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排序方式: 共有221条查询结果,搜索用时 15 毫秒
71.
Abstract: This study investigated the influence of an oxygen‐enriched modified atmosphere packaging (HiOx: 80% O2/20% CO2) in comparison with air‐permeable polyvinylchloride (PVC) wrapping and partial vacuum (VP: 60%) packaging on the ability of myofibrils to imbibe water during retail display of fresh ground pork at 2 to 4 °C. Both HiOx and PVC muscles after 4 d showed maximum myofibril swelling and A‐band dissolution when isolated myofibrils were subjected to a graded series of salt solutions (0.2→0.4 M NaCl with 10‐mM sodium pyrophosphate, pH 6.2), while VP samples exhibited no remarkable change. Protein carbonyl content increased substantially from day 0 to 4 in all muscle samples. For HiOx, muscle hydration capacity increased linearly (P < 0.05) during storage up to 14 d, corresponding to protein carbonyl production. No significant changes in hydration properties were noted in VP muscle samples, which also maintained lower levels of protein oxidation, during storage up to 21 d. These results indicated that packaging in modified atmosphere with high levels of oxygen could result in increased protein oxidation but enhanced hydration capacity of fresh meat. Practical Application: Packaging of fresh meat, including ground pork, under an oxygen‐enriched atmosphere condition is widely used in the industry to preserve red color of meat. Results from the present study indicate that high oxygen packaging has a discordant effect on fresh ground pork: it enhances hydration but decreases water‐binding, and this seems to be caused by increased swelling of muscle fibers due to mild protein oxidation. Hence, it is advisable to employ a water‐binding agent in this type of packaging system so as to retain the moisture in stored fresh pork products while maintaining the color stability. 相似文献
72.
A Graphical Method Predicting the Compressive Strength of Toughened Unidirectional Composite Laminates 总被引:1,自引:0,他引:1
The in-plane shear and compressive properties of unidirectional (UD) HTS40/977-2 carbon fibre-toughened resin (CF/TR) laminates
are investigated. Scanning Electron microscopy (SEM) and optical microscopy are used to reveal the failure mechanisms developed
during compression. It is found that damage initiates by fibre microbuckling (a fibre instability failure mode) which then
is followed by yielding of the matrix to form a fibre kink band zone that leads to final fracture. Analytical models are briefly
reviewed and a graphical method, based on the shear response of the composite system, is described in order to estimate the
UD compressive strength. Predictions for the HTS40/977-2 system are compared to experimental measurements and to data of five
other unidirectional carbon fibre reinforced polymer (CFRP) composites that are currently used in aerospace and other structural
applications. It is shown that the estimated values are in a good agreement with the measured results. 相似文献
73.
74.
Stephan Rehm Sigeng Han Ismail Hassani Alma Sokocevic Hendrik R. A. Jonker Dr. Joachim W. Engels Prof. Dr. Harald Schwalbe Prof. Dr. 《Chembiochem : a European journal of chemical biology》2009,10(1):119-127
The protein parvulustat (Z‐2685) from Streptomyces parvulus comprises 78 amino acids and functions as a highly efficient α‐amylase inhibitor. Parvulustat shares 29.6 % overall amino acid sequence identity to the well‐known α‐amylase inhibitor tendamistat. Among the conserved residues are the two disulfide bridges (C9–C25, C43–C70) and the active‐site motif (W16, R17, Y18). Here, we report the high‐resolution NMR structure of parvulustat based on NOEs, J couplings, chemical shifts and hydrogen‐exchange data. In addition, we studied the dynamical properties of parvulustat by heteronuclear relaxation measurements. We compare the structure of parvulustat with the structure of tendamistat in terms of secondary structure elements, charges and hydrophobicity. The overall structural composition is very similar, but there are distinct differences including the active‐site region. These structural and dynamical differences indicate that for parvulustat an induced‐fit mechanism for binding to α‐amylase might take place, since the structure of tendamistat does not change upon binding to α‐amylase. 相似文献
75.
76.
This study deals with an experimental work that aims to examine effects of purified sulfate turpentine obtained from a kraft pulp mill in Turkey on an engine performance and exhaust emissions of a spark ignition engine. Three fuel samples are used to test the performance and emission of a 1300 cc engine manufactured by TOFA?. They are pure gasoline with 98-octane number and two other gasoline-turpentine fuel samples obtained by blending gasoline with turpentine in ratios of 5% and 10% on basis of total mass of the fuel. The thermophysical properties of the fuels are acquired by density, viscosity, flash and fire points, sulphur content, heating value and distillation tests. The experimental results showed that the turpentine has a positive effect on the engine performance parameters, such as brake power, thermal efficiency, mean effective pressure and specific fuel consumption. The turpentine also increases pollutant NOx, unburned hydrocarbon contents and exhaust temperature, but it decreases CO concentration in the exhaust. It is observed that utilization of the sulfate turpentine alone is not viable and it needs to be used as an additive into gasoline to some extent, thereby providing a viable alternative to pure gasoline. 相似文献
77.
Surface modification and immobilization in poly(acrylic acid) of Ag/ZnO for photocatalytic degradation of endocrine‐disrupting compounds
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Alma Berenice Jasso‐Salcedo Dimitrios Meimaroglou Sandrine Hoppe Fernand Pla Vladimir A. Escobar‐Barrios 《应用聚合物科学杂志》2016,133(25)
Silver‐modified ZnO particles (Ag/ZnO) are effective catalysts for the photodegradation of water pollutants such as bisphenol‐A. However, until now, their use in continuous processes was back‐drawn because of difficulties associated with their recovery. To overcome this problem, the present work aimed at immobilizing Ag/ZnO in cross‐linked poly(acrylic acid) ‐PAA‐. Ag/ZnO was first silanized using (3‐glycidyloxypropyl)trimethoxysilane and thoroughly dispersed in a water‐acrylic acid solution. The suspension was then submitted to radical polymerization in presence of a cross‐linker (N,N′‐Methylenebisacrylamide). The resulting composites were characterized in terms of chemical structure, morphology, crystallinity, thermal properties, and photostability. Their analyses showed that the silanized particles were chemically anchored to PAA and homogeneously distributed in the matrix. UV‐assisted photocatalysis of bisphenol‐A aqueous solutions showed that immobilized Ag/ZnO can achieve photodegradation performances comparable to pure Ag/ZnO and allows its use in successive cycles and, consequently, in continuous processes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43528. 相似文献
78.
Laura Benvenuti Vanessa D'Antongiovanni Carolina Pellegrini Matteo Fornai Nunzia Bernardini Chiara Ippolito Cristina Segnani Clelia Di Salvo Rocchina Colucci Alma Martelli Lorenzo Flori Vincenzo Calderone Gianfranca Carta Emilia Ghelardi Marco Calvigioni Adelaide Panattoni Raffaella Coppolecchia Achille Arini Luca Antonioli 《Molecular nutrition & food research》2023,67(13):2200442
Scope
Modifications in intestinal microbiota and its metabolites, the short-chain fatty acids (SCFA) are main factors altering intestinal epithelial barrier integrity and eliciting the onset of a meta-inflammation observed in obesity. The present study is aimed at evaluating the efficacy of Enterococcus faecium (SF68) administration in counteracting the impairment of gut barrier and enteric inflammation in a model of diet-induced obesity, characterizing the molecular mechanisms underlying such beneficial effects.Methods and Results
Male C57BL/6J mice, fed with standard diet (SD) or high-fat diet (HFD), are treated with SF68 (108 CFU day−1). After 8 weeks, plasma interleukin (IL)-1β and lipopolysaccharide binding protein (LBP) are measured, analysis of fecal microbiota composition and butyrate content as well as intestinal malondialdehyde, myeloperoxidase, mucins, tight junction protein, and butyrate transporter expression are investigated. After 8 weeks, SF68 administration counteracts the body weight gain in HFD mice, reducing plasma IL-1β and LBP. In parallel, SF68 treatment acts against the intestinal inflammation in HFD-fed animals and improves the intestinal barrier integrity and functionality in obese mice via the increase in tight junction protein and intestinal butyrate transporter (sodium-coupled monocarboxylate transporter 1 ) expression.Conclusions
Supplementation with SF68 reduces intestinal inflammation and reinforces the enteric epithelial barrier in obese mice, improving the transport and utilization of butyrate. 相似文献79.
Camelo-Méndez GA Camacho-Díaz BH Del Villar-Martínez AA Arenas-Ocampo ML Bello-Pérez LA Jiménez-Aparicio AR 《Journal of the science of food and agriculture》2012,92(13):2709-2714
BACKGROUND: Digital image analysis has an important role in geographical provenance of grains, as it can provide parameters of size, shape and color, which are important quality parameters for the design of engineering processes such as drying and milling of grains. In this study, digital image analysis was used to classify nine rice cultivars based on different morphometric parameters using the three sides of the grain (lateral, ventral and axial), Feret diameter, and 10 different form factors and color parameters (CIE L*, a* and b*). RESULTS: Result of principal component analyisis was an equation with seven variables (area, perimeter, length, width, thickness, sphericity and color), which was useful for distinguishing between nine different cultivars. The morphometric and color parameters for the Mor A‐98 and Mor A‐92 varieties showed they had 88% similarity. The variability was expressed with a confidence of 95%. CONCLUSION: Multivariate analysis indicated that the lateral side is the most sensitive for the classification of Mexican rice grains because of its color and morphometric characteristics. These results showed the application of image analysis for the future classifications of grains. Copyright © 2012 Society of Chemical Industry 相似文献
80.
M. Hakki Alma 《Holz als Roh- und Werkstoff》2008,66(3):237-239
The biodegradability of new molding materials from HCl-catalyzed phenolated wood was investigated
by using some dynamic and static mechanical strength loss methods. 相似文献