20.500.12556/RUL-180507 Uporaba hlapnih prekurzorjev arom za izboljšanje primarne in sekundarne arome jabolk med skladiščenjem Application of volatile aroma precursors to enhance primary and secondary aroma of apples during storage V doktorski nalogi smo raziskovali vpliv hlapnih prekurzorjev arom na regulacijo biosinteznih poti hlapnih spojin v jabolkih. Z uporabo plinske kromatografije, sklopljene z masno spektrometrijo (GC-MS), smo analizirali učinke skladiščenja izbranih sort jabolk ('Granny Smith', 'Gala', 'Fuji Kiku', 'Braeburn') v nadzorovanih atmosferah, obogatenih s heksanalom, etanolom, 1-butanolom in 2-metil-1-butanolom. Ugotovili smo, da je nastanek hlapnih spojin iz prekurzorjev odvisen od koncentracije, časa in temperature. Dodatek heksanala je selektivno spodbudil sintezo heksil acetata pri vseh sortah, medtem ko je imel etanol najpomembnejši vpliv na tvorbo 2-metilbutil acetata in etil 2-metilbutanoata pri sorti 'Gala'. Višje koncentracije prekurzorjev so bolj selektivno vplivale na povečano produkcijo estrov, medtem ko so nižje koncentracije spodbudile produkcijo širšega spektra hlapnih spojin pri sorti 'Fuji Kiku'. Z analizo vrednosti vonjalne aktivnosti (angl. odor activity value, OAV) smo pokazali, da dodatek prekurzorjev pomembno prispeva k povečanju arome, pri čemer sami prekurzorji ne vplivajo pomembno na aromatični profil jabolk sorte 'Gala'. Kombinacija etanola in 1-butanola ni bistveno povečala biosinteze estrov v primerjavi z individualno aplikacijo alkohola. Povečano vsebnost estrov in alkoholov, kot so heksil acetat, 2-pentanol in 2-pentanon, smo potrdili tudi v jabolčnem soku sort 'Braeburn' in 'Granny Smith' po skladiščenju v atmosferah z etanolom ali heksanalom. V soku, pridobljenem iz mesa 'Fuji Kiku' po skladiščenju v atmosferi z dodatkom heksanala, smo določili večje količine estrov, vključno z 2-metilbutil acetatom, butil in heksil acetatom, s čimer smo potrdili, da prekurzor prodira v notranjost plodu, kjer se presnavlja v spojine, pomembne za aromo jabolk. Z uporabo z devterijem označenih prekurzorjev smo dodatno potrdili, da prekurzorji vplivajo na presnovne poti ne le kot substrati, temveč tudi kot regulatorji biosinteze hlapnih aromatičnih spojin. As part of the dissertation, we investigated the influence of volatile aromatic precursors on the regulation of biosynthetic pathways of volatile compounds in apples. Using gas chromatography coupled with mass spectrometry (GC-MS), we analysed the effects of storing selected apple varieties ('Granny Smith', 'Gala', 'Fuji Kiku', 'Braeburn') in controlled atmospheres enriched with hexanal, ethanol, 1-butanol, and 2-methyl-1-butanol. We found that the formation of volatile compounds from precursors depends on concentration, time, and temperature. The addition of hexanal selectively stimulated the synthesis of hexyl acetate in all varieties, while ethanol had the most significant effect on the formation of 2-methylbutyl acetate and ethyl 2-methylbutanoate in the 'Gala' variety. High concentrations of precursors more selectively increased ester production, whereas lower concentrations stimulated the production of a wider range of volatile compounds in 'Fuji Kiku'. Analysis of odor activity values (OAV) showed that the addition of precursors contributed to increased aroma, while the precursors themselves did not affect the aroma profile of 'Gala' apples. The combination of ethanol and 1-butanol did not increase ester biosynthesis compared to the individual application of the alcohols. Increased contents of esters and alcohols such as hexyl acetate, 2-pentanol, and 2-pentanone were also found in the apple juice of 'Braeburn' and 'Granny Smith' after storage in an atmosphere containing ethanol or hexanal. Higher amounts of esters, including 2-methylbutyl acetate, butyl and hexyl acetate, in juice from 'Fuji Kiku' flesh after storage in an atmosphere with added hexanal confirmed that the precursor penetrates into the interior of the fruit, where it is converted into compounds important for apple aroma. The use of deuterium-labelled precursors also confirmed that precursors influence metabolic pathways not only as substrates but also as regulators of the biosynthesis of volatile aromatic compounds. hlapne aromatične spojine aroma jabolk hlapni prekurzorji primarna aroma sekundarna aroma estri hidrolati arom naravna aroma volatile aromatic compounds apple aroma volatile precursors primary aroma secondary aroma esters aroma hydrolates natural aroma true false false [E. Jesenko] Slovenski jezik Angleški jezik Doktorsko delo/naloga 2026-03-11 07:16:48 2026-03-11 07:16:56 2026-03-12 09:55:38 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 664.8.037:634.11:547.52 279085 271366403 56349.pdf 56349.pdf 1 556DD03194E0BB3DE1CB72FE1986D42D a50a8761c283188324958164660bc0b59dfca3350eb3fd3bae90c9cccf396464 832fecc6-1d11-11f1-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=229958 Biotehniška fakulteta 0 0 0