Promjene udjela metilksantina i polifenola tijekom šestomjesečnog skladištenja čokoladnih likera

master's thesis

• Title (english): Changes in the compositions of methylxantines and polyphenols in chocolate liquers during six months of storage
• Author: Iva Finderle
• Mentor: Draženka Komes (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Chemistry and Technology of Carbohydrates and Confectionery Products); Zagreb
• Defense date and country: 2014-02-25, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Nutrition

Abstract

U skladu s povećanim interesom za funkcionalne prehrambene proizvode, i čokoladni likeri, zbog svog zanimljivog bioaktivnog sastava, postaju zanimljiv predmet znanstvenih istraživanja. Čokolada, kao dobar izvor polifenola i metilksantina, i etanol, kao učinkovito otapalo za njihovu ekstrakciju, dobra su polazna točka za proizvodnju ovih potencijalno funkcionalnih proizvoda. Cilj istraživanja bio je odrediti promjenu sastava polifenola i metilksantina u čokoladnim likerima proizvedenima od čokolada različitih udjela kakaovih dijelova (30, 32, 50 i 72%) u kombinaciji s različitim udjelima etanola (20, 25 i 30 % vol.) tijekom šestomjesečnog skladištenja. Udjeli polifenola ((-)-epikatehin, (+)-katehin, procijanidin B2, protokatehinska kiselina) i metilksantina (teobromin i kafein) određeni su tekućinskom kromatografijom visoke djelotvornosti (HPLC-PDA). Teobromin je bio dominantan metilksantin, dok su među polifenolnim spojevima određeni (-)-epikatehin, (+)-katehin, procijanidin B2 i protokatehinska kiselina, čiji su udjeli varirali ovisno o sastavu likera. Čokoladni liker pripremljen s čokoladom koja sadrži 72% kakaovih dijelova u kombinaciji s 30%-tnim etanolom sadržavao je najveći udjel svih bioaktivnih spojeva i zadržao stabilnost tijekom svih šest mjeseci skladištenja.

Abstract (english)

With the increasing interest for functional products, chocolate liqueurs, due to their interesting bioactive composition, are becoming an interesting subject in scientific research. Chocolate, as good source of polyphenols and methylxantines, and ethanol, as an effective solvent for their extraction, are a good starting point for production of a potential functional products. The aim of this research was to determine changes in the composition of polyphenols and methylxantines in chocolate liqueurs produced from chocolates with different cocoa solids content (30, 32, 50 and 72%) in combination with different concentrations of ethanol (20, 25 and 30% vol.) during six months of storage. Contents of polyphenols ((-)-epicatechin, (+)-catechin, procyanidin B2, protocatechuic acid) and methylxanthines (theobromine and caffeine) were determined by high-performance liquid chromatography (HPLC-PDA). Theobromine was a dominant methylxanthine, while among polyphenolic compounds, the shares of (-)-epicatechin, (+)-catechin, procyanidin B2 and protocatechuic acid depended on the composition of the liqueur. Chocolate liqueur prepared with the chocolate containing 72% cocoa solids in combination with 30% ethanol was proven to have the highest amount of bioactive compounds, and the best sustainability during six months of storage.

• Keywords: čokoladni likeri; ekstrakcija; HPLC; metilksantini; polifenoli
• Keywords (english): chocolate liqueurs; extraction; HPLC; methylxanthines; polyphenols
• Language: croatian
• URN:NBN: urn:nbn:hr:159:058717
• Study programme: Title: Nutrition; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra nutricionizma (magistar/magistra nutricionizma)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-04-28 12:05:45