Utjecaj tromjesečnog odležavanja na polifenolni sastav i reološka svojstva čokoladnih likera

master's thesis

• Title (english): Influence of three months of storage on the content of polyphenols and the rheological properties of chocolate liqueurs
• Author: Helena Drmić
• 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: 2012-09-24, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Cilj istraživanja bio je kvantificirati promjene sastava polifenola i antioksidacijskog kapaciteta čokoladnih likera proizvedenih od čokolada različitih udjela kakaovih dijelova (30, 32, 50 i 72 %) u kombinaciji s različitim koncentracijama etanola (20, 25 i 30 %) tijekom tromjesečnog odležavanja. Polifenolni profil uzoraka određen je UV-VIS spektrofotometrijskim metodama, kao i antioksidacijski kapacitet koji je određen primjenom ABTS (2,2-azino-bis(3-etilbenzotiazolin-6-sulfonska kiselina) i DPPH (2,2-di(4-tertoktofenil)-1-pikrilhidrazil) metoda. Reološka svojstva istih određena su rotacionim reometrom Rheometric Scientific RM–180. Povećanjem koncentracije etanola povećava se udio ekstrahiranih polifenola te je najveći udio ukupnih fenola, flavan-3-ola i proantocijanidina određen u likerima proizvedenima od čokolade s 72 % kakaovih dijelova i 30 %-tnim etanolom. Tijekom tromjesečnog odležavanja udio ukupnih fenola, flavonoida i flavan-3-ola se smanjuje, dok se udio proantocijanidina te antioksidacijski kapacitet značajno povećavaju. Uzorci pokazuju svojstva pseudoplastičnih (32, 50, 72 %) i dilatanatnih (30 %) tekućina. Značajan antioksidacijski potencijal čokoladnih likera ukazuje na potrebu daljnjeg razvoja i istraživanja ovih proizvoda u cilju proizvodnje funkcionalnih proizvoda.

Abstract (english)

The main goal of this research was to quantify the changes in the composition of polyphenols and antioxidant capacity of chocolate liqueurs produced of chocolates with different cocoa solids content (30, 32, 50 and 72%) in combination with different concentrations of ethanol (20, 25, 30 %) during three months of storage. The polyphenolic profile of the samples was determined by UV-VIS spectrophotometrical methods, as well as the antioxidant capacity which was evaluated by using ABTS (2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) and DPPH [(2,2-diphenyl-1-picrylhydrazyl) assays. Rheological properties of the above mentioned were determined by Rheometric Scientific RM-180. By increasing the ethanol concentration, the share of extracted polyphenols increases; therefore the highest content of total phenols, flavan-3-ols and proanthocyanidins was determined in chocolate liqueurs produced from chocolate containing 72% of cocoa solids in combination with 30% ethanol. During the first three months of storage the share of total phenols, flavanoids and flavan-3-ols has decreased, while the share of proanthocyanidins and the antioxidant capacity increased significantly. The samples show features of pseudoplastic (32, 50, 72 %) and dilatant (30 %) liquids. The significant antioxidant potential of chocolate liqueurs indicates further development and research in order to produce functional products.

• Keywords: antioksidansi; čokolada; liker; polifenoli; reologija
• Keywords (english): antioxidants; chocolate; liqueur; polyphenols; rheology
• Language: croatian
• URN:NBN: urn:nbn:hr:159:130372
• Study programme: Title: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-10 10:00:14