title: Adsorption of olive leaf (Olea europaea L.) antioxidants on silk fibroin.
abstract: The adsorption isotherms of oleuropein and rutin were evaluated at different temperatures, pH values, and solid/liquid ratios. The experimental data of adsorption isotherms were well fitted to a Langmuir model. The maximum adsorption capacities were determined as 108 mg of oleuropein/g of silk fibroin and 21 mg of rutin/g of silk fibroin. After adsorption of oleuropein and rutin, the antioxidant capacity of silk fibroin increased from 1.93 to 3.61 mmol of TEAC/g. Silk fibroin also gained antimicrobial activity against Staphylococcus aureus and Klebsiella pneumoniae after adsorption of olive leaf antioxidants. In a desorption process, 81% of rutin and 85% of oleuropein were removed from the adsorbent surface in 70% aqueous ethanol solution. Consequently, silk fibroin was found to be a promising biomaterial for the production of functional food or dietary supplements and for the purification of oleuropein and rutin from olive leaf extracts.
authors.affiliation: Biochemical Engineering Research Laboratory (BERL), Department of Chemical Engineering, Izmir Institute of Technology, Gülbahçe Köyü, 35430 Urla-Izmir, Turkey.
authors.forename: Deniz
authors.initials: D
authors.lastname: Bayçin
authors.forename: Evren
authors.initials: E
authors.lastname: Altiok
authors.forename: Semra
authors.initials: S
authors.lastname: Ulkü
authors.forename: Oguz
authors.initials: O
authors.lastname: Bayraktar
mesh_terms: D000327:Adsorption; D000890:Anti-Infective Agents / Q000494:pharmacology; D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology; D005349:Fibroins / Q000737:chemistry*; D005419:Flavonoids / Q000494:pharmacology; D057888:Iridoid Glucosides; D039823:Iridoids; D031658:Olea / Q000737:chemistry*; D010636:Phenols / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry*; D059808:Polyphenols; D011714:Pyrans / Q000737:chemistry; D012431:Rutin / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000890:Anti-Infective Agents; D000975:Antioxidants; D005419:Flavonoids; D057888:Iridoid Glucosides; D039823:Iridoids; D010636:Phenols; D059808:Polyphenols; D011714:Pyrans; C002769:oleuropein; D012431:Rutin; D005349:Fibroins