Antioxidant activity of model systems pectin/sugars/phenols

U radu je ispitivana antioksidativna aktivnost modelnih sustava pektin i fenolnih tvari, te šećera, pektin i fenolnih tvari. Cilj rad bio je odrediti utjecaj dodatka šećera, saharoze i trehaloze na antioksidativnu aktivnost modelnih sustava u odnosu na modelne sustave bez dodatka šećera te odrediti sinergistički/antagonistički utjecaj pektina i šećera na antioksidativnu aktivnost modelnih sustava s dodatkom obje fenolne tvari. Antioksidativna aktivnost određena je DPPH, ABTS i FRAP metodom. Primjenom DPPH metode utvrđeno je da je modelni sustav pektin, katehin i kvarcetin imao najveću antioksidativnu aktivnost a modelni sustav pektin i kvarcetin najmanju. Dodatkom šećera došlo je do smanjenja antioksidativne aktivnosti. U sva tri modela dodatkom obje fenolne tvari utvrđen je antagonistički učinak. ABTS i FRAP metodom utvrđene su znatno niže vrijednosti antioksidativne aktivnosti svih modelnih sustava. U modelnim sustavima s dodatkom obje fenolne tvari i šećera utvrđen je sinergistički utjecaj na antioksidativnu aktivnost. FRAP metodom utvrđena je najveća antioksidativna aktivnost s dodatkom trehaloze a najveći sinergistički učinak utvrđen je u modelnom sustavu bez šećera.This study examined the antioxidant activity of model systems pectin and phenolic substances, and sugars, pectin and phenolic substances. The aim of this work was to determine addition of sugars, sucrose and trehalose on antioxidant activity in model systems compared to model systems without added sugar and to examine the synergistic/antagonistic effect of pectin and sugar on the antioxidant activity of model systems with the addition of both phenolic substances. The antioxidant activity was determined by DPPH, ABTS and FRAP method. Using DPPH method was established that the model system pectin, catechin and quercetin had the highest antioxidant activity and the model system pectin and quercetin had the lowest antioxidant activity. Added sugar decreased antioxidant activity. In all three models, the addition of both phenolic compounds established antagonistic effect. Significantly lower levels of antioxidant activity, in all model systems, were showen by ABTS and FRAP methods. Model systems, with the addition of both sugar and phenolic compounds, demonstrated synergistic effect on antioxidant activity. The highest antioxidant activity with the addition of trehalose and the greatest synergistic effect was found in a model system without sugar by FRAP method