20.500.12556/RUL-112659 Vpliv osvetljevanja s svetlobo svetlečih diod različnih valovnih dolžin na kemijsko sestavo plodov črnega ribeza (Ribes nigrum L.) Influence of light emitting diodes of different wavelength on chemical composition of black currant (Ribes nigrum L.) Namen magistrske naloge je bil ugotoviti, kako osvetljevanje s svetlobo svetlečih diod in/ali tretiranje ribeza z vročo vodo vpliva na kemijsko sestavo in CIE barvnih parametrov L*, a*, b* črnega ribeza. Črni ribez je bil tretiran z vročo vodo, s temperaturo 50 °C, 4 min in/ali izpostavljen UV-B svetlobi (310 nm) ter modri svetlobi (444 nm), 21 dni pri 0,5 °C. Netretirani vzorci so bili shranjeni 21 dni na 0,5 °C. Vzorcem črnega ribeza smo določali antioksidativni potencial (AOP) z metodo prostega radikala DPPH˙, vsebnost skupnih fenolnih spojin s Folin-Ciocalteu reagentom in skupnih flavonoidov z AlCl3. Barvo kožice plodov smo merili s kromametrom Minolta in s sistemom CIE L* a* b*. Rezultati analiz so pokazali trend naraščanja AOP, skupnih fenolov in skupnih flavonoidov. Največji vpliv na spremembo AOP, skupnih fenolov in flavonoidov v ribezu je imela modra svetloba. Prav tako je imela modra svetloba največji vpliv na spremembe barvnih parametrov L*, a*, b*, C* in h°. Vzorci, izpostavljeni UV-B svetlobi in hkrati tretirani z vročo vodo, so se statistično razlikovali od z vročo vodo netretiranih kontrolnih vzorcev in netretiranih vzorcev osvetljevanih z UV-B svetlobo. Tretiranje z vročo vodo je pokazalo trend zaviranja sinteze skupnih fenolov in flavonoidov. The purpose of the master’s thesis was to determine the effect of light-emitting diodes irradiation and/or hot water dipping (HWT) on the chemical composition and CIE colour L*, a*, b* parameters of black currant. Black currant was treated with hot water at 50 °C for 4 min and/or exposed to UV-B (310 nm) and blue LEDs (444 nm) for 21 days at 0,5 °C. Non-treated control was also stored at 0,5 °C for 21 days. The following analyses were carried out before and during treatments: antioxidant potential (AOP) was determined using DPPH˙ radical, content of phenolic compounds with Folin-Ciocalteu assay and total flavonoid content with AlCl3. The fruit colour was measured using Chroma Meter Minolta and the CIE L*, a*, b* system. The results showed a trend of an increase of the AOP, total phenolic and flavonoid content for all treatments during 21-day storage period. Blue light irradiation resulted in the highest increase of AOP, total phenolics and flavonoids as well as changes in colour parameters (L*, a*, b*, C* and h°). Only the samples treated with HWT and illuminated with UV-B differed significantly from non-treated control and non-treated UV-B. HWT showed trend to retard the synthesis of phenols and flavonoids. črni ribez Ribes nigrum L. svetloba osvetljevanje svetleče diode LED antioksidativni potencial fenolne spojine flavonoidi kromameter CIELAB sistem black currant Ribes nigrum L. light lighting light-emitting diodes LED antioxidant potential phenolic compounds flavonoids Chroma Meter CIELAB system true false false [M. Bahor] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2019-10-31 07:45:03 2019-10-31 07:45:06 2022-08-24 03:52:17 0000-00-00 00:00:00 2019 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 634.732:547.56:66.094.3.097.8:577.1 174929 5117560 8607.pdf 8607.pdf 1 5152652D04B46001D4C981CAAB931C47 d0a893b58c9da3778c038534bac6521ae09a978893e9e0dbfbc61756fd3e3600 eeb7620c-a1b7-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=124591 Biotehniška fakulteta 0 0 0