Određivanje antocijanina i hidroksicinamske kiseline te njihova količina u različitim vrstama trešnje Prunus avium L. iz Nove Gorice (Slovenija)

The anthocyanins and hydroxycinnamic acids in 5 cultivars of dark coloured sweet cherries were characterised and quantified by means of HPLC and UV-VIS spectrophotometry. Phenolic components were extracted with pure methanol, without addition of acid and water. The samples were diluted in the mixture of methanol and formic acid just before the injection on the column and separated on Hypersil PEP 300 C18 chromatographic column using gradient solvent system consisting of formic acid, water and methanol. DAD detector was employed and two wavelengths were chosen for determination of different components; 320 nm for hydroxycinnamates and 520 nm for anthocyanins. We detected the presence of cyanidin-3-glucoside and cyanidin-3-rutinoside as major anthocyanins, while pelargonidin-3 rutinoside was identified among minor pigments. The major hydroxycinnamic acids were characterised as neochlorogenic acid and 3\u27-p-coumaroylquinic acid. Total anthocyanin content (expressed as cyanidin-3-glucoside) ranged from 29 to 62 mg/100 g of pitted cherry fresh weight (FW), with the highest content observed in Petrovka, a local cultivar. Concentrations of neochlorogenic acid and 3’-p coumaroylquinic acid ranged from 19.5 to 53.0 mg/100 g FW and from 7.5 to 50.6 mg/100 g FW, respectively. The relative amounts of these two phenolic acids varied widely between the cherry cultivars examined in this study.Antocijanini i hidroksicinamske kiseline određeni su i utvrđena je njihova količina HPLC- i UV-VIS-spektrofotometrijom u pet vrsta tamnocrvenih trešanja. Fenolni spojevi ekstrahirani su čistim etanolom bez dodatka kiseline i vode. Uzorci su bili razrijeđeni smjesom metanola i mravlje kiseline neposredno prije injekcije. Na kromatografskoj koloni Hypersil PEP 300 C18 razdvojeni su uzorci korištenjem gradijenta sustava otapala od mravlje kiseline, vode i metanola. Da bi se odredili pojedini sastojci, primijenjen je DAD-detektor i dvije valne duljine, i to: 320 nm za hidroksicinamate i 520 nm za antocijanine. Kao glavni sastojak antocijanina utvr|ena je prisutnost cijanidin-3-glukozida i cijanidin-3-rutinozida, dok je utvrđena manja količina pelargonidina-3-rutinozida. Glavne hidroksicinamske kiseline bile su neoklorogenska i 3´-p-kumaroil-kinska kiselina. Ukupni udjel antocijanina (izražen kao cijanidin-3-glukozid) iznosio je od 29 do 62 mg / 100 g mase svježih plodova bez koštica pri čemu je najveću vrijednost imala vrsta Petrovka. Koncentracija neoklorogenske kiseline iznosila je od 19,5 do 53,0 mg / 100 g svježih trešanja bez koštica, a 3´-p-kumaroil- kinske kiseline 7,5–50,6 mg / 100 g. Relativne količine tih dviju fenolnih kiselina znatno su se razlikovale među pojedinim ispitivanim vrstama trešanja