3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
P10 MONITORING OF FERuLIC ACID CONTENT
DuRING MALT PRODuCTION
SYLVIE BěLáKOVá, REnATA MIKULíKOVá,
ZDEněK SVOBODA and SIMOnA MACUCHOVá
Research Institute of Brewing and Malting, Malting Institute
Brno, Mostecká 7, 614 00 Brno, Czech Republic,
belakova@brno.beerresearch.cz
Introduction
Antioxidant activity of ferulic acid plays an important
role in a biochemical process of beer production. Currently,
causes of wort haze have been investigated and relationships
between wort haze, filterability and beer quality have been
studied. Information on ferulic acid may help elucidate causes
of haze formation 1 .
Ferulic acid (4-hydroxy-3-methoxycinnamic acid)
belongs to phenolic acids derived from cinnamic acid. It is a
natural antioxidants and inhibitors of enzymatic browning. In
plant cell walls it protects cells from the effect of pathogens,
controls expansibility of cells, growth and affects biological
digestibility. Ferulic acid is frequently a part of fibre where it
is bound by ester linkage to hemicelluloses.
Generally, ferulic acid plays a principal role in breakdown
of barley caryopsis cell walls. High content of ferulic
acid in walls can serve as a protection against premature
hydrolysis. The presence of ferulic acid protects cell walls
against microbial attack. It stops lipid peroxidation and is effective
at suppression of hydroxyl radicals 2,3 .
The aim of our project was to determine the dependence
of ferulic acid content on a barley variety and malting technology.
Experimental
Ferulic acid was determined in samples of eight barley
varieties (Jersey, Maltz, Bojos, Radegast, Sebastian, Prestige,
Tolar, and Xanadu). Barleys were from harvest 2007 and they
came from two different growing localities – Krásné Údolí
(forage area, worse growing conditions for spring malting
barley) and Věrovany (sugar-beet area, good growing condi-
s595
tions for spring malting barley). Malts were prepared in the
micro malting plant of the Malting Institute of the RIBM in
Brno using the method with short steep and sucking off CO 2 .
Wort was made by a so-called congress method, i.e. standard
mashing procedure with finely ground malt.
Alcalic hydrolysis with 2 M of natrium hydroxide was
used to release ferulic acid from compact homogenized samples.
After pH adjustment, the extract was purified using the
SPE (Solid Phase Extraction).
The purified extract was microfiltered and transferred to
a vial. In liquid samples extraction with alcalic hydrolysis
was omitted, following procedure remains the same.
The samples were then analyzed using gradient elution
on the UPLC WATERS ACQUITY liquid chromatograph
equipped with WATERS 2996 PDA detector. Mobile phase
consisted of 0.05M phosphate buffer (pH 3.5) and acetonitrile.
Column used was ACQUITY UPLC BEH C18 1.7 µm
2.1 × 50 mm.
Results
Content of total ferulic acid was determined in a series
barley – malt – wort. Results are presented in the Table I.
Conclusions
The results of measurement prove the dependence of
content of total ferulic acid on a variety and growing locality
in the series barley – malt – wort.
Concentration of total ferulic acid in barley samples
varied in the range of 650–950 mg kg –1 in dependence on a
variety and growing locality.
Concentration of total ferulic acid in malt samples varied
in the range of 900–1,740 mg kg –1 in dependence on a variety
and growing locality.
Concentration of total ferulic acid in wort samples varied
in the range of 6–9 mg dm –3 in dependence on a variety and
growing locality.
Results were obtained in the framework of solution of
projects: VZ MSM 6019369701 and MŠM VC 1M0570
Table I
Content of total ferulic acid in a barley – malt – wort chain from the localities Krásné Údolí and Věrovany
Krásné údolí Věrovany
Barley Malt Wort Barley Malt Wort
[mg kg –1 ] [mg kg –1 ] [mg dm –3 ] [mg kg –1 ] [mg kg –1 ] [mg dm –3 ]
Jersey 746.1 1,012.6 7.99 825.1 1,537.0 8.09
Maltz 693.7 1,044.6 7.42 803.1 1,613.2 8.01
Bojos 672.9 970.5 6.14 682.0 1,392.1 5.52
Radegast 806.7 1,067.0 6.05 844.1 1,361.6 5.91
Sebastian 712.2 948.7 8.87 832.9 1,737.4 6.96
Prestige 733.5 1,113.9 7.90 911.0 1,428.6 7.23
Tolar 734.3 1,153.7 6.11 825.4 1,563.2 5.57
Xanadu 648.8 905.9 6.44 692.4 1,263.0 8.45