Characterization of loquat (Eriobotrya japonica Lindl.) honey botanical origin according to its chitinase activity

Bees make honey from the nectar that they collect from flowers. The characteristics of honey are closely associated to original botanical species. Compare with sugars in honey, proteins are minor components but usually used as an important honey quality evaluation parameters. Flower-origin proteins could be a good marker for the authentication. However, as a minute component in honey proteome, plant origin proteins are hard to be detected in honey by regular proteomic approaches, such as gel-based techniques. In this study, Eriobotrya japonica Lindl. (loquat) nectar and its derivative monofloral honey were systematically compared, especially regarding the proteomes and enzymatic activities. Using two-dimensional electrophoresis and mass spectrometry, only bee-originated proteins were detected in loquat honey which were major royal jelly proteins and two uncharacterized proteins. Xylosidase, thaumatin, and two kinds of chitinases were detected in loquat floral nectar by the gel-based proteomic approach. To our knowledge, it is the first study to analysis nectar-originated enzymes’ activity in honey and we proposed that the zymography of chitinase is a potential marker for honey botanical origin authentication.