Aminokiselinski profil medljikovaca određen metodom tekućinske kromatografije uz fluorescencijski detektor

Medljikovac proizvode pčele od slatkog soka (medne rose ili medljike) kojeg luče biljke ili različite vrste insekata koji žive na bjelogoričnom i crnogoričnom drveću. Imajući u vidu da kemijski sastav meda prvenstveno ovisi o podrijetlu medljike/nektara, u ovom diplomskom radu određen je aminokiselinski sastav medljikovaca kako bi se utvrdile eventualne specifičnosti u udjelima pojedinih aminokiselina ovisno o podrijetlu. Za potrebe dokazivanja botaničkog podrijetla provedena je melisopalinološka i senzorska analiza, a određeni su i odabrani fizikalno-kemijski parametri kvalitete. Od 13 analiziranih uzoraka, 7 medljlikovaca je podrijetlom od medljike sa crnognoričnog drveća ili ona prevladava u uzorcima, a 6 uzoraka je podrijetlom od medljke sa bjelogorice. Za određivanje aminokiselina korištena je HPLC metoda uz prethodnu derivatizaciju sa o-ftaldialdehidom (OPA) i 9-fluorenilmetil kloroformatom (FMOC-Cl). Najzastupljenije aminokiseline u medljikovcima su: prolin, fenilalanin, asparaginska kiselina, glutaminska kiselina i cistein. Najmanje zastupljene su histidin, lizin, metionin, triptofan i leucin. Uočava se veći ukupni udio aminokiselina u medljikovcima od bjelogorične medljike u odnosu na medljikovce od crnogorične medljike. Po ukupnim aminokiselinama izdvaja se medljikovac hrasta sladuna sa 734,70 mg/kg dok je ukupni udio aminokiselina u ostalim ispitivanim uzorcima iznosio 114,57 – 378,08 mg/kg. Honeydew honey is produced by the honey bees from sweet sap (honeydew) secreted by plants or different types of insects that live on latifoliae and coniferous trees. Specific types of honeydew can be produced without the participation of insects. Bearing in mind that the chemical composition of honey primarily depends on the origin of honeydew/nectar, the aim of this study was to determine the amino acid composition of honeydew in order to determine possible specificities in the proportions of individual amino acids depending on the origin of the honeydew. For the purposes of determination of the botanical origin, a melissopalynological and sensory analysis was carried out, and selected physico-chemical quality parameters were determined. Out of 13 analysed samples, 7 honeydews originate from honeydew from coniferous trees or it predominates in the samples, and 6 samples originate from honeydew from latifoliae trees. The HPLC method with prior derivatization with o-phthaldialdehyde (OPA) and 9-fluorenylmethyl chloroformate (FMOC-Cl) was used for the determination of amino acids. The most abundant amino acids in honeydew are proline, phenylalanine, aspartic acid, glutamic acid and cysteine. The least represented are histidine, lysine, methionine, tryptophan and leucine. A higher total proportion of amino acids is observed in honeydews from latifoliae honeydew compared to honeydews from coniferous honeydew. In terms of total amino acids, the Quercus frainetto honeydew honey stands out with 734.70 mg/kg, while the total amino acids content in the other tested samples was 114.57 - 378.08 mg/kg.