Določanje polifenolnih komponent in njihovih antioksidativnih lastnosti v različnih vrstah medu

diplomsko delo univerzitetnega študijskega programa I. stopnje

Miša Žnidarič (Avtor), Petra Kotnik (Mentor), Maša Knez Hrnčič (Komentor)

Povzetek

Med je naravno živilo, ki se že stoletja uporablja v prehrani, danes pa postaja vedno bolj priljubljeno zaradi svojih zdravilnih lastnosti, ki jih ima na telo. Razlog za povečano povpraševanje po medu je visoka vsebnost fenolnih spojin in njihovih antioksidativnih lastnosti. V diplomski nalogi smo preverili, kakšna je vsebnost bioaktivnih komponent v različnih vrstah medu. Z uporabo maceracije, ultrazvočne ekstrakcije in ekstrakcije na trdni fazi smo izolirali fenolne spojine. Zanje velja, da v telesu v kombinaciji z drugimi biološko aktivnimi spojinami delujejo antioksidativno, antidiabetično, protimikrobno, protivnetno ter preprečujejo nastanek in razvoj rakavih celic. Pripravljenim vzorcem medu smo spektrofotometrično določili vsebnost celokupnih fenolov, flavonoidov in ogljikovih hidratov ter preverili antioksidativno aktivnost z DPPH, FRAP in CUPRAC metodo. S pomočjo tekočinske kromatografije z masno spektrometrijo (LC-MS/MS) smo kvantitativno in kvalitativno določili vsebnost osmih fenolnih spojin v vzorcih medu. V diplomski nalogi smo iz medu uspešno izolirali fenolne spojine in potrdili hipotezo, da se vsebnosti fenolnih spojin razlikujejo glede na vrsto medu. Ugotovili smo, da število skupnih fenolnih spojin vpliva na antioksidativno učinkovitost, saj so vzorci z višjo vsebnostjo celokupnih fenolov izkazovali boljše antioksidativne lastnosti. Uporabili smo več testov antioksidativnosti, s katerimi smo dobili slabo primerljive rezultate, saj se metode razlikujejo po mehanizmih delovanja. V metanolnih vzorcih medu smo določili najvišji delež kavne kisline in katehina, v nakisanih vzorcih pa je prevladovala tudi galna kislina. V vzorcih za čiščenje fenolnih spojin smo zaznali le elagno kislino, v očiščenih vzorcih pa največ elagne kisline in katehina. Potrdimo lahko hipotezo, da je med zaradi svoje sestave zelo kompleksen medij za izolacijo fenolnih komponent, saj sladkorji in druge komponente v medu motijo določitev fenolnih spojin.

Ključne besede

med;fenolne spojine;antioksidativna aktivnost;testi antioksidativnosti;diplomske naloge;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2022
Tipologija:	2.11 - Diplomsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[M. Žnidarič]
UDK:	547.562:638.162(043.2)
COBISS:	130924803
Št. ogledov:	98
Št. prenosov:	38
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Determination of polyphenolic components and their antioxidant properties in different types of honey
Sekundarni povzetek:	Honey is a natural foodstuff, which has been used in nutrition for centuries, but today it is becoming even more popular due to its medicinal properties and effects on the body. The reason for increased demand for honey is its high content of phenolic compounds and their antioxidant properties. In this paper, we studied the content of bioactive components in different types of honey. Using maceration, ultrasound extraction and solid-phase extraction, we isolated phenolic compounds. In combination with other biological active compounds in the body, not only do they have antioxidant, antidiabetic, antimicrobial and anti-inflammatory effects, but they also prevent the formation and development of cancer cells. We conducted a spectrophotometric analysis to determine the content of total phenols, flavonoids and carbohydrates in the prepared samples of honey, studying also the antioxidant activity with the DPPH, FRAP and CUPRAC methods. Using liquid chromatography-mass spectrometry (LC-MS/MS), we conducted a quantitative and qualitative analysis of honey samples to determine the content of eight phenolic compounds. In this paper, we managed to isolate phenolic compounds from honey and confirmed a hypothesis stating that the contents of phenolic compounds differ based on the type of honey. We determined that the number of total phenolic compounds affect antioxidant efficiency, as samples with a higher content of total phenols had better antioxidant properties. We did a number of antioxidant activity tests, yet their results had reduced comparability, as certain methods differed based on their mechanisms of action. The highest content of caffeic acid and catechin was determined in methanolic samples of honey, and gallic acid was proved to be predominant in acidified samples. In the samples used for cleaning phenolic compounds, we detected only the ellagic acid, and we found the highest content of ellagic acid and catechin in clean samples. We can thus confirm the hypothesis that, due to its composition, honey is a very complex medium for the isolation of phenolic components, as sugars and other components in honey hinder the determination of phenolic compounds.
Sekundarne ključne besede:	honey;phenolic compounds;antioxidant activity;LC-MS/MS;antioxidant activity test;
Vrsta dela (COBISS):	Diplomsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	1 spletni vir (1 datoteka PDF (XI, 88 f.))
ID:	16204806