Naslov
Application of Citrus and Apple Fibers for Formulation of Quercetin/Fiber Aggregates: Impact of Quercetin Concentration

Autori
Buljeta, Ivana ; Ćorković, Ina ; Pichler, Anita ; Šimunović, Josip ; Kopjar, Mirela

Izvornik
Plants (2223-7747) 11 (2022), 24; 3582, 11

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
quercetin ; apple fiber ; citrus fiber ; HPLC ; structural changes ; thermal stability ; antioxidant activity

Sažetak
Among flavonoids, quercetin has gained special attention due to its positive biological activi- ties. Quercetin’s disadvantages, such as its hydrophobic nature, poor solubility, and permeabil-ity, could be overcome by complexation with different polymers. Dietary fibers are known as carriers of polyphenols, which can protect them from environmental conditions and thus allow them to be absorbed. In this study, apple and citrus fibers (as applicable food by-products) were used as carriers of quercetin. A constant amount of fibers (1%) and different concentrations of quercetin solution (5 mM, 10 mM, and 20 mM) were complexed. Obtained fiber aggregates were subjected to HPLC to determine the quercetin concentration and antioxidant activity of aggre- gates (ABTS, DPPH, FRAP, and CUPRAC assays). IR spectra were recorded to confirm complexa-tion of quercetin with selected fibers, and an additional DSC study was performed to evaluate the thermal stability of fiber aggregates. The results of HPLC analysis showed that quercetin had higher affinity towards apple fiber than citrus fiber, without proportional trends of adsorption. Consequently, apple fiber aggregates had higher antioxidant potential than citrus fiber aggre-gates. FTIR-ATR analysis showed the formation of new bands and the loss of existing bands when quercetin was present. Adsorption of quercetin also had an impact on the thermal stability of formulated fiber aggregates. For apple fiber, this impact was negative, while for citrus fiber, the impact was positive. These results could contribute to greater understanding of quercetin’s behavior during the preparation of food additives based on polyphenols and fibers.

Izvorni jezik
Engleski

Znanstvena područja
Prehrambena tehnologija

POVEZANOST RADA