3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
Compounds in food samples are identified in MS spectra
according to m/z values of determined standards (Table I).
Phenolic substances were analysed with higher sensitivity
than carotenoids, because of its moderate polarity – general
condition of electrosprey use 3,5 .
Fig. 3. shows an exemple of chromatogram of several
phenolics contained in orange.
Fig. 3. Phenolics in orange juice: naringanin, catechin, quercetin,
kaempferol, rutin, acid chlorogenic and procyanidin
Table II
Antioxidants in food samples
Sample
Total phenolics β-carotene
[mg 100 g –1 ] [μg 100 g –1 ]
orange 572 ± 13 264.3 ± 1.2
lemon 388 ± 12 218 ± 8
tangerine 148 ± 13 720 ± 25
grapefruit 172 ± 6 714 ± 36
apple 2181 ± 43 593 ± 70
carrot 1352 ± 46 5289 ± 123
tomato 13.4 ± 0.8 14.1 ± 2.1
sweet pepper 4.37 ± 0.03 4660 ± 27
onion 16.3 ± 1.0 40.1 ± 1.9
garlic 1.32 ± 0.04 –
potato 379 ± 16 2077 ± 127
gourd – seeds 1898 ± 28 –
sunflower-seeds 517 ± 10 –
Fruit samples were observed as the best and complex
sources of phenolics (Table II). Amount of total phenolics
was highest in apple, the mostly consummed fruit. But considerable
yield was observed in orange as well as in sunflowerseeds.
Very important food source of phenolics are also carrot
and/or gourd-seeds.
Antioxidant capacity of carrot is increaced by highlevel
of β-carotene (carotenoids). Important concentration of
s683
carotenoids was observed also in sweet pepper and/or potato
(Table II).
Studied samples contained rutin and/or acid chlorogenic
as principal phenolics, their distribution in individual fractions
of food is demonstrated on Fig. 4 and Fig. 5.
General part of phenolic substances is presented in fruit
and/or vegetable juice, while higher amount of selected phenolics
was observed in pulp.
Fig. 4. Occurrence of rutin and acid chlorogenic in juice
Fig. 5. Presence of rutin and acid chlorogenic in pulp
Peel was analysed in apple and potato only (data not
show). This fraction was characteristic by higher amount of
chlorogenic acid, while other analysed phenolics were presented
in very lower concentration and/or was not determined.
Conclusions
Combined instrumental technique LC/ESI-MS is more
suitable for analysis of phenolics than in identification of
carotenoids. Carotenoid are lipid-soluble pigments, so ionisation
process with ESI source is insufficient. More important
method for carotnoid analysis is LC/APCI-MS.
Analysis of compound distribution is surely influenced