3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
P67 ANTIOxIDANT AND ANTIMuTAGENIC
ACTIVITy OF DRIED FRuIT, DRuIT TEAS
AND CEREAL FRuIT PRODuCTS
IVAnA MáROVá a , MICHAELA BAROŠOVá a ,
MARTInA TOMKOVá a , HEDVIKA VOnDRáČKOVá a ,
KATEřInA DUROňOVá a and RADKA KOČí a
a Institute of Food Science and Biotechnology, Brno University
of Technology, Purkyňova 118, 612 00 Brno, Czech
Republic,
marova@fch.vutbr.cz
Introduction
Cereal products form important par of human nutrition.
They contain high amount of saccharides, proteins, fiber,
vitamins, minerals and other nutrients. There are many studies
about benefitial healt effect of cereals in prevention of
cardivascular diseases, cancer and hyperlipidaemia. At this
time cereals are recommended mainly in the form of complex
natural saccharides digested for a long time. Many cereals are
mixed with other components as cocoa, nuts, seeds, hioney,
chocolade, and also dried fruit. Addition of several kinds of
dried fruit could enhance beneficial effect of cereal product.
In this work some biologically active substances in dried
fruit, fruit teas and cereal products were analyzed.
Material and Methods
8 kinds of fruit teas (apple, pear, black currant, lemone,
cherry etc.) were erolled into this study. 14 kinds of dried fruits
were analyzed (apple, pear, plum, berries, tropical kinds
etc). 9 kinds of cereal müsli bars with addition of dried fruit
(e.g. berries, bear, apple, pear, plum, orange etc.) were analyzed
too.
A n t i o x i d a n t A n a l y s i s
Total phenolics were analyzed colometrically with Folin
Ciocalteu reagent (750 nm). Total flavonoid content was analyzed
colometrically with nanO 2 + AlCl 3 (510 nm).Total
antioxidant capacity was measured by Randox kit.
Individual flavonoids were analyzed by RP-HPLC/
UV-VIS method. Using extrenal standards concentration
of ((–)catechin, catechin gallate, chlorogenic acid, epicatechin,
morin, quercetin, rutin was done. Samples (20 μl) were
injected into the RP-18 column (Biospher PSI 200 C18, 7 μm,
150 mm × 4.6 mm). Mobile phases were methanol/water
(55 : 45) for catechins and methanol/acetonitrile/water + 1%
phosporic acid (20 : 30 : 50) for flavonoid analysis. The flow
rate was maintained at 0.75 ml min –1 , analysis was performed
at 30 °C. Carotenoids (beta-carotene, lycopene, luteine) were
analyzed by RP-HPLC with spectrophotometric detection
using Hypersil C18, 5 μm, 250 mm × 4.6 mm column, isocratic
elution by methanol at the flow rate 1.1 ml min –1
and at 45 °C.
Identifiaction of individual flavonoids and catechins was
performed by on-line LC/MS/ESI analysis (Mass spectrometer
LCQ Advantage Max). Optimalization of mass spectro-
s722
metry analysis in negative mode was done using chlorogenic
acid. Samples of beer were mixed with 5 times higher amount
of 2% HCl and extracted by SPE (Amid-2 column). Isocratic
elution was performed by mobile phase acetonitrol:1% acetic
acid 50 : 50 at flow rate 0.4 ml min –1 at 30 °C. Individual
components were detected in full scan module.
Ascorbic acid was determined usin RP-HPLC on Hypersil
APS-2, nH2, 5 μm, 150 mm × 4.6 mm column. Samples
were stabilized by 2% HPO 3 , 20 μl was injected. Mobile
phase was natrium acetate/acetonitrile (95 : 5). Analysis was
performed at flow rate 0.6 ml min –1 and 30 °C. Microtitration
metod with 2,6-dichlorindofenol was used as comparative
mthod too. The end point of titration was determined by pink
colour.
A n t i m u t a g e n i t y A s s a y
Test strain Saccharomyces cerevisiae D7 was used for
antimutagenic effect trstiny. The frequency of spontaneous
convertants at the tryptophan locus (trp5-12/trp5-27) and
revertants at the isoleucine locus (ilv-1-92/ilv1-92) was
tested. In each assay positive and negative controls were
included. For positive controls 4-nitroquinoline-1-oxide was
used as standard mutagen. Experiments were carried out by
1-day treatment of the growing cells with tested samles. After
treatment the cells were washed with with phosphate buffer
and plated on a solid medium. After 5-days cultivation
at 28 °C Ile-revertants and Trp-convertants colonies were
counted. Five consecutive experiments were performed.
S e n s o r y A n a l y s i s
A group of 21 respondents were enrolled into orientation
sensory study. They tested several fruit tea and evaluated
basic sensory parameters. The droup of respondents was divi-
ded into two age-different groups:
•
•
seniors: total 13, age 68.5 ± 7.16; 10 F/3 M,
juniors: total 8, age 27.13 ± 3.63; 6 F/2 M.
Additionally, consumer questionnaire was completed
by 35 student respondents. Preferences and consumption of
dried fruit and cereal bars were evaluated.
Results
Analysis of dried fruits showed high level of vitamins
and phenolics mainly in berries. High level of carotenoids
was observed in dried apricots and plums. High antioxidant
activity was found mainly in dried apples, cranberries and
blueberries (Table I).
The highest content of total phenolics, total flavonoids,
total antioxidant capacity, procyanidin B2 and chlorogenic
acid was measured in plums and blueberry bars (Table II).
The highest level of reduced saccharides was evaluated in
raspberry and cereal bars.
Higher antixidant content was found in herbal teas than
in fruit teas. Comparing bag teas with loose leaf teas higher
antioxidant activity was shown in loose leaf teas. In all tea
samples catechins – catechin, epicatechin, epicatechin gallate