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

Autor: Marko Karoglan, Ivana Tomaz, Marina Anić, Nera Huzanić, Iva Šikuten, Edi Maletić, Darko Preiner, Petra Štambuk, Jasminka Karoglan Kontić
Rok vydání: 2021
Předmět:
Zdroj: Journal of Central European Agriculture
Volume 22
Issue 2
Journal of Central European Agriculture, Vol 22, Iss 2, Pp 429-442 (2021)
ISSN: 1332-9049
DOI: 10.5513/jcea01/22.2.3135
Popis: 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 freezedried 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.
Cilj ovog rada bio je utvrditi učinak različitih postupaka sušenja: liofilizacije, sušenja u sobi i sušenja u pećnici na fenolni sastav grožđa sorata 'Regent' i 'Cabernet Sauvignon'. Nakon sušenja uzorci su usitnjeni, podvrgnuti ultrazvukom potpomognutoj ekstrakciji te potom analizirani primjenom tekućinske kromatografije visoke djelotvornosti. Ovo je istraživanje jasno pokazalo da uporaba različitih metoda sušenja značajno utječe na sadržaj polifenola u ekstraktima kožice grožđa. Najveći sadržaj antocijan-diglukozida sačuvan je liofilizacijom, 15706.86 mg/kg u slučaju 'Regenta', dok je sadržaj antocijan-monoglukozida najbolje očuvan sušenjem pri sobnoj temperaturi, 216778.68 i 9220.30 mg/kg u slučaju 'Regenta' odnosno 'Cabernet Sauvignona'. Najveći sadržaj flavonol-glikozida (2583.04 i 1429.64 mg/kg u slučaju 'Regenta' odnosno 'Cabernet Sauvignona'), hidroksicimetnih kiselina (1303.31 i 544.88 mg/kg u slučaju 'Regenta' odnosno 'Cabernet Sauvignona') i stilbena (2321.52 i 79.36 mg/kg u slučaju 'Regenta' odnosno 'Cabernet Sauvignona') zabilježen je u uzorcima sušenim u pećnici. Primjenom liofilizacije očuvan je najoptimalniji sadržaj flavan-3-ola. Sadržaj polifenolskih spojeva u uzorcima sušenim u pećnici, nakon razdoblja od 6 mjeseci skladištenja, bio je gotovo identičan sadržaju u uzorcima analiziranim neposredno nakon sušenja. Najveća razgradnja zabilježena je u uzorcima sušenim u sobi, dok je u liofiliziranim uzorcima bila umjerena. Rezultati ovog eksperimenta pokazuju da je uzorke potrebno sušiti na različite načine kako bi se dobio najveći sadržaj određenih skupina fenolnih spojeva. Primjena metode sušenja određena je konačnim ciljem osušenog proizvoda s obzirom na sadržaj i sastav različitih polifenolskih spojeva; stoga bi dobiveni rezultati mogli imati primjenu u znanstvenim istraživanjima, ali i u komercijalne svrhe.
Databáze: OpenAIRE