Izvorni znanstveni članak
The Polyphenols Stability, Enzyme Activity and Physico-Chemical Parameters During Producing Wild Elderberry Concentrated Juice
Ante Galić
orcid.org/0000-0002-0155-7228
; University of Zagreb, Faculty of Agriculture, Svetošimunska cesta 25, 10000 Zagreb, Croatia
Verica Dragović-Uzelac
; University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia
Branka Levaj
; University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia
Danijela Bursać Kovačević
; University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia
Stjepan Pliestić
; University of Zagreb, Faculty of Agriculture, Svetošimunska cesta 25, 10000 Zagreb, Croatia
Sabina Arnautović
; University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia
Sažetak
The influence of processing wild elderberry into concentrated juice on polyphenols (total phenols, flavonoids, non-flavonoids, anthocyanins, flavan-3-ols, hydrolysed tannins) stability, activity of polyphenol oxidase (PPO) and peroxidase (POD), and changes of physico-chemical parameters (total and soluble dry matter, total acidity, pH, sugars) were investigated. The amounts of total phenols, flavonoids, non-flavonoids, falvan-3-ols and hydrolysed tannins were analyzed using Folin-Ciocalteu colorimetric method, while the total anthocyanins were determined by bisulphite bleaching method. Total phenols ranged from 25.87 mg/g DM to 38.87 mg/g DM. Total anthocyanins were the most abundant polyphenols in all investigated samples (raw elderberries, elderberries after blanching, elderberry juice after disintegration and pressing, concentrated elderberry juice) and their concentration ranged from 13.12 mg/g DM to 25.67 mg/g DM. Other polyphenols determined in high concentration were hydrolysed tannins, followed by fl avan-3-ols, flavonoids and nonfavonoids. After blanching, the concentration of all polyphenols did not decrease significantly. After disintegration of elderberries the concentration of all polyphenols increased, probably due to inactivation of PPO and POD and better isolation of polyphenols from homogenized puree. During processing of elderberry juice into concentrated juice most polyphenols were stable. Total acidity and pH value were not changed during processing, whereas the amounts of total and reducing sugar increased after pressing and additionally after concentration. The obtained results suggest that raw elderberries as well as elderberry concentrated juice are high potential source of polyphenols especially anthocyanins.
Ključne riječi
elderberry; polyphenols; anthocyanins; enzymes; physico-chemical parameters
Hrčak ID:
47371
URI
Datum izdavanja:
14.12.2009.
Posjeta: 1.579 *