Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 6Citation - Scopus: 6Evaluation of the Extracts of Purple Basil (<i>ocimum Basilicum</I> L.) as Natural Ph-Indicator Dyes Anticipated To Be Utilised in Intelligent Food Packaging-An Optimisation Study(Wiley, 2024) Erez, Elif; Bayramoğlu, Beste; Bayramoglu, BestePurple basil (Ocimum basilicum L.) extract has significant potential as a natural colorimetric pH-indicator material owing to its abundance in anthocyanins. This contribution is the first to optimise the ultrasound-assisted extraction of purple basil by response surface methodology in terms of maximum total monomeric anthocyanin (TMA) content and pH-dependent increase in green intensity (IGI) using a three-level, three-factor Box-Behnken design. The latter was considered as a measure of the pH-indicator ability of the extracts. The independent variables were ethanol concentration, solvent/solid ratio, and extraction time for two types of solvents [aqueous ethanol with 0.1% (v/v) acetic acid (Ac) or hydrochloric acid]. Optimum conditions were determined for single and combined responses. The extracts were further characterised according to total phenolic content (TPC), percentage polymeric colour (PPC), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) antioxidant, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities. All models explained more than 93% of the variability. The combined response model for the Ac-acidified system gave more favourable optimal conditions [55.25% (v/v) ethanol, 30 mL/g solvent/solid ratio and 39.24 min] regarding lower ethanol consumption and shorter times. Validation experiments verified the model successfully predicted the responses. The corresponding TMA, IGI, PPC, TPC, ABTS, and DPPH values were determined as 4.83 +/- 0.18 mg cyanidin-3-glucoside equivalent, 2.29 +/- 0.05, 68.07 +/- 3.17, 28.79 +/- 1.54 mg gallic acid equivalent, 55.85 +/- 1.71 mg Trolox equivalent, and 16.80 +/- 1.08 mg ascorbic acid equivalent per gram dry weight, respectively.Article Citation - WoS: 23Citation - Scopus: 22Modeling of Polystyrene Under Confinement: Exploring the Limits of Iterative Boltzmann Inversion(American Chemical Society, 2013) Bayramoğlu, Beste; Faller, RolandWe explore the limits of a purely structure based coarse-graining technique, the iterative Boltzmann inversion (IBI), in the coarse-graining of a confined concentrated polystyrene solution. In the first place, some technical considerations and challenges encountered in the course of the optimization process are represented. The concepts of the choice of the initial potentials and the cross-dependency of the interactions as well as the order of optimization are discussed in detail. Furthermore, the transferability of a previously developed CG confined polystyrene solution model, the "parent CG confined model", to different degrees of confinement at constant concentration and temperature is examined. We investigate if a CG force field developed for a confined polymer solution by IBI is sensitive to changes in the degree of localization or arrangement of polymers near the surfaces although the concentration is kept constant. For this purpose, reference atomistic simulations on systems of different confinement levels have been performed. The differences in the structure and dynamics of the chains are addressed. Results are compared with those of an unconfined (bulk) system at the same concentration. The chain dimensions and orientations as a function of the distance from the surfaces are also reported. To the best of our knowledge, this is the first computational study that investigates the structural behavior of polymers in close proximity of the surfaces in a concentrated polymer solution rather than in a melt. Transferability of the parent CG confined model is tested by employing the parent force field in CG simulations of the reference systems. Results indicate that the degree of arrangement of monomers and solvent molecules near the surfaces is an important factor that needs to be paid attention to when considering the application of a CG force field developed by IBI to different degrees of confinement.