Page 196 - PowerPoint Presentation

PROMENA BOJE ANTOCIJANA U ZAVISNOSTI OD PH VREDNOSTI

CHANGE COLOUR OF ANTHOCYANINS DEPENDING ON PH VALUE

Autor: NATALIJA ŽIVADINOVIĆ učenica osmog razreda škole „Josif Pančid“ Regionalni centar za talente
Beograd II Mentor: GORANA JENDRIŠEK student Biološkog fakulteta

REZIME

Antocijani su biljni pigmenti koji strukturno pripadaju polifenolima odnosno flavonoidima. Zajedničke karakteristike
svih antocijana su dva benzenova prstena povezana sa tročlanim ugljenikovim nizom. Svako od ovih jedinjenja
sadrži hidroksilne grupe, čiji broj i položaj određuju hemijska svojstva i pH vrednost te supstance. S obzirom da
antocijani menjaju boju u zavisnosti od pH vrednosti, mogu se koristiti kao indikatori.
Antocijani se u prirodi ne mogu nadi u slobodnom stanju zbog velike reaktivnosti. U biljkama se nalaze u vidu
heterozida. U ovom radu,kao izvor antocijana korišden je crveni kupus. Njegovim rastvaranjem u vodi, dobijen
rastvor ljubičasto-plave boje koji je korišden kao indikator.

Cilj ovog rada bilo je ispitivanje promene boje antocijana u rastvorima supstanci različitih pH vrednosti i njihovo
upoređivanje sa supstancama nepoznate pH vrednosti.

Eksperimentom je utvrđeno da dolazi do promene boje dodavanjemrastvora crvenog kupusa u rastvore različitih
supstanci, a promena boje zavisi od pH vrednosti. Supstance koje imaju nizak pH su crvene boje, one čiji je pH u
opsegu od 6 do 10 plave, a rastvori vedeg pH su žute i zelene boje. Do promene boje dolazi zbog promene u
hemijskoj strukturi.

Ključne reči:antocijani, flavonoidi, pH vrednost, crveni kupus.

SUMMARY

Anthocyanins are plant pigments which structurally belong to polyphenols respectively flavonoids. Common
features of all anthocyanins are two benzene rings connected by a three-member carbon series. Each one of these
compounds contains hydroxyl group, whose number and position determine chemical properties and the pH value
of these substances.Considering that anthocyanins change colour depending on pH, they can be used as indicators.

Anthocyanins are naturally not found in the free state because of their high reactivity. They are found in plants in
the form of heterosides. In this study,red cabbage was used as a source of anthocyanins. As a result of its
dissolution in water, resulting solution becomes violet-blue colour and that solution was used as an indicator.

The objective of this study was to determine change in colour of anthocyanins in solutions substances of different
pH values and their comparison with substances of unknown pH values.

The experiment showed that there is a change of colour pouring solution of red cabbage in a solution of different
substances, and change of colour depending on the pH value. Substances which have a low pH had red colour,
those which have a pH between 6 and10 were blue and all solutions higher pH the yellow and green colour. There
were change of colours because there is a change in the chemical structure. Key words:anthocyanins, flavonoids,
pH value, red cabbage.