Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Author: search.filters.author.Buyukkileci, Ali OguzDepartment: search.filters.department.Izmir Institute of Technology

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  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Development of Xylan-Coated Acid-Resistant Micellar Drug Carriers for Colon-Targeted Oral Delivery
    (Taylor & Francis As, 2024) Zeybek, Nuket; Büyükkileci, Ali Oğuz; Polat, Hurriyet; Polat, Hürriyet; Gulec, Sukru; Güleç, Şükrü; Buyukkileci, Ali Oguz; 03.08. Department of Food Engineering; 04.01. Department of Chemistry; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
    Oral delivery of hydrophobic drugs from the stomach through the colon has some requirements: (1) an acid-resistant carrier (2) a colon-specific drug release mechanism; and (3) an enhanced bioavailability. In this study, curcumin-loaded polymeric micelles with a xylan-based composite coating were designed and developed. For this purpose, a new synthesis method was used to precipitate xylan by concurrent chitosan polymerization at different xylan/chitosan ratios using a negatively charged crosslinking agent, TPP. The study was to provide the stability of the coated micellar structures in the stomach (low pH conditions) and their degradation in the colon (a natural environment of bacteria) to release the drug. It was observed that the coating successfully prevented early drug release up to 85%, depending on the fraction of xylan in the coating. The nanocarriers that first passed through the stomach conditions were incubated with a xylanolytic colonic bacterium (Bacteroides ovatus) to determine the bacterium-related release mechanism, which was around 27%. This shows the colon-specific release expectation of coated nanocarriers in the colon environment, with an additional benefit due to the degradation of xylan and an improvement in the colon environment by prebiotic activity.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 5
    The Potential of Walnut Shells for Production of Oligosaccharides by Liquid Hot Water Treatment
    (Springer Heidelberg, 2023) Surek, Ece; Büyükkileci, Ali Oğuz; Buyukkileci, Ali Oguz; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Walnut shell (WS), which is discarded in a large amount, is usually utilized for heating purposes; therefore, obtaining fuctional products can add value to this waste biomass. In this study, xylan was determined as the dominant carbohydrate (18.6% of dry weight) in WS. The potential applicability of liquid hot water (LHW) treatment to WS was investigated in order to solubilize hemicellulose and hydrolyze it into oligomers such as xylooligosaccharide (XOS) as a prebiotic oligosaccharide and recover solid and liquid fractions, which can be raw materials for other value-added products. LHW was applied at different temperatures (170-210 degrees C) for various times (15-120 min), and their effect was combined calculating severity factor (log R-o = 3.39-4.74). The solubilization of biomass was increased (up to 60.9%) with severity. Under optimum conditions (log R-o of 3.95, 190 degrees C-15 min), 81.5% of xylan was hydrolyzed and recovered as mainly XOS (69.8% of xylan), and also xylose and arabinose. The total oligosaccharide (XOS, arabino, gluco- and galacto-oligosaccharides) and monosaccharide (mainly xylose) concentration were 14.3 and 2 g/L, respectively, and by-products did not exceed 1.6 g/L. Moreover, 2.5 mg GAE/mL of total phenolics were obtained at those conditions, whereas that was raised to 3.4 mg GAE/mL at harsher conditions. This study presented that LHW treatment was an eco-friendly alternative method for valorization of WS through production of a liquid with high value-added compounds such as oligosaccharides and solid rich in cellulose and lignin.