压片木糖醇的研究

木糖醇已被作为糖的替代品在某些领域(如口香糖)获得实际生产和商业上的成功.由于其味觉和生产工艺上的先进性,木糖醇的应用非常具有吸引力.木糖醇是一种天然的五碳糖醇,与蔗糖的甜度相当,但热量比较低.在许多水果和蔬菜中发现有少量木糖醇的存在.木糖醇在人体的自然代谢中也会产生.由于其在人体的代谢途径人们已经了解,并具有对口腔及技术性能上的一些特性,使木糖醇更具吸引力.但是木糖醇不能直接可压缩,即晶体木糖醇不能被直接压制成具有足够硬度和较低脆碎度的片剂.因此,为了在压片中应用木糖醇,人们尝试了很多方法来解决这种问题.本文描述了DC级木糖醇的研究进展情况.     

Self-assembly of highly charged polyelectrolyte complexes with superior proton conductivity and methanol barrier properties for fuel cells

The paper is concerned with the formation of Layer-by-Layer (LbL) self-assembly of highly charged polyvinyl sulfate potassium salt (PVS) and polyallylamine hydrochloride (PAH) on Nafion membrane to obtain the multilayered composite membranes with both high proton conductivity and methanol blocking properties. Also, the influences of the salt addition to the polyelectrolyte solutions on membrane selectivity (proton conductivity/methanol permeability) are discussed in terms of controlled layer thickness and charge density.The deposition of the self-assembly of PAH/PVS is confirmed by SEM analysis and it is observed that the polyelectrolyte layers growth on each side of Nafion membrane regularly. (PAH/PVS)₁₀-Na⁺ and (PAH/PVS)₁₀-H⁺ with 1.0 M NaCl provide 55.1 and 43.0% reduction in lower methanol permittivity in comparison to pristine Nafion, respectively, while the proton conductivities are 12.4 and 78.3 mS cm⁻¹. Promisingly, it is found that the membrane selectivity values (Φ) of all multilayered composite membranes in H⁺ form are much higher than those of Na⁺ form and perfluorosulfonated ionomers reported in the literature. These encouraging results indicate that composite membranes having both superior proton conductivity and improved methanol barrier properties can be prepared from highly charged polyelectrolytes including salt for fuel cell applications.     

Metals (major,essential to non-essential) composition of the different tissues of three demersal fish species from İskenderun Bay,Turkey

This study was performed to investigate certain major and toxic metal concentrations in different tissues of three demersal fish species (Triglia lucerna, Lophius budegassa, Solea lascaris). Generally, skin and liver exhibited higher metal concentrations than did muscle. Sodium and arsenic concentrations were found at higher levels in muscle tissues than in livers and skin, while zinc and nickel in different organs were classified as follows: skin > liver > muscle tissues. The concentrations of trace metals in fish samples indicated that S. lascaris was more contaminated than were other fish species, followed by L. budegassa and T. lucerna. It may be concluded that consumption of these species from this region is not likely to pose a threat for human health. However, although the concentrations are below the limit values for fish muscles, a potential danger may emerge in the future, depending on domestic waste waters and industrial activities in the region. Therefore, further monitoring programmes should be conducted.     

Subcooled Flow Boiling Over Microstructured Plates In Rectangular Minichannels

Microstructures offer enhancements in boiling heat transfer by increasing bubble departure frequency, active nucleation site density, critical cavity size, and surface area. Integration of microstructures to surfaces alters significant surface parameters such as porosity of the microstructured plates, contact angle, and configuration of microstructures on the surface, which all affect boiling heat transfer. The goal of this study is to investigate boiling heat transfer on different microstructured plates and the effect of various microscale surface morphologies on boiling heat transfer. The microstructured surfaces were formed on aluminum alloy 2024 sheets with the use of a simple and environmentally friendly technique of random mechanical sanding (grits of #36, #60, #400, and #1,000). Distilled water was pumped using a micro gear pump to the rectangular minichannel test section at flow rates of 100, 180, and 290 ml/min, which correspond to mass fluxes of 5.46, 10.58, and 16.15 kg/m².s, respectively. It was observed that surfaces with low grit (grit #36) showed no considerable enhancement, whereas the use of higher grit counts considerably enhanced boiling heat transfer up to a critical grit count. The results were supported by the images from the performed visualization of flow boiling.     

Effect of Extraction Methods on the Properties of Althea Officinalis L. Fibers

In this study, the effect of extraction methods on the properties of Althea officinalis l. (marshmallow) fibers was investigated. For this purpose, obtaining the fibers from stem was done by water and chemical extraction. After the extraction process, mechanical and thermal properties of althea fibers were investigated and morphological structure was examined. Crystallinity indexes (CI) of fibers were determined. Scanning electron microscopy results revealed that extraction of althea officinalis fibers by alkali boiling in 5% NaOH solution led to removal of surface impurities and also according to X-ray diffraction results, crystallinity index of fibers was improved by 14%. Chemically extracted fibers showed 37% higher tensile strength when compared to water extracted fibers. Density measurements revealed that chemically retted fibers have higher density. Also, Fourier Transform Infrared Spectroscopy analysis showed that chemical extraction caused change of chemical composition by decreasing and/or disappearing of some peaks which belong to hemicellulose and lignin.     

Advanced retorting,microwave assisted thermal sterilization (MATS), and pressure assisted thermal sterilization (PATS) to process meat products

Conventional thermal processes have been very reliable in offering safe sterilized meat products, but some of those products are of questionable overall quality. Flavor, aroma, and texture, among other attributes, are significantly affected during such processes. To improve those quality attributes, alternative approaches to sterilizing meat and meat products have been explored in the last few years. Most of the new strategies for sterilizing meat products rely on using thermal approaches, but in a more efficient way than in conventional methods. Some of these emerging technologies have proven to be reliable and have been formally approved by regulatory agencies such as the FDA. Additional work needs to be done in order for these technologies to be fully adopted by the food industry and to optimize their use. Some of these emerging technologies for sterilizing meat include pressure assisted thermal sterilization (PATS), microwaves, and advanced retorting. This review deals with fundamental and applied aspects of these new and very promising approaches to sterilization of meat products.     

Phenolics profiles of olive fruits (Olea europaea L.) and oils from Ayvalık,Domat and Gemlik varieties at different ripening stages

Phenolic compounds in olive fruit and oils obtained from Ayval?k, Domat and Gemlik olive varieties collected at different ripening periods were evaluated by High Performance Liquid Chromatography (HPLC). Gallic acid and p-cumaric acid were identified for Ayval?k and Domat at each period of ripening, respectively. In addition, gallic acid, p-cumaric acid, sinapinic and apigenin acids were detected in Gemlik olive fruit. Hydroxytyrosol, rutin, oleoropein, luteolin, tyrosol, vanilic acid and gallic acid in Ayval?k olive fruit in all ripening periods were determined. The tyrasol contents varied between 0.18 to 1.57 mg/kg. Luteolin contents of olive oils ranged at the levels between 0.12 to 2.28 mg/kg. In contrast, oils had the lowest syringic, p-cumaric, chlorogenic and ferulic acids. Vanillic acid contents of oils ranged between 0.08 to 2.38 mg/kg.