The chemical characterization of peach kernels (Prunus persica L.)

Istraţivanjima u okviru ove doktorske disertacije na osnovu sadrţaja pojedinih fitohemikalija izvršena je hemijska karakterizacija semena 25 sorti/genotipova breskve razliĉitog genetiĉkog i geografskog porekla gajenih pod istim klimatskim uslovima na teritoriji Srbije u okviru kolekcije oglednog dobra „Radmilovac‖ Poljoprivrednog fakulteta Univerziteta u Beogradu. U cilju utvrĊivanja sliĉnosti i razlika izmeĊu pojedinih genotipova breskve, kao i odreĊivanja potencijalnih biomarkera njihovog genetiĉkog i geografskog porekla, istraţivanja su obuhvatila analizu varijabilnosti standradnih sorti (poreklom iz SAD i Italije), perspektivnih hibrida (nastalih ukrštanjem standardnih sorti) i nekoliko genotipova vinogradarske breskve kao autohtone sorte iz Srbije. Osim podele po poreklu, ispitivani genotipovi breskve razlikovali su se i po vremenu sazrevanja ploda. Gasna hromatografija sa plameno-jonizacionim detektorom (Gas Chromatography with Flame Ionization Detector, GC-FID) korišćena je za odreĊivanje sastava masnih kiselina u uzorcima semena breskve. Bez obzira na razliĉitost izmeĊu genotipova, ulje semena breskve ima sliĉan sastav masnih kiselina koji se najvećim delom sastoji od nezasićenih masnih kiselina, oleinske i linolne kiseline. Razlika izmeĊu sorti/genotipova breskve se ogleda samo u razlici u procentualnim koncentracijama najzastupljenijih masnih kiselina. Ulje semena breskve ima nizak ukupni sadrţaj zasićenih masnih kiselina, manji od 15%, i to uglavnom sadrţi palmitinsku i stearinsku kiselinu. Fenolni profil semena breskve odreĊen je ultra-visokoefikasnom teĉnom hromatografijom spregnutom sa hibridnim masenim spektrometrom (Ultra High-Perfomance Liquid Chromatography coupled with a hybrid mass spectrometer - Linear Trap Quadrupole and OrbiTrap mass analyzer, UHPLC-LTQ OrbiTrap MS/MS). U uzorcima semena breskve detektovane su razliĉite klase fenolnih jedinjenja i nekoliko organskih kiselina sa manjim brojem C-atoma. Od fenolnih jedinjenja semena breskve u najvećoj koliĉini sadrţe katehin i šest fenolnih kiselina: protokatehuinsku, p-hidroksibenzoevu, p-hidroksifenilsirćetnu, hlorogenu, p-kumarinsku i ferulinsku kiselinu. Kvantifikacija saharida izvršena je upotrebom visoko-efikasne anjonske hromatografije sa elektrohemijskom detekcijom (High-Performance Anion Exchange Chromatography with Pulsed Amperometric Detection, HPAEC-PAD...The investigations in scope of this doctoral dissertation were based on the content of a several phytochemicals and it comprised chemical characterization of kernels of 25 peach cultivars/genotypes differing in genetic and geographical origin cultivated under the same climatic conditions in the territory of Serbia within a collection of the „Radmilovac‖ Experimental Station of the University of Belgrade - Faculty of Agriculture. In order to determine the similarities and differences between the individual cultivars/genotypes of the peach, as well as to identify potential biomarkers of their genetic and geographical origin, the research included an analysis of the variability of standard cultivars (originating in the USA and Italy), promising hybrids (created by standard cultivars cross-breeding) and several vineyard peach genotypes as autochthonous cultivars from Serbia. Except from this division, the examined genotypes of the peach differed according to the ripening time. Gas chromatography with flame ionization detector (GC-FID) was used to determine the composition of fatty acids in samples of the peach kernels. Regardless of the difference between genotypes, the peach kernel oil has the similar fatty acid composition, which the most consists of unsaturated fatty acids, oleic and linoleic acids. Variation between varieties/genotypes of peach is only seen in the difference in the percentage concentrations of the most abundant fatty acids. The kernel oil has a low total saturated fatty acid content less than 15%, which is mainly composed of palmitic and stearic acids. The phenolic profile of peach kernels was determined by ultra-high-perfomance liquid chromatography coupled with a hybrid mass spectrometer (UHPLC-LTQ OrbiTrap MS/MS). In samples of peach kernels, different classes of phenolic substances and several organic acids with small number of C atoms were detected. Among phenolic compounds, the most abundant in peach seeds were catechin and six phenolic acids: protocatechuic, p-hydroxybenzoic, p-hydroxyphenylacetic, chlorogenic, p-coumaric and ferulic acids. The quantification of saccharides was perfomed using high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD)..