| Sažetak | Čaj se smatra jednim od najčešće konzumiranih bezalkoholnih pića na svijetu, stoga je nužno
poznavati njegovog sastav i djelovanje na organizam čovjeka. Za pozitivne učinke čaja većim
dijelom su zaslužni organski spojevi poput katehina koji djeluju kao antioksidansi te su time
i više istraženi od samog anorganskog sastava čaja, ali minerali prisutni u čaju također mogu
biti od iznimne važnosti. Neki od njih, poput kalija, kalcija, mangana, željeza, nikla, bakra i
cinka su esencijalni elementi, bez čijeg bi unosa normalna funkcija organizma bila narušena.
Cilj ovog istraživanja bio je odrediti utjecaj određenih parametara pripreme čajnih infuza i
parametara same TXRF analize za multielementnu analizu infuza crne i zelene čajne
mješavine komercijalno dostupne na hrvatskom tržištu. Ispitan je utjecaj duljine pripreme
infuza čajne mješavine (2, 5, 10, 30 i 60 minuta) i duljine mjerenja (600, 1000 i 2000 s) na
sadržaj elemenata od interesa za ljudsko zdravlje. Za većinu elemenata, niti duljina pripreme
infuza niti duljina mjerenja nisu imale statistički značajan učinak na njihov sadržaj. Odabrani
parametri (2 min i 600 s) su primijenjeni za elementarnu analizu svih prikupljenih uzoraka. U
svim ispitivanim uzorcima detektirani su i određen je sadržaj kalija, kalcija, mangana, željeza,
bakra, cinka, broma, rubidija i stroncija dok je nikal detektiran i određen u šest od devet
uzoraka. U najvećim količinama prisutni su kalij, kalcij pa zatim mangan, izuzev uzoraka koji
imaju dodatak cinka, dok su u najmanjim količinama prisutni nikal i bakar. Koncentracija
mangana u svim uzorcima znatno je veća u odnosu na sadržaj ostalih elemenata u tragovima.
Sadržaj cinka značajan je samo u uzorcima s njegovim dodatkom. Kalij, kalcij, željezo, bakar,
brom, rubidij, stroncij i ekstrahirani su u količini koja nije dovoljna da bi infuzi čajnih
mješavina mogli poslužiti kao dobar izvor tih elemenata. |
| Sažetak (engleski) | Tea is one of the most consumed non-alcoholic beverages in the world, therefore it is necessary
to know its composition and effect on the human body. The positive effects of tea are largely
due to organic compounds such as catechins, which act as antioxidants and are therefore more
researched than the inorganic composition of tea itself, but the minerals present in tea can also
be extremely important. Some of them, such as potassium, calcium, manganese, iron, nickel,
copper and zinc are essential elements, without which the normal function of the organism
would be impaired.The aim of this study was to determine the effect of certain parameters of
the preparation of tea infusions and the parameters of the TXRF analysis itself for the
multielemental analysis of black and green tea infusions commercially available on the Croatian
market.It was examined how the length of preparation of the tea infusion (2, 5, 10, 30 and 60
minutes) and the length of measurement (600, 1000 and 2000 s) affects the content of elements
which are important for human health. For the majority of minerals, neither the length of
infusion preparation nor the length of measurement had a statistically significant effect on their
content. The selected parameters (2 min and 600 s) were applied for elemental analysis of all
collected samples.Potassium, calcium, manganese, iron, copper, zinc, bromine, rubidium and
strontium were present in all samples. Nickel was present in six of the nine samples. Potassium
and calcium followed by manganese were present in the largest quantities in all samples, with
the exception of two sample which had artificially added zinc. Nickel and copper were present
in the smallest quantities. The concentration of manganese, in all samples, was significantly
higher than the content of other trace elements. The zinc content was significant only in the
samples with its addition. Potassium, calcium, iron, copper, bromine, rubidium, strontium and
nickel were present in an amount that is not sufficient for tea infusions to serve as a good source
of these elements. |
