首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 10 毫秒
1.
The use of walnut or peanut in the elaboration of cereal bars represents a possible risk of undesirable changes during their storage due to their high content of unsaturated fatty acids in the oil; oxidizing of the fatty acids is one of the main causes of deterioration. Development of new snack products implies the use of packages that should protect the food against the damage caused by light and reduce the oxygen concentration of in their interior. The objective of this investigation was to evaluate the physical, chemical and sensory changes in the storage of cereal bars with peanut or walnut and mezquite cotyledon subjected to two thermal treatments, packed in cellophane or milky polypropilene. Four types of bars were elaborated with 6% of mezquite cotyledon, treated by microwaves or toasted, and with 18% of peanut or walnut. The bars were stored for 90 days at room temperature; and each 30 days it was measured moisture content, peroxides index, water activity, sensory quality and acceptability. The peroxides values (4.9-13.8 meq/kg of oil) indicates that the shelf life of the bars in all the studied treatments was 90 days. The packaging materials used allows to maintain in good conditions, for 3 months, the cereals bars of moisture (7.4-11.2%), water activity (0.50-0.65) and sensory acceptability.  相似文献   

2.
The impact of metal nanoparticles (NPs) on biological systems, especially plants, is still not well understood. The aim of this research was to determine the effects of zinc oxide (ZnO) NPs in velvet mesquite (Prosopis juliflora-velutina). Mesquite seedlings were grown for 15 days in hydroponics with ZnO NPs (10 nm) at concentrations varying from 500 to 4000 mg L(-1). Zinc concentrations in roots, stems and leaves were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES). Plant stress was examined by the specific activity of catalase (CAT) and ascorbate peroxidase (APOX); while the biotransformation of ZnO NPs and Zn distribution in tissues was determined by X-ray absorption spectroscopy (XAS) and micro X-ray fluorescence (μXRF), respectively. ICP-OES results showed that Zn concentrations in tissues (2102 ± 87, 1135 ± 56, and 628 ± 130 mg kg(-1) d wt in roots, stems, and leaves, respectively) were found at 2000 mg ZnO NPs L(-1). Stress tests showed that ZnO NPs increased CAT in roots, stems, and leaves, while APOX increased only in stems and leaves. XANES spectra demonstrated that ZnO NPs were not present in mesquite tissues, while Zn was found as Zn(II), resembling the spectra of Zn(NO(3))(2). The μXRF analysis confirmed the presence of Zn in the vascular system of roots and leaves in ZnO NP treated plants.  相似文献   

3.
4.
Excavation works were carried out in Boom Clay to extend the underground research facility in Mol (Belgium) located at a depth of 223 m below the surface. The attempt to characterise the extent of the Excavation Damaged Zone, or EDZ, around the second shaft, using seismic measurements and cored borings, was successful, as proven by observations during further excavation works in the investigated area. No evidence for the occurrence of natural discontinuities was found. Using an industrial technique, an 84-m-long gallery was excavated in the Boom Clay. These excavation works induced a symmetrical pattern of discontinuities and clearly limited the EDZ extent.  相似文献   

5.
Recently, drug personalization has received noticeable attention. Problems arising from standard generalized drug treatments have aroused over the years, particularly among pediatric and geriatric patients. The growing awareness of the limitations of the “one-size-fits-all” approach has progressively led to a rethinking of the current medicine's development, laying the basis of personalized medicine. Three-dimensional printing is a promising tool for realizing personalized therapeutic solutions fitting specific patient needs. This technology offers the possibility to manufacture drug delivery devices with tailored doses, sizes, and release characteristics. Among additive manufacturing techniques, fused deposition modeling (FDM) is the most studied for oral drug delivery device production due to its high precision and cheapness. By playing with factors such as drug loading method, filament production, and printing parameters, the medication release profile of a drug delivery device produced by 3D printing can be tailored depending on the patient's requirements. This review focuses on the applications of FDM in drug fabrication using poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) as drug-loaded matrices. The authors aim to provide an overview of the current trends in this research field, with special attention to the effect of the printing parameters, tablet shape, and drug distribution and concentration on drug customization and personalized drug release.  相似文献   

6.
ABSTRACT

The encapsulation properties of pure mesquite and arabic gum powders and mixtures thereof with orange peel oil were measured. The highest rate of encapsulated oil was found to be 93.5 % for a ratio of 60.40% of arabic to mesquite gums. Pure arabic gum preparations were able to encapsulate similar amounts of the oil. Sensory evaluvation of the microencapsulates showed no significant differences (a≤.05) in flavor intensity beween orange peel oil encapsulated with pure arabic gum and mixtures containing mesquite gum.  相似文献   

7.
8.
9.
A relatively new method to manufacture complex ceramic prototypes and components is additive manufacturing (AM). With the LCM (Lithography-based Ceramic Manufacturing)-technology the green body is manufactured layer-by-layer using selective curing of light-sensitive ceramic slurry by a mask exposure process. After curing by blue light the component is removed from the building platform and the green body is sintered to a ceramic component.The aim of this work is to investigate the influence of processing and layer architecture on the mechanical properties of an Yttria-stabilized zirconia ceramic. Strength tests were performed by uniaxial bending tests and by biaxial Ball-on-three Balls (B3B) tests. To identify typical fracture initiating flaws a systematic fractographic investigation was performed on different batches of Ball-on-three Balls-test and bending test specimens, respectively.Through additional investigations it was found that hardness and fracture toughness were independent on the layer architecture. But an extensive fractographic analysis showed that the strength was limited by flaws, which were introduced by processing and handling. If these flaws can be avoided by optimisation of the process the strength should be equal to that of conventional processed ceramics.  相似文献   

10.
The effect of the addition of rosa mosqueta husk extract (RME) on thermal oxidation of nontreated (HZO) and treated (THZO) Chilean hazelnut seed oil was evaluated at 180°C for 18 h. THZO to which was added 339 mg/kg of α-tocopherol was used as a comparison model because RME supplied 314 mg/kg of α-tocopherol. Formation of polar compounds and degradation of tocols and carotenoid, pigments were studied in these model systems. Degradation of trans-rubixanthin, trans-lycopene, and trans-β-carotene followed a pseudo first-order kinetics model. These pigments showed the same degradation rate in both HZO and THZO. The addition of RME to HZO and THZO decreased significantly (P<0.05) the formation of polar compounds, lead to less degradation of tocols, and improved their oxidative stability with respect to oils without RME. This behavior can be attributed to carotenoid-tocopherol interaction, suggesting that these pigments can protect tocols against degradation at high temperature.  相似文献   

11.
Conclusions The technology of treatment of active sludge is simple, but requires strict observance of the rules of safety technique in work with harmful substances (mutagens).The chemical mutagenesis method is selective and requires microbiological control over the operation of biological clean-up installations.Wastewater which has been cleaned up using the chemical mutagenesis method has an extremely low degree of toxicity.Translated from Khimicheskie Volokna, No. 4, pp. 56–57, July–August, 1989.  相似文献   

12.
13.
A study was conducted to evaluate mica-poly(vinyl chloride) (PVC) composites. A highly filled PVC pipe formulation was selected as reference and a gradual replacement by mica of the calcium carbonate was conducted. The mica improved the fluxing time of the formulation by a factor of three without markedly affecting the equilibrium or maximum, torque. The results are optimized when there is a partial replacement of the calcium carbonate by mica, Orientation of the mica flakes enhances the young's modulus as well as the yield stress. A theoretical analysis shows a discrepancy from experimental results for high levels of mica. The rheological properties were studied with a Brabender plastograph and mechanical properties with a model TM-SM Instron.  相似文献   

14.
C10芳烃的开发利用   总被引:2,自引:0,他引:2  
C10芳芳烃资源集中,用途广泛,蕴茂着巨大经济效益。C10芳烃的开发已引起国内外的重视。本文重点概述了国内我生产技术和今后发展趋势,以及C10芳烃综合利用的经济效益,为C10芳烃的开发利用提供可参考的意见。  相似文献   

15.
16.
吴贻珍 《中国橡胶》2010,26(6):29-33
<正>带传动是机械传动重要的传动形式之一,随着工业技术水平的不断提高,以及对机械设备精密化、轻量化、功能化和个性化的要求,不断向高精度、高速度、大功率、高效率、高可靠性、长寿命、低  相似文献   

17.
本文讨论了2-硝基三氟甲基苯腈(NCB)的先进生产工艺,并对该产品的技术指标,技术关键及经济效益进行了分析探讨。该生产工艺得到的NCB产品不但填补了国内空白,而且产生巨大的经济效益和社会效益,是一种值得投资开发的优秀精细化工产品。  相似文献   

18.
Summary Poly(styrene)-block-poly(ethyleneoxide), abbreviated as (PS-b-PEO) were used as emulsifiers in emulsion polymerization of styrene and methyl methacrylate. The block copolymers had a poly(styrene) block with Mn=1000 g/mol and a poly(ethyleneoxide) block with Mn=1000, 3000 or 5000 g/mol, respectively. Stable dispersions were obtained when the PEO block molecular weight was higher than 1000 g/mol. Also the amphiphilic properties of the copolymers depended on the PEO chain length. Block copolymer micelles with hydrodynamic radii between 11 and 17nm were observed. Emulsion polymerization was performed at different block copolymer concentration at 60 and 80°C. Particle size varied between 50 and 300nm and decreased with increasing copolymer concentration. The particle size was larger at higher temperature, but the size distribution was narrower. Polymerization of methyl methacrylate gave smaller particles when compared to styrene. The dispersions were very stable towards high electrolyte concentration, but flocculation occurred at elevated temperatures. Both observations indicate that the dispersions are sterically stabilized.  相似文献   

19.
Conventional reinforcing steel is used in the majority of reinforced concrete structures. In general, steel reinforcement meeting ASTM A615 specifications has been the predominant reinforcement used for these structures. Low-alloy reinforcing steel (ASTM A706) was developed and is being marketed to improve ductility and weldability deficiencies associated with the ASTM A615 reinforcement. Several State Highway Agencies have adopted the use of these low-alloy reinforcing steels. Limited research has been performed on the corrosion characteristics of the steel reinforcement meeting ASTM A706 specifications. This paper presents results from a laboratory study on the critical chloride threshold, macrocell corrosion rates, and mass loss testing for ASTM A706 and ASTM A615 reinforcing steels embedded in concrete and exposed to chloride solution. Results from this study indicate that ASTM A706 reinforcing steel exhibits lower critical chloride threshold levels and higher corrosion rates than ASTM A615 reinforcing steel when embedded in cementitious materials.  相似文献   

20.
介绍聚偏氯乙烯生产和吹膜过程中产生的废弃物回收利用的几个实例,说明在使用聚偏氯乙烯时要充分利用其使用价值。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号