As a result, several biomarkers were identified and were evaluated as indicative of honey's botanical origin, such as Isophorone, which can be characterized as a potential marker of arbutus honey. ## References  
* [1] da Costa, A.C.V. ; Sousa, J.M.B. ; Bezerra, T.K.A. ; da Silva, F.L.H. ; Pastore, G.M. ; da Silva, M.A.A.P. ; Madruga, M.S. Volatile profile of monofloral honeys produced in Brazilian semiarid region by stingless bees and key volatile compounds. _Food Sci. Technol._**2018**, 94, 198-207. * [2]_17.16. Determination of Vitamin \(D_{2}\) in UV-B Treated Mushrooms_**D. Z. Lantzouraki 1,2,*, G. Sotiroudis 1, T. Tsiaka 1,2, G. Koutrosios 3, N. Kalogeropoulos 4, G. I. Zervakis 3 and P. Zoumpoulakis 1,2**
* [3] Institute of Chemical Biology, National Hellenic Research Foundation 48, Vas. Constantin Ave., 11635 Athens, Greece
* [4] Department of Food Science and Technology, University of West Attica, Ag. Spyridonos, 12243 Egaleo, Greece
* [5] Laboratory of General and Agricultural Microbiology, Department of Crop Science, Agricultural University of Athens, 11855 Athens, Greece
* [6] Department of Nutrition and Dietetics, School of Health Science and Education, Harokopio University, 70 El. Venizelou Str., 17661 Athens, Greece
* [7] Correspondence: dlantzouraki@eie.grHypovitaminosis D is nowadays one of the most common nutritional disorders worldwide, associated in certain populations with a number of health risks such as hyperparathyroidismism, rickets, and osteomalacia. Among the few natural sources containing sufficient levels of vitamin D, commonly consumed mushroom species can provide substantial amounts of ergocalciferol (vitamin D2) after natural or artificial UV-light treatment, and thus they are recognised as the primary non-animal dietary source of vitamin D [1]. Within this framework, the present study aims to investigate the UV treatment as a means to rapidly increase vitamin D content in king oyster mushrooms (_Pleurotus ergysii_) in comparison to non-treated cultivated mushrooms. UV-B irradiation was used for the post-harvest irradiation of sliced samples under the controlled environment of a thermostabilized chamber. For the efficient recovery of vitamin D from the UV-B exposed mushrooms, an analytical protocol was developed, including a hot alkaline hydrolysis work-up with short extraction time and clean-up steps. Moreover, a selective and sensitive targeted Liquid Chromatography-Tandem Mass Spectrometric methodology was developed for the quantitative determination of the vitamin D forms (D2 and D3) in the studied samples. The LC-MS analysis revealed high ergocalciferol concentrations in the UV-treated mushrooms ranging from 50- to 120-fold higher vitamin D2 compared to the control group. This work was supported by the European Union and Greek national founds (European Social Fund-ESF) through the Operation Program Competitiveness, Entrepreneurship, and Innovation, under the call RESEARCH-CREATE-INNOVATE (project code: T1 EDK-02560). ## References  
* 1. Cardwell, G.; Borman, J.; James, A.; Black, L. A review of mushrooms as a potential source of dietary vitamin D. _Nutrients_**2018**, _10_, 1498. * 2. 1. 1.0% (RDA Lactation 31-50 years of age for honeys from Poland and Greece) to 1.5% (RDA Males 31-50 years of age for honeys from Poland and Greece) for Cu, and from 0.09% (RDA Males 31-50 years of age for honeys from Poland) to 0.31% (RDA Lactation 31-50 years of age for honeys from Greece) for Mg. Beyond nutritive elements, Pb, as an example of a toxic element, has been also studied. The FAO/WHO Joint Expert Committee on Food Additives (JECFA) has established a Provisional Tolerable Weekly Intake (PTWI) for several toxic elements and especially heavy metals. Results for the typical 75 kg adult show 0.03% Pb intake from honeys of both countries. ## References  
* [1] Zhang, P.; Georgiou, C.A. ; Brusic, V. Elemental metabolomics. _Brief. Bioinform._**2018**, _19_, 524-536. * [2] Regulation (EU) No. 1169/2011. REGULATION (EU) No.