Univerzita PardubiceFakulta chemicko- technologická

Univerzita Pardubice

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Publikace detail

Analysis of free and bonded phenolic compounds in malting barley and malt

Autoři: Česlová Lenka | Nožičková Hana | Jirásková Adéla

Rok: 2014

Druh publikace: ostatní - přednáška nebo poster

Strana od-do: nestránkováno

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
eng	Analysis of free and bonded phenolic compounds in malting barley and malt	Phenolic compounds are presented in barley grain as a free or bonded to the cell wall with proteins or carbohydrates. They are enzymatically liberated from this bond mainly during germination in malting process. On the start of the brewing process, only the soluble phenolics are released during mashing. The content of soluble phenolic compounds is therefore very important factor for the quality of beer, because almost 80% of these compounds in beer come from malt. The phenolic compounds can protect the beer before sensory aging because of their antioxidant properties and also exhibit positive influence on health. Soluble phenolic compounds (mainly free non-conjugated and soluble conjugated compounds to the carbohydrates via ester or ether bond) are extracted from barley and malt to the hydro-organic solvents. Insoluble bonded phenolic compounds are necessary to liberate from ether or ester bond by acidic or alkaline hydrolysis, respectively. In this work, the extraction techniques were optimized for isolation of free and bonded phenolic compounds from barley and malt. The amount of phenolic compounds in extracts was determined using reversed-phase high-performance liquid chromatography (RP-HPLC). The best separation was achieved using octadecyl silica gel column packed with fused core particles and gradient elution with methanol and water with 0.3% (v/v) formic acid as a mobile phase. The optimized separation was used for the identification of free and bonded phenolic compounds obtained in natural barley and corresponding malt after laboratory micromalting using HPLC coupled to mass spectrometer. The amount of phenolic compounds was determined in barley differed in variety, location and time of harvesting. Further, the change of phenolic compounds during malting and brewing was investigated.	malt, barley, HPLC/MS, phenolics