| Abstract | Glukozinolati su specijalizirani biljni metaboliti pronaĎeni u 16 različitih biljnih porodica reda Brassicales. Po kemijskoj strukturi su β-tioglukozidni-N-hidroksisulfati s promjenjivim bočnim lancem koji se biosintetizira iz aminokiselina. Glukozinolati su kemijski i biološki neaktivni spojevi, čijom enzimskom, termičkom ili kemijskom razgradnjom nastaju izotiocijanati, izocijanati, nitrili i drugi spojevi. Razumijevanje stabilnosti glukozinolata u uvjetima koji oponašaju obradu namirnica je važno budući da su ovi spojevi zastupljeni u hrani koja se svakodnevno konzumira (kupus, brokula, rotkva, gorušica...). U ovom radu promatrana je stabilnost glukozinolata iz sjemena bijele gorušice i daikona u uvjetima mikrovalnog zračenja. Primijenjene su različite snage mikrovalova: 500, 800 i 1200W. Glukozinolati su kvalitativno i kvantitativno analizirani koristeći UHPLC-DAD-MS/MS. Uzorak bijele gorušice nakon izlaganja snazi mikrovalova od 1200 W, ekstrahiran je diklormetanom u svrhu izolacije razgradnih produkata glukozinolata, koji su naposljetku identificirani korištenjem GC-MS tehnike. U bijeloj gorušici identificirani su epiprogoitrin, glukosinalbin, 4-hidroksiglukobrasicin i glukobrasicin, dok su u sjemenu daikona identificirani glukorafanin, glukorafenin, 4-hidroksiglukobrasicin i 4- metoksiglukobrasicin. Identificirana su 3 produkta razgradnje glukozinolata koji potječu od glukosinalbina: 4-hidroksibenzenil- izotiocijanat, 2-(4-hidroksifenil)acetonitril, 5-vinil-1,3-oksazolidin-2-tion. Iz dobivenih je rezultata vidljivo da je primjenom veće snage mikrovalova koncentracija identificiranih glukozinolata sve manja. Najveću koncentraciju glukozinolata ima sjeme koje nije izloženo mikrovalovima, dok najmanju koncentraciju glukozinolata ima sjeme izloženo mikrovalovima snage 1200W. |
| Abstract (english) | Glucosinolates are specialized plant metabolites found in 16 different plant families of the order Brassicales. They have a chemical structure of β-thioglucoside-N-hydroxysulfates with a variable side chain synthesized from amino acids. Glucosinolates are chemically and biologically inactive compounds, which upon enzymatic, thermal, or chemical degradation, give isothiocyanates, thiocyanates, nitriles, and other compounds. Understanding the stability of glucosinolates under conditions simulating food processing is important as these compounds are present in commonly consumed foods such as cabbage, broccoli, radish, and mustard. This thesis examined the stability of glucosinolates from white mustard and daikon seeds exposed to microwave radiation. Different microwave powers were applied: 500, 800, and 1200W. Glucosinolates were qualitatively and quantitatively analyzed using UHPLC-DAD-MS/MS. The white mustard sample, after exposure to 1200W microwave power, was extracted with dichloromethane to isolate degradation products of glucosinolates, which were ultimately identified using GC-MS technique. Glucosinolates identified in white mustard were epiprogoitrin, glucosinalbin, 4-hydroxyglucobrassicin, and glucobrassicin, while in daikon seeds the identified glucosinolates were: glucoraphanin, glucoraphenin, 4-hydroxyglucobrassicin, and 4-methoxyglucobrassicin. Three glucosinolate degradation products originating from glucosinalbin were identified: 4- hydroxybenzyl isothiocyanate, 2-(4-hydroxyphenyl)acetonitrile, and 5-vinyl-1,3-oxazolidin-2-thione. From the obtained results, it is evident that higher microwave power leads to decreasing concentrations of identified glucosinolates. The highest concentration of glucosinolates is found in seeds not exposed to microwaves, while the lowest concentration is in seeds exposed to 1200W microwave power. |
