20.500.12556/DKUM-69767 Antioksidativni potencial plodov različnih genotipov malinjaka (Rubus idaeus L.) Antioxidant Activity of Different Raspberry Fruit Genotypes (Rubus idaeus L.) Maline so bogat vir antioksidantov, med katere spadajo rastlinski sekundarni metaboliti. Te spojine preprečujejo oksidacijo plodov, do katere lahko pride zaradi vpliva okolijskih dejavnikov in delovanja mikroorganizmov. Namen naloge je bil raziskati vpliv genotipa malinjaka (Rubus idaeus L.), sušenja svežih plodov z zamrzovanjem in toplotne obdelave plodov pri pripravi nektarja na antioksidativni potencial. V raziskavo smo vključili plodove 19 različnih genotipov malinjaka. Antioksidativni potencial v metanolnih ekstraktih svežih in posušenih plodov ter nektarja smo merili z ABTS-, DPPH-, FRAP- in ORAC-metodami. Rezultate smo podali v µmol Trolox ekvivalenta (TE)/g suhe snovi (SS). Najvišji antioksidativni potencial je bil izmerjen pri divjem genotipu malinjaka, sledili so še primitivni in kultivirani genotipi. V ekstraktih plodov, ki so bili sušeni z zamrzovanjem, so bile ABTS-, DPPH- in FRAP-vrednosti višje kot v ekstraktih svežih plodov, vrednosti ORAC pa so pokazale drugačen trend. V ekstraktih nektarja so bile ABTS-, DPPH- in FRAP-vrednosti nižje kot v ekstraktih svežih plodov. Znižanje antioksidativnega potenciala med termično obdelavo je lahko posledica izgube naravno prisotnih antioksidantov. Antioksidativni potencial ekstraktov svežih plodov, izmerjen z ABTS-metodo, močno in značilno korelira z vrednostmi, izmerjenimi z DPPH- in FRAP-metodo. Med ORAC-, ABTS-, FRAP- ali DPPH-vrednostmi ni značilne korelacije. Raspberries are a good source of antioxidant molecules. These compounds are a group of secondary metabolites that prevent the fruit from oxidation due to environmental factors and microbiological attacks. The objective of this investigation was to evaluate the effects of raspberry genotype (Rubus idaeus L.), freeze-drying and thermal treatment on antioxidant activity. Fruits of 19 different raspberry genotypes were included in our investigation. Antioxidant activity was measured in metanolic extracts of fresh and liophilized berries and in extracts prepared from nectar using ABTS, DPPH, FRAP and ORAC assays. The results were expressed in μmol of Trolox equivalent (TE)/g of dry matter (SS). The highest antioxidant activity occurred in the wild genotype, followed by the primitive and cultivated genotypes. The ABTS, DPPH and FRAP values for the extracts of freeze-dried fruits were higher than their values for the extracts of fresh fruits. ORAC values showed the opposite trend. The ABTS, DPPH and FRAP values for the extracts of nectar were lower than for the extracts of fresh fruits. Reduction of the antioxidant activity during thermal treatment could be due to the loss of naturally occurring antioxidants. The ABTS values for the extracts of fresh fruits showed strong and significant correlation with DPPH and FRAP values. No correlations were observed between ORAC and ABTS, FRAP or DPPH values. malinjak (Rubus idaeus L.) antioksidativni potencial sveži plodovi plodovi sušeni z zamrzovanjem nektar raspberry (Rubus idaeus L.) antioxidant activity fresh sample freeze-dryed sample nectar true true false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2018-02-22 22:05:53 2018-03-09 08:54:22 2022-08-01 18:08:35 2019-07-11 17:43:28 2018 0 Maribor 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 URN:SI:UM:DK:HPJTB8WX MAG_Breznik_Anita_2018.pdf MAG_Breznik_Anita_2018.pdf 1 FD8EC54CADF022A1B499809186A1A000 0f1737d98ea0b1865a070b4cfd0f4d17c0175fce53ae07fd22dd019406ede1b7 af61e301-7c0f-11eb-bb7a-00155d0001ca 20.500.12556/dkum/c8cce183-ee83-4cc0-ab14-dd3349c6ed6e https://dk.um.si/Dokument.php?lang=slv&id=122223 Fakulteta za kmetijstvo in biosistemske vede 0 0 0