Utjecaj procesa preradbe sirovog kakao zrna na polifenolne spojeve i njihov antioksidacijski kapacitet

master's thesis

• Title (english): The effect of processing raw cocoa seeds on polyphenol composition and their antioxidant capacity
• Author: Tanja Županić
• Mentor: Karmela Delonga (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; Zagreb
• Defense date and country: 2008-12, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Kakao zrno sadrži mnoštvo polifenolnih spojeva među kojima prevladavaju monomerni i oligomerni flavan-3-oli. Tijekom preradbe sastav i udjeli polifenola mijenjaju se, posebice pri fermentaciji i sušenju fermentiranog zrna. Daljnjom preradbom zrna, koja se odvija u našim tvornicama, primjenjuju se povišene temperature koje uzrokuju snižavanje udjela polifenola. U radu su istraženi uzorci različitih stupnjeva preradbe kakao zrna i utjecaj preradbe na udio ukupnih polifenolnih spojeva i njihov antioksidacijski kapacitet. U metanolnim ekstraktima odmašćenih uzoraka ukupni su polifenoli analizirani spektrofotometrijskom metodom s Folin-Ciocalteau reagensom. Antioksidacijska aktivnost hidrofilnih i lipofilnih uzoraka iz preradbe te čokolada različitog postotka kakaa analizirana je spektrofluorimetrijskom ORAC metodom. Sirovo kakao zrno, koje ima najveću koncentraciju polifenola (15,21 mg g-1), ima i najvišu ORAC vrijednost (266,10 μmol TE g-1). Utvrđeno je da su vrijednosti ORAC-a za lipofilne uzorke puno niže od onih za hidrofilne. Uzorci tamnih čokolada koji imaju najviši postotak čokolade (88%) imaju i najvišu ORAC vrijednost.

Abstract (english)

Cocoa seeds contain a multitude of polyphenol compounds, majority of which are monomer and oligomer variants of flavan-3-ols. During processing, the composition and ratios of polyphenols change, especially during fermentation and the drying of fermented seeds. Further processing of the seeds, which is done in our factories, applies heightened temperatures that cause the lowering of the ratio of polyphenols. The research explores samples of varying degree of processing of the cocoa seeds and the effect the processing has on ratio of polyphenol compounds and their antioxidant capacity. In the research, a spectrophotometric method with Folin-Ciocalteau reagent is used to determine total polyphenol count in methanol-based extracts of defatted cocoa masses. Antioxidant activity of hydrophilic and lipophilic samples of cocoa masses and chocolates of various cocoa percentages was analyzed with the spectrofluorimetric ORAC method. Raw cocoa bean with the largest concentration of polyphelnols (15,21 mg g-1), has the highest ORAC value as well (266,10 μmol TE g-1). It has been found that ORAC values of lipophilic samples are much lower than those of hydrophilic ones. The samples of dark chocolate with the highest chocolate percentage (88%) have the highest ORAC value as well.

• Keywords: antioksidacijska aktivnost; kakao zrno; kakao masa; ORAC-metoda; polifenoli
• Keywords (english): antioxidative activity; cocoa bean; cocoa liquor; ORAC method; polyphenols
• Language: croatian
• URN:NBN: urn:nbn:hr:159:775837
• Study programme: Title: Biotechnology; specializations in: Biochemical Engineering; Course: Biochemical Engineering; Study programme type: university; Study level: graduate; 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: Access restricted to students and staff of home institution
• Created on: 2017-08-31 11:18:48