Unit:
Κατεύθυνση Βιομηχανική ΧημείαLibrary of the School of Science
Supervisors info:
Λιούνη Μαρία, Αναπληρώτρια Καθηγήτρια, Τμήμα Χημείας, ΕΚΠΑ
Original Title:
Παρουσίαση της εξέλιξης της αντιοξειδωτικής ικανότητας και του πολυφαινολικού περιεχομένου κατά τα στάδια της ζυθοποίησης
Translated title:
Presentation of the evolution of antioxidant activity and polyphenol content during the stages of brewing
Summary:
The aim of this study was to determine the evolution of the antioxidant activity, total polyphenol content and color of nine beer samples during the production process. Samples were taken at the end of pulping, before boiling, after boiling - while wort was still warm and after the cooling of wort - before the inception of fermentation. Further samples were taken at the end of fermentation. Αn additional sample was taken for beers from breweries, the finished bottled product.
For the determination of the antioxidant capacity of samples two spectrophotometric methods were chosen, the FRAP assay (Ferric Reducing Antioxidant Power), which is based on measurement of the power reduction of ferric ions and ABTS assay, a method of scavenging radical based on electron transfer. Even Folin-Ciocalteu assay, another spectrophotometric method was used to measure indirectly the antioxidant capacity through determination of the total polyphenolic content. Total polyphenols were also studied using European Brewery Convention (EBC) method. Furthermore, color was estimated spectrophotometrically in EBC units. During the various stages of brewing, density was calculated, to track the evolution of the product.
The results of this study generated important information for the development of antioxidant capacity and performance of total polyphenol content and color development between the various stages of brewing. Finally there is a discussion of correlation between these methods and the ability to fully describe the composition of a sample measured.
Main subject category:
Science
Keywords:
Antioxidant activity, Total polyphenols, Color, Beer, Spectrophotometric assays
Number of references:
105
File:
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Dissertation Athanasiou.pdf
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File access is restricted only to the intranet of UoA.
