Letno poročilo 2005

Laboratorij za prehrambeno kemijo
Laboratory for Food Chemistry
90
intenziteto in ton barve, ve~ vitamina C, poleg
antocianinov, zna~ilnih za jagodni nektar, so
vsebovali {e antocianine ~rnega ribeza. Med
staranjem so se vsebnosti merjenih parametrov
v nektarjih z dodatki koncentratov
bolje ohranile, predvsem Pg3G, zna~ilen za
barvo jagode. Senzori~no so bili takoj in po
staranju bolje ocenjeni nektarji z dodanimi
koncentrati. Sedaj se dogovarjamo {e za
industrijsko uporabo pripravljenih koncentratov.
- V okviru EU projekta TOM so bile na{e
raziskave usmerjene v izolacijo biolo{ko
aktivnih spojin prisotnih v odpadkih iz
proizvodnje izdelkov iz paradi`nika. Ugotovili
smo, da vzorci vsebujejo precej triterpenoidov,
od katerih smo uspeli identificirati
in pribli`no ovrednotiti amirin v CO 2 ekstraktih
ostankov po predelavi paradi`nika. Razvili
smo nov postopek ekstrakcije in izolacije dveh
encimov pektin metilesteraze (PME) in
poligalakturonaze (PG) iz paradi`nika. Izolirali
smo eno od oblik PG in eno od oblik PME, ki
za svoje delovanje ne potrebuje natrijevega
klorida in bi jo lahko uporabili v prehrambeni
industriji. Za izolacijo so bile klju~nega
pomena kratke monolitne kolone (CIM ® diski)
podjetja BIA Separations d.o.o., Ljubljana.
Oba encima (PG in PME), ki smo ju uspeli
izolirati ~ista in z ohranjeno aktivnostjo, je
nizozemsko podjetje Catchmabs uporabilo za
generiranje monoklonskih protiteles iMab in
nato za razvoj metode za direktno izolacijo
teh encimov iz ekstrakta paradi`nika z
afinitetno kromatografijo.
- Raziskovali smo tudi, kak{en vir karotenoida
likopena (rde~ega barvila zrelega paradi`nika)
so razli~ni komercialni izdelki na slovenskem
tr`i{~u (pasirani paradi`nik, ke~api, dvojni
koncentrati, prehranski dodatek likopena v
obliki tablet, itd). Ekstrakcija likopena in
priprava testne raztopine iz razli~nih vzorcev
predstavljata najbolj kriti~no fazo analize.
Lo~bo velikega {tevila geometrijskih izomer
likopena smo izvedli na koloni C30, z
and one form of PG were isolated using short
monolithic columns (CIM ® disks, Bia Separations
d.o.o., Ljubljana, Slovenia). Both enzymes
(pure PME and pure PG with preserved
activity) were used in the year 2005 by the
company Catchmabs (Wageningen) as targets
for the iMab generation, and thereafter
for the development of the method for the
direct isolation of these enzymes from tomato
extract by means of affinity chromatography.
- We investigated also what source of carotenoid
lycopene are different commercial products
on Slovenian market (tomato purees,
ketchups, double concentrates, a dietary supplement
formulated as tablets, etc). Extraction
of lycopene and preparation of the test
solutions was found to be the most critical
phase of the analysis. The separation of a
great number of geometrical isomers of
lycopene was performed on the column C30
using a single component mobile phase,
which is a big advantage of our method compared
to the published methods. So we determined
not only the total content of
lycopene in different samples but also the
content of isomers.
- In the frame of cooperation with the group
from University of Helsinki (Faculty of Pharmacy,
Finland) we finished the work about
the TLC separation of catechins. With the
partners from Palacky University (Faculty of
Medicine, Institute of Medical Chemistry and
Biochemistry, Olomuc, Czech Republic) we
investigated biological and chemical variability
of yacon (Smalanthus sonchifolius). Colleagues
from the Institute for hop and brewing
industry from @alec, Slovenia, prepared
us the first group of samples of roots of plants
from Boraginaceae family containing bioactive
naphtoquinones. Within the collaboration
with researchers from Biotechnical
Faculty (Department of Agronomy, Ljubljana,
Slovenia), we performed some preliminary
experiments with cuticular extracts of cabbage.
Samples were taken from cabbages