3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
P02 DETERMINATION OF β-CAROTENE
IN TOMATO by hIGh PREFORMANCE
LIQuID ChROMATOGRAPhy wITh
ELECTROChEMICAL DETECTOR
PETRA VOJTíŠKOVá a , BAYAnMUnKH
ALTAnGEREL a , DAnIELA KRAMářOVá a , OTAKAR
ROP a and IGnáC HOZA a
a Department of food Engineering, Faculty of Technology,
T.Bata University in Zlin, Czech Republic,
bayanmunkh_mn@yahoo.com
Introduction
Commonly studied carotenoid in the human diet is
β-carotene because of its antioxidative and provitamin A
activities. Provitamin A carotenoids, particularly β-carotene
in fruits and vegetables, are the major source of vitamin A
for its deficiency is a serious health problem in many developing
countries. The abundant sources of β-carotene are
sweet potatoes, carrots, spinach, tomato and other vegetables
and fruits. Since tomatoes are major use for human dietary
in many countries, it is becoming a prevention of deficiency
of antioxidant vitamins. Many studies have been focused on
antioxidant vitamins content in tomatoes. Abdulnabi et al. 1
investigated the antioxidative vitamin (vitamin E, vitamin C
and β-carotene) content in tomatoes cultivated in Hungary,
using HPLC. This study suggests that the highest values of
β-carotene were found in Gitana, Katinka and Delfino cultivars
(3.13–3.79 μg g –1 ) and the lowest levels of β-carotene
were in Tampo and Selma cultivars. Therefore, β-carotene
occurs in tomatoes and various tomato products in amount of
0.23–2.83 mg 100 g –1 (ref. 2 ).
The objective of this work was to estimate, using modern
analytical techniques (ESA Coulochem III Multi-Electrode
Detector), and the β-carotene content of tomatoes.
Experimental
High performance liquid chromatography (HPLC) is
the most commonly used method for the separation, quantitation,
and identification of carotenoids found in vegetables
samples.
S a m p l e P r e p a r a t i o n
Initially a 10 g sample of tomato was placed in a 50 ml
flask and mixed with 26 ml of extraction solvent (acetone
: hexane, 50 : 50, v/v). The mixture was shaken in a water
bath at 35 °C for 20 min. The upper phase was collected and
poured into a 50 ml flask. The lower phase was extracted
again with same solvent and shaken for 30 min. The upper
phase was also collected and poured into the same flask.
After filtration through Filtrak no.390 filter paper. The filtrate
was poured into a 250 ml flask and evaporated under
vacuum at 30 °C and residues were redissolved in 5 ml of
ethanol. The solution was filtrated through a 0.45 μm nylon
filter and 20 μl was injected into HPLC system. HPLC separation
was performed using ESA HPLC with ECD detection
s577
(Coulochem III) which is equipped with analytical column
Supercosil LC18-DB (250 × 4.6mm, particle size 5 μm).
Separation took place at 30 °C, flow rate of mobile phase
(methanol : acetonitrile : phosphoric acid) was 1.0 ml min –1 .
Potentials of the cells for detector were 500 and 600 mV.
β-carotene standard solution concentrations ranging
from 25 to 400 μl ml –1 were prepared for the standard curve.
I d e n t i f i c a t i o n a n d Q u a n t i f i c a t i o n
o f β - c a r o t e n e i n T o m a t o
The identification of β-carotene was carried out by the
retention time. The equation from the calibration curve was
used for the calculation of the amount of β-carotene in tomatoes.
The regression equation and correlation coefficient (R 2 )
were obtained using Microsoft Excel 2003 software to calculate
the quantity of β-carotene in tomatoes.
Results
Typical chromatogram depicting the separation of a βcarotene
standard solution is shown in Fig. 1. We were interested
in checking chromatographic condition and retention
time of β-carotene using a selected method in this investigation.
Fig. 1. Chromatogram of standard β-carotene
The predominant peak at approximately 3.3 min is
β-carotene. This value is used for identification of β-carotene
in samples. The calibration curve was measured with the
Fig. 2. Calibration curve of β-Carotene