Določanje biorazpoložljivega železa v prehranskih dopolnilih

Stojanoska, Izabela (author), Kočar, Drago (mentor)

Železo je element, ki je bistven za človeško telo. Sodeluje v številnih presnovnih procesih in tako omogoča normalno delovanje telesa. Ker železo dobimo v telo s hrano, dnevne potrebe po njem v telesu niso vedno dosežene. Da bi se izognili pomanjkanju železa v krvi in s tem pojavu anemije, se kot prehransko dopolnilo uporablja laboratorijsko sintetizirana oblika železa. Ta prehranska dopolnila so komercialno na voljo v obliki tablet, šumečih tablet, kapsul in tekočine.Namen magistrskega dela je bilo ugotoviti vsebnostbiorazpoložljivega železa v petih različnih prehranskih dopolnilih. V ta namen se železo, ki ga najdemo v prehranskih dopolnilih, raztopi v različnih koncentracijah šibkih kislin ob prisotnosti nekaterih ligandov, ki se lahko nahajajo v hrani. Kisline, ki sem jih uporabljala za raztapljanje, so bile: ocetna, citronska, mravljinčna, oksalna in vinska kislina. Izvedla sem tudi dodatno raztapljanje prehranskih dopolnil v različnih ligandih – fitinski kislini in EDTA. Meritve vsebnosti železa sem opravila z AAS in določena je bila vsebnost sproščenega železa v takih pogojih. Celotno vsebnost železasem določila z raztapljanjem prehranskega dopolnila v močni kislini (HCl, HNO3, H2SO4, H3PO4). Raztapljanje prehranskih dopolnil v vseh zgoraj omenjenih kislinah in ligandihpotekala v dveh serijah, in sicer: prva serija -raztapljanje v ultrazvočni kopeli, to je raztapljanje pri sobni temperaturi, in druga serija raztapljanje s segrevanjem do vrenja, tj. raztapljanje pri povišani temperaturi. Izvedla sem tudi analizo prisotnosti Fe(II) in Fe(III) ionov in določilanjihovo vsebnost z 1,10-fenantrolinom. Meritve sem opravila z UV-Vis spektofotometrom pri valovni dolžini 511nm. Glede nadobljene rezultate sem ugotovila, da imata dva vzorca približno enako biorazpoložljivost železa v vseh kislinah, ki smo jih uporabili za analizo, medtem ko je v ostalih treh biorazpoložljivost železa odvisna od vrste kisline in se z nižanjem koncentracij kisline zmanjšuje. Iz rezultatov analize Fe(II) in Fe(III)ionov je razvidno, da je v vseh vzorcih prisoten Fe(II) ion, kot je navedeno na njihovi deklaraciji.

• Language: Slovenian
• Keywords: biorazpoložljivo železo, prehranska dopolnila, organske kisline, ligandi, AAS
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2022
• PID: 20.500.12556/RUL-138060
• COBISS.SI-ID: 117043971
• Publication date in RUL: 08.07.2022

Secondary language

• Language: English
• Title: Determination of bioavailable iron in dietary supplements

Abstract

Iron is an element that is essential for the human body. It participates in many metabolic processes and thus enables the body to function normally. Since we get iron in the body through food, the daily needs for it in the body are not always reached. In order to avoid a lack of iron in the blood and thus the appearance of anemia, a laboratory-synthesized form of iron is used as a dietary supplement. These dietary supplements are commercially available in tablets, effervescent tablets, capsules, and liquid form. The purpose of the Master's thesis was to determine the content of bioavailable iron in five different dietary supplements. For this purpose, the iron found in food supplements is dissolved in various concentrations of weak acids in the presence of certain ligands that may be found in food. The used acids for dissolution were: acetic, citric, formic, oxalic, and tartaric acids. Also an additional dissolution of nutritional supplements in different ligands - phytic acid and EDTA were performed. The iron contentwas measured with AAS and the content of released iron was determined under such conditions. The total iron content was determined by dissolving the dietary supplement in strong acid (HCl, HNO3, H2SO4, H3PO4). The dissolution of nutritional supplements in all the above-mentioned acids and ligands took place in two series, namely: the first series - dissolution in an ultrasonic bath, i.e. dissolution at room temperature, and the second series - dissolution by heating to boiling, i.e. dissolution at elevated temperature. The presence of Fe(II) and Fe(III) ions and determined their content with 1,10-phenanthroline was also analized. The measurements with a UV-Vis spectrophotometer were performed ata wavelength of 511 nm. According to the obtained results, for two samples were found that they have approximately the same bioavailability of iron in all the acids used for analysis, while in the other three, the bioavailability of iron depends on the type of acid and decreases with decreasing acid concentrations. From the results of the analysis of Fe(II) and Fe(III) ions, it can be seen that Fe(II) ion is present in all samples, as stated in their declaration.

• Keywords: bioavailable iron, dietary supplements, organic acids, ligands, AAS