The polyphenols and methylxanthines analysis in different samples of cocoa liquor

master's thesis

• Title: Analiza polifenolnih spojeva i metilksantina u kakao masi različita podrijetla
• Author: Iva Barbaroša
• Mentor: Jasna Vorkapić-Furač (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); Zagreb
• Defense date and country: 2005-10-27, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Mnoga istraživanja pokazuju da su kakao zrno i proizvodi dobiveni iz kakao zrna, kao što su kakao masa, kakao prah i ukusna čokolada, bogati antioksidansima. Antioksidansi štite ljudski organizam od slobodnih radikala i na taj način sprečavaju nastajanje karcinoma i koronarnih bolesti. Analiziran je udio ukupnih masti i minerala u uzorcima kakao mase različita podrijetla. U svim uzorcima postotak ukupne masti je oko 52 %. Minerali su analizirani plamenom atomskom apsorpcijskom spektrofotometrijom (FAAS) te je utvrđeno da najviše ima Fe, a najmanje Ca. U radu je pozornost usmjerena prema tekućinskoj kromatografiji obrnutih faza (RP-LC) kojom se uspješno razdvajaju monomerni polifenolni spojevi i metilksantini. Analizirani su polifenoli [(-)-epikatehin, (+)-katehin, (-)-epigalokatehin, (+)-galokatehin, kava kiselina i kumarinska kiselina] i metilksantini (teobromin i kafein) u sedam uzoraka kakao mase. Na kromatogramima je razdijeljeno više od 30 pikova, od kojih su pomoću UV-spektara identificirani gore navedeni spojevi. Najzastupljeniji je metilksantin teobromin, a od polifenola kava kiselina, (+)-galokatehin i (-)-epikatehin.

Abstract (english)

A lot of investigation show that the cocoa bean, and products derived from the cocoa bean such as cocoa liquor, cocoa powder and tasty chocolate, are rich in specific antioxidants. These compounds protect human organism from free radicals, thus inhibiting the appearance of coronary heart diseases and cancer. The research objectives stated above were accomplished by measuring the total fats and minerals in different cocoa liquor samples. The percentage of total fat in all the samples is about 52 %. FAAS-method was used for the identification of minerals. Based on the outcome of all the measurements it can be concluded that amount of Fe was the highest, and on the other hand amount of Ca was the smallest in all samples. In this study the reversed-phase liquid chromatography (RP-LC) was used for polyphenol and methylxanthine separations. HPLC method was used for analysing polyphenols [(-)-epicatechin, (+)-catechin, (-)-epigallocatechin, (+)-gallocatechin, coffeic acid and coumaric acid] and methylxanthines (theobromine and caffeine) in seven chocolate samples. The chromatograms have more then thirty well separated peaks, thus polyphenols and methylxanthines were identified by UV-spectra. Most present methylxanthine is theobromine and most present polyphenols are caffeic acid, (+)-gallocatechin and (-)-epicatechin.

• Keywords: kakao masa; metilksantini; polifenoli; tekućinska kromatogrfija visoke djelotvornosti
• Keywords (english): cocoa liquor; high performance liquid chromatography; methylxanthines; polyphenols
• Language: croatian
• URN:NBN: urn:nbn:hr:159:256979
• Study programme: Title: Biotehnologija; smjerovi: Biokemijsko inženjerstvo; Study programme type: sveučilišni; Study level: dodiplomski; Academic / professional title: diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo (diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Restricted access
• Created on: 2017-09-11 10:14:19