Determination of (2E)-10-hydroxydec-2-enoic acid in Croatian royal jelly by high-performance liquid chromatography

Although health-promoting properties of royal jelly are known for many years, the absence of quality standards and methods prescribed for their determination leads to royal jelly adulteration. Royal jelly is a source of unique unsaturated fatty acid, (2E)-10-hydroxydec-2-enoic acid (10-HDA), and its content is considered as one of the freshness and authenticity parameter. In this study, high performance liquid chromatographic method (HPLC) with UV detection was validated and 10-HDA content in fresh royal jelly samples produced in Eastern Croatia was determined. The data about Croatian royal jelly are not available, therefore the results presented in this study could be considered as pioneer results for Croatian royal jelly characterization in respect of the 10-HDA. Method performance characteristics showed that the used method is fit for purpose. The content of 10-HDA in analysed samples varied from 1.56% up to 3.78%. According to the international recommendations for royal jelly quality, samples were fresh and authentic regarding 10-HDA content. Furthermore, the effect of packaging material on 10-HDA content was observed. Based on the obtained results, the conclusion was reached that if the samples were collected at the same time and frozen after collection, collection and storage of fresh royal jelly in glass and plastic containers had no effect on 10-HDA content