44 research outputs found
Measurable entanglement
Amount of entanglement carried by a quantum bipartite state is usually
evaluated in terms of concurrence (see Ref. 1). We give a physical
interpretation of concurrence that reveals a way of its direct measurement and
discuss possible generalizations.Comment: 3 pages, submitted to Applied Physics Letter
Quantification of entanglement via uncertainties
We show that entanglement of pure multi-party states can be quantified by
means of quantum uncertainties of certain basic observables through the use of
measure that has been initially proposed in [10] for bipartite systems.Comment: Changed content, references added 7 pages, no figures, PRA in pres
Entanglement : quantification via uncertainties and search among ultracold bosons in optical lattices
Ankara : The Department of Physics and the Institute of Engineering and Science of Bilkent University, 2009.Thesis (Ph. D.) -- Bilkent University, 2009.Includes bibliographical references leaves 63-69.In the first part of the Thesis, the known measures of entanglement for finite dimensional
systems are reviewed. Both the simplest case of pure states that belong to bipartite systems
and more general case of mixed states are discussed. The multipartite extensions are also
mentioned. In addition to the already existing ones, we propose a new measure of entanglement
for pure states of bipartite systems. It is based on the dynamical symmetry group
approach to quantum systems. The new measure is given in terms of the total uncertainty
of basic observables for the corresponding state. Unlike conventional measures concurrence
and 3-tangle, which measure the amount of entanglement of different groups of correlated
parties, our measure gives the total amount of multipartite entanglement in a specific state.
In the second part of the Thesis, the trapping of bosonic atoms in optical lattices is reviewed.
The band structure together with Bloch functions and Wannier basis are discussed
for this system. In relation with that, the corresponding Bose-Hubbard model and by the use
of this model, the resulting superfluid to Mott-insulator quantum phase transition is summarized.
In this regard, the Bose-Hubbard Hamiltonian of a specific system, namely ultracold
spin-1 atoms with coupled ground states in an optical lattice is considered. For this system
we examine particle entanglement, that is characterized by pseudo-spin squeezing both for
the superfluid and Mott-insulator phases in the case of ferromagnetic and antiferromagnetic
interactions. The role of a small but nonzero angle between the polarization vectors of counterpropagating
lasers forming the optical lattice on quantum correlations is investigated as
well.Öztop, BarışPh.D
Stability of acidified milk drinks: Comparison of high hydrostatic pressure (HHP) and thermal treatments
There is a search for effective stabiliser activity and alternative pasteurisation techniques for acidified milk drinks (AMD). In the present study, AMD were prepared at three different pH (4.0, 4.5 and 5.0) and high methoxyl pectin (HMP) levels (0.2, 0.5 and 0.8%) by thermal (75 °C, 15 min) and high hydrostatic pressure (HHP) (100, 300 and 500 MPa, 5 min) treatments. To achieve minimum steric stability, 0.5% HMP was required. HMP at 0.5%, pH 4.0 and 4.5, produced high protein solubility (60–70%), low storage sedimentation (10–15%) and mean particle size values in the range of 1.70–3.00 μm for all samples. Heat treatment induced lower particle size variation than HHP treatment. Heat-treated samples also showed lower Turbiscan stability index (TSI) values and smaller delta backscattering (ΔBS) variations. Nonetheless, HHP could replace heat treatment at 0.5% HMP concentration and pH 4.0–4.5. © 2022 Elsevier Lt
Investigation of the effects of high hydrostatic pressure on the functional properties of pea protein isolate
This study investigates the effects of high hydrostatic pressure (HHP) on some functional properties of pea protein isolate (PPI). HHP was combined with various temperature and pH conditions to investigate the combined effects of HHP-based food processing conditions on the functional properties of PPI. Herein, PPI solutions prepared at different pH conditions (3.0, 5.0, and 7.0) were subjected to 300, 400, and 500 MPa HHP treatment at 25 and 50°C for 5 min. Water-holding capacity (WHC), solubility, and emulsification activity of PPI samples were determined. Additionally, nuclear magnetic resonance (NMR) relaxometry and Fourier transform infrared spectroscopy experiments were performed for further analysis. Maximum WHC (p < 0.05) was observed for the samples treated at 500 MPa-pH 5.0-50°C whereas maximum solubility (p < 0.05) belonged to the samples subjected to 300 MPa-pH 7.0-50°C treatment conditions. Better emulsification activity was achieved at pH 3.0 regardless of the pressure level applied. The novelty of this study is that NMR relaxometry was introduced as a fast/nondestructive technique to investigate the changes in the functional properties of PPI samples and one of the functional parameters was correlated with NMR relaxation data. Herewith, the longest transverse relaxation time (T2) (p < 0.05) belonged to the samples with maximum WHC. The results showed that HHP is able to modify the functional properties of PPI at specific temperature-pH combinations, and NMR relaxometry technique has a high potential for such studies. Practical Applications: High hydrostatic pressure (HHP) is an emerging technology which is used for its diverse range of applications in food science and technology. Modification of physicochemical and functional properties of food ingredients is one of the latest applications of HHP treatment. This study demonstrated that HHP treatment was able to modify some functional properties of pea protein isolate (PPI) samples such as water-holding capacity (WHC), solubility, and emulsification activity. In addition to pressure level, pH and temperature were also effective on modifying the functional properties of PPI samples. For instance, a high pressure (500 MPa) was required to improve WHC whereas lower pressures (300 MPa) improved the solubility of the samples at high pH and temperature. The results of this study could be used in model HHP studies to improve some functional properties of PPI for different purposes. © 2022 Wiley Periodicals LLC
Challenges in dried whey powder production: Quality problems
Whey is a high nutritional value by-product of the dairy industry. It is generally produced in large quantities and its disposal as wastewater poses environmental risks. For this reason, whey streams are used for the production of value-added products such as dried whey powders. However, there are several challenges related to whey processing that lead to low powder yield and quality, especially caking. These challenges can be addressed by optimization of product formulation and processing parameters. In this review, we discuss the effects of dried whey protein powder production stages and process parameters on the quality of the final powder product. The initial composition of whey used for dried whey powder production affects the final quality of the product. Generally, a high mineral and/or lactic acid content is not desirable since these constituents cause lactose-containing whey particles to adhere to the drying equipment surfaces, thereby reducing the powder yield. An effective lactose pre-crystallization is essential since high amorphous lactose content increases the stickiness of the dried-whey powder particles and induces caking during storage. Therefore, whey should undergo filtration and lactose pre-crystallization before spray drying. Studies show that it is possible to retard caking and improve the quality attributes of dried whey powders by optimizing the product formulation and processing operations. © 2022 Elsevier Lt
Non-Conventional Time Domain (TD)-NMR Approaches for Food Quality: Case of Gelatin-Based Candies as a Model Food
The TD-NMR technique mostly involves the use of T-1 (spin-lattice) and T-2 (spin-spin) relaxation times to explain the changes occurring in food systems. However, these relaxation times are affected by many factors and might not always be the best indicators to work with in food-related TD-NMR studies. In this study, the non-conventional TD-NMR approaches of Solid Echo (SE)/Magic Sandwich Echo (MSE) and Spin Diffusion in food systems were used for the first time. Soft confectionary gelatin gels were formulated and conventional (T-1) and non-conventional (SE, MSE and Spin Diffusion) TD-NMR experiments were performed. Corn syrups with different glucose/fructose compositions were used to prepare the soft candies. Hardness, degrees Brix (degrees Bx), and water activity (a(w)) measurements were also conducted complementary to NMR experiments. Relaxation times changed (p < 0.05) with respect to syrup type with no obvious trend. SE/MSE experiments were performed to calculate the crystallinity of the samples. Samples prepared with fructose had the lowest crystallinity values (p < 0.05). Spin Diffusion experiments were performed by using Goldman-Shen pulse sequence and the interface thickness (d) was calculated. Interface thickness values showed a wide range of variation (p < 0.05). Results showed that non-conventional NMR approaches had high potential to be utilized in food systems for quality control purposes
Non-Conventional Time Domain (TD)-NMR Approaches for Food Quality: Case of Gelatin-Based Candies as a Model Food
The TD-NMR technique mostly involves the use of T-1 (spin-lattice) and T-2 (spin-spin) relaxation times to explain the changes occurring in food systems. However, these relaxation times are affected by many factors and might not always be the best indicators to work with in food-related TD-NMR studies. In this study, the non-conventional TD-NMR approaches of Solid Echo (SE)/Magic Sandwich Echo (MSE) and Spin Diffusion in food systems were used for the first time. Soft confectionary gelatin gels were formulated and conventional (T-1) and non-conventional (SE, MSE and Spin Diffusion) TD-NMR experiments were performed. Corn syrups with different glucose/fructose compositions were used to prepare the soft candies. Hardness, degrees Brix (degrees Bx), and water activity (a(w)) measurements were also conducted complementary to NMR experiments. Relaxation times changed (p < 0.05) with respect to syrup type with no obvious trend. SE/MSE experiments were performed to calculate the crystallinity of the samples. Samples prepared with fructose had the lowest crystallinity values (p < 0.05). Spin Diffusion experiments were performed by using Goldman-Shen pulse sequence and the interface thickness (d) was calculated. Interface thickness values showed a wide range of variation (p < 0.05). Results showed that non-conventional NMR approaches had high potential to be utilized in food systems for quality control purposes
Nuclear Magnetic Resonance (NMR) study of Palm Kernel Stearin: Effects of cooling rate on crystallization behaviour
In this study, effects of different cooling rates (0.5,3.3,4.7 and 6.9 degrees C/min) on the crystallization behavior of palm-kernel-stearin (PKS) were studied by low-field NMR relaxometry. According to results, solid fat content (SFC), longitudinal relaxation time (T1), second moment (M2) and degree of crystallinity (%) of the samples increased with increase in cooling rate from 0.5 to 6.9 degrees C/min. In contrast, transverse relaxation time (T2) demonstrated an opposite behavior with respect to T1 and decreased when the cooling rate increased. Additionally, effects of cooling rate on the changes of polymorph structures were detected by X-ray measurements. Degree of crystallinity showed high Pearson correlation values (alpha <= 0.05) with SFC (r = 0.771) and T1(r = 0.932). Changes in the crystal polymorphs could also be explained by NMR parameters to some extent as can be observed by the strong correlation between the 13 crystal content and T2 (r = 0.927). At the highest cooling rate, 13 ' crystals were the dominant polymorphic form and constituted 75(%) of the total crystals present. Results of this study suggested that NMR relaxometry could be used as a complementary tool to interpret the crystallization behavior of PKS
Manyetik Rezonans Görüntüleme (MRG) ve NMR Relaksometre Teknikleri Kullanılarak Karakterize Edilen Lipozom Sistemleri ile Yag Oksidasyonunu Önleyici Sprey Ürün Geliştirilmesi
TÜBİTAK TOVAG15.02.2017Lipozomlar hem hidrofobik hem de hidrofilik bileşiklerin kapsüle edilmesi amaçlı farmasötik, kişisel bakım, kimya ve gıda endüstrisinde kullanılan, polar yapılar içeren iki tabakalı küresel yağ kesecikleridir. Bu yapılardan oluşan enkapsülasyon sistemlerinin biyo-uyumlu, biyobozunur olmaları, toksik etkilerinin olmaması ve istenildiğinde kapsüllenmiş maddeyi salabilmesi özellikleri bu sistemleri birçok yönden avantajlı kılmaktadır. Ayrıca, polimer bazlı enkapsülasyon sistemleri ile karşılaştırıldığında, kullanıldığı ortamın viskozite değerini ve tekstürel özelliklerini fazla değiştirmemesi de diğer avantajlarıdır. Lipozom elde etmek için kullanılan polar yağların doğadaki başlıca kaynakları; yumurta ve soya lesitinidir. Bu çalışmada, bu iki kaynaktan elde edilen lesitinlerden hazırlanan lipozomlar hazırlanmış, soya lesiti ile hazırlananların dayanıklılıkları fazla olduğundan bu lipozomların içerisine antioksidan aktivite gösteren fenolik bileşikler kapsüle edilerek, yağ oksidasyonunu engellemek üzere kullanılacak sprey bir ürün elde edilmiştir. Sprey uygulama için oksidasyona hassas bir gıda olan fındık seçilmiştir. Elde edilen ürün, tamamen doğal kaynaklar kullanılarak üretildiği içinuygulandığı gıdaya herhangi bir kimyasal eklenti söz konusu olmamıştır. Sprey ürün geliştirme çalışmaları çerçevesinde öncelikli olarak lipozom sistemlerinin karakterizasyonu yapılmış ve ürününün dayanıklılığı incelenmiştir. Son aşamada elde edilen ürünler fındık üzerine uygulanarak, fındıkların duyusal özellikleri incelenmiştir. Ürünün karakterizasyonu ve fiziksel dayanıklılığın ölçülmesi için tahribatsız bir ölçme tekniği olan Manyetik Rezonans Görüntüleme (MRG) , NMR Relaksometre başlıca metotlar olarak kullanılmış ancak NMR Relaksometre tekniğinin fiziksel özelliklerle daha iyi bir şekilde ilişkilendirildiği görülmüştür. Aynı zamanda karakterizasyon amaçlı, parçacık boyu analizi, zeta potansiyel, ışık mikroskopu teknikleri de kullanılmıştır. Lipozom sistemlerinin kimyasal dayanıklılık testleri için içsel oksidasyonunu ölçmek amacıyla hidroperoksit ölçümleri spektrofotometrik yöntemlerle belirlenmiş, yeşil çay özütülü lipozomlar için antioksidan, fenolik madde miktarı tayinleri de yapılmıştır. Lipozomların dayanıklılıklarını güçlendirmek için biyopolimer kullanarak kaplama da yapılmış ancak kaplamasız lipozomlara göre dayanıklılıkta ciddi bir fark gözlenmemiştir