Določanje maščobnih kislin v pekovskih izdelkih s plinsko kromatografijo

Novak, Melita (author), Prosen, Helena (mentor)

Namen mojega diplomskega dela je bil določanje celokupne vsebnosti maščobnih kislin v pekovskih izdelkih s slovenskega in srbskega tržišča ter ugotavljanje vsebnosti trans-maščobnih kislin. Na slovenskem trgu je najvišja dovoljena vsebnost trans-maščobnih kislin na 2 g na 100 g celokupnih maščob. Primerjala sem ekstrakcijo maščobe z Weibull-Stoldt-ovo metodo in metodo z uporabo MAK174 pribora. Delež ekstrahirane maščobe pri Weibull-Stoldt-ovi metodi je okoli 25 % (m/m), pri uporabi MAK174 pribora pa povprečno 10 % (m/m). Vzorce sem analizirala s plinsko kromatografijo s plamensko-ionizacijskim detektorjem. Priprava ekstrakta za GC-FID analizo vključuje derivatizacijo ekstrahirane maščobe iz vzorca v hlapne metilne estre maščobnih kislin. Analiza je potekala na močno polarni koloni HP-88, kjer so se metilni estri maščobnih kislin ločili glede na dolžino verige, nenasičenost, cis/trans izomerizacijo in pozicijo dvojne vezi. Spojine v vzorcih sem identificirala glede na retencijske čase pri predhodno optimizirani kromatografski metodi, ki omogoča ustrezno ločbo C18:2 in C18:3 maščobnih kislin. Kvantitativna določitev, ki vključuje tudi pripravo vzorca, ima visoko ponovljivost.

• Language: Slovenian
• Keywords: plinska kromatografija, maščobne kisline, metilni estri, pekovski izdelki
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2020
• PID: 20.500.12556/RUL-117462
• COBISS.SI-ID: 23473667
• Publication date in RUL: 10.07.2020

NOVAK, Melita, 2020, Določanje maščobnih kislin v pekovskih izdelkih s plinsko kromatografijo [online]. Bachelor’s thesis. [Accessed 1 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=117462

Secondary language

• Language: English
• Title: Determination of fatty acids in bakery products by gas chromatography

Abstract

The aim of this thesis is the determination of total fatty acid content in bakery products from Slovenian and Serbian market and quantification of trans-fatty acids. The maximum amount of trans-fatty acids on Slovenian market is 2g per 100 g of total fat content. Two fat extraction methods were compared: Weibull-Stoldt method and extraction by MAK174 kit. The Weibull-Stoldt method gives approximately 25 % (m/m), while MAK174 kit only allows extracting 10 % (m/m) on average. The samples were analysed by gas chromatography with flame-ionization detector. Extract preparation for GC-FID analysis includes derivatization of extracted fat from a sample to volatile methyl esters of fatty acids. The analysis was performed on a highly polar HP-88 column, which allows separation of fatty acid methyl esters according to the length of chain, unsaturation, cis/trans isomerization and the double bond position. Compounds in the samples were identified based on retention times acquired with a previously optimized chromatographic method, which allows a better separation of C18:2 and C18:3 fatty acids. Quantitative determination, which includes sample preparation as well, has a great repeatability.

• Keywords: gas chromatography, fatty acids, methyl esters, bakery products