Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Structural Changes in Fasted State Dietary Mixed Micelles Upon Solubilization of Beta-Carotene(2022) Bayramoğlu, BesteIt was aimed to investigate the structural changes taking place in duodenal mixed micelles (MM) at fasted state with the incorporation of fatty acids (FA) and the morphological transformations in these MMs upon solubilization of β-carotene (BCR) through coarse-grained (CG) molecular dynamics (MD) simulations. All simulations were performed with GROMACS 2019 simulation package using the Martini force field. Lauric acid (LA), stearic acid (SA) and linoleic acid (LNA) were used to explore the effects of FA chain length and unsaturation. Micelle swelling was observed with the incorporation of all FAs. The increase in size was in line with increasing FA chain length and unsaturation. MMs incorporating LA and SA were ellipsoidal in shape, while polyunsaturated LNA resulted in a worm-like MM. Upon solubilization of BCRs, swelling was observed only in the MMs with long-chain SA and LNA. No micelle growth was observed in the plain and LA MMs despite their smaller sizes. This was attributed to their low-density hydrophobic cores, which allowed a condensation effect induced by the interactions between BCRs and POPC tails. It is inferred that when the micelle is large enough to solubilize BCRs, whether or not swelling will take place depends on the core density. The increase in micelle size was very small in the MM incorporating LNA compared to that in the MM with SA, which was accompanied by an elliptical-to-cylindrical shape transformation. This was due to the fluid nature of the worm-like LNA micelle, which readily allowed the solubilization of 3 BCRs within its core. By resolving the internal structures of BCR incorporated MMs, this study gives valuable insight into the effects of FA chain length and unsaturation on the solubilization behavior of dietary MMs. The results are expected to give direction to the development of rational design strategies for effective BCR delivery systems.Research Project Yarı mamul taze meyve ve sebzeler için katmanlı depozisyon yöntemi ile yeni nesil ince yenilebilir kaplamaların geliştirilmesi(2016) Bayramoğlu, Beste; Üney, Sinem; Koca, NazanBu çalışmanın amacı kitozan ve sodyum kazeinat kullanılarak katmanlı depozisyon ile çok katmanlı (LbL) yenilebilir kaplamaların elde edilmesidir. pH, adsorpsiyon süresi ve katman sayısının film oluşumuna etkileri incelenmiştir. Film oluşumu UV-Vis spektrofotometre ve yüzey plazmon rezonansı (YPR) ile ‘yerinde’ takip edilmiştir. Sonuçlar, LbL kaplama oluşumunun sadece her iki polielektrolitin de ortalama yük yoğunluğuna sahip olduğu pH birleşiminde (5,5-5,5) gerçekleştiğini göstermiştir.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.