extract of EBN showed anti-tyrosinase activity, and which was in line to amount of free NANA. Thus, the amount of free NANA could differentiate fake EBN from the genuine one, as well as its grading. In conclusion, the quantitation of free NANA by triplequadrupoles liquid chromatography tandem mass spectrometry (LC-MS/MS QQQ) was shown to be the best method in EBN authentication. In addition, the amount of free NANA in EBN was in accord to anti-tyrosinase activity of EBN.