Naslov
Effect of different drying methods on the content of polyphenolic compounds of red grape skins

Autori
Tomaz, Ivana ; Štambuk, Petra ; Anić, Marina ; Šikuten, Iva ; Huzanić, Nera ; Karoglan, Marko ; Maletić, Edi ; Karoglan Kontić, Jasminka ; Preiner, Darko

Izvornik
Journal of Central European agriculture (1332-9049) 22 (2021), 2; 429-442

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

Ključne riječi
phenolic-compounds ; biochemical-properties ; antioxidant capacity ; bioactive compounds ; beta-glucosidase ; anthocyanins ; temperature ; stability ; purification ; extraction

Sažetak
The aim of this work was to determine the effect of different drying treatments: freeze-drying, room-drying, and oven-drying on the grape phenolic composition of the 'Regent' and 'Cabernet Sauvignon' varieties. After drying, the samples were grounded, submerged to ultrasound-assisted extraction, and analyzed with high-performance liquid chromatography (HPLC). This study demonstrated that the use of different drying methods significantly affects the content of polyphenols in grape skins extracts. The greatest content of anthocyanins-diglucoside was preserved using freeze-drying, i.e. 15706.86 mg/kg for 'Regent', while the content of anthocyanins- monoglucoside was best preserved by room-drying, i.e. 216778.68 and 9220.30 mg/kg for 'Regent' and 'Cabernet Sauvignon', respectively. The highest content of flavonol glycosides (2583.04 and 1429.64 mg/kg for 'Regent' and 'Cabernet Sauvignon', respectively), hydroxycinnamic acids (1303.31 and 544.88 mg/kg for 'Regent' and 'Cabernet Sauvignon', respectively), and stilbene (2321.52 and 79.36 mg/kg for 'Regent' and 'Cabernet Sauvignon', respectively) was observed in the oven-dried samples. By applying freeze- drying the most optimal content of flavan-3-ol was preserved. Contents of polyphenolic compounds in oven-dried samples after 6 months of storage were almost identical to those in the samples analyzed immediately after drying. The greatest rate of degradation was observed in the room-dried samples while it was moderate in the freeze-dried ones. The results of this experiment demonstrate that it is necessary to dry samples in different ways to obtain the highest content of a certain polyphenolic group of compounds. The application of a drying method is determined by the goal of the final dried product in terms of content and composition of different polyphenolic compounds ; thus, the obtained results could have an application in scientific research and for commercial purposes as well.

Izvorni jezik
Engleski

Znanstvena područja
Poljoprivreda (agronomija)

POVEZANOST RADA