The influence of fertilization on chemical composition of 'Grk bijeli'

Grk bijeli je sorta vinove loze usko vezana za mjesto Lumbarda na otoku Korčuli. Ime je dobila po gorkastom okusu, odnosno po riječi 'gark' koja na staroslavenskom ima značenje 'gorak'. Grk je jedna od rijetkih sorata koja posjeduje funkcionalno ženski tip cvijeta. Zbog nepravilnosti u građi cvijeta te često sterilnog polena dolazi do lošije oplodnje. U grozdu se formiraju velike, sjemene bobice te male, besjemene bobice - ‘pasoline’. Uslijed lošije oplodnje dolazi do većeg udjela pasolina u grozdu te na posljetku nižeg priroda. Pretpostavlja se kako ove dvije vrste bobica imaju različita kemijska svojstva te se samim time izravno povezuje razina oplodnje i kvaliteta vina Grk. U ovom istraživanju utvrđen je kemijski sastav sjemenih bobica i pasolina. Od polifenolnih spojeva pasoline su sadržale značajno više koncentracije gotovo svih flavonoidnih spojeva, kumarne kiseline, ferulične kiseline te resveratrola. S druge strane sjemene bobice bile su bogatije kaftarnom, fertatričnom te kavnom kiselinom. Pasoline su također bile bogatije aromatskim spojevima E-2-heksanal te linalol, no značajnih razlika u ukupnoj koncentraciji aromatskih spojeva nije bilo. U osnovnim pokazateljima kakvoće značajnih razlika, također, nije bilo.Grk bijeli is grapevine variety important for viticulture of Lumbarda area on the island of Korčula. Variety name is associated with slavonic synonym 'gark' or 'bitter', after the slightly bitter aftertaste of the Grk wine. Grk is one of the rare grape varieties with functionally female flower. Becouse of the structural irregularities and sterile pollen, fertilization is often poor. Two types of berries are developed in the cluster, large, seeded berries and small, seedless berries – 'pasoline'. Due to the poor fertilization, a great share of cluster are seedless berries, which consequently leads to lower yield. It is believed that these two types of berries have different chemical properties which directly connects fertilization rate with the Grk wine quality. This research determined the chemical content of seeded and seedless berries. Seedless berries had higher concentrations of almost all flavonoid compounds, coumaric acid, ferulic acid and resveratrol. On the other hand, seeded berries had higher content of caftaric, fertaric and caffeic acid. Seedless berries ‘pasoline’ were also richer in aromatic compounds: E-2-hexanal and linalol, although significant difference was not determined in total aromatic compounds. Also, there were not significant differences in basic quality indicators