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91.
Lipoprotein lipase (LPL) activity and free fatty acid levels were studied in freshly milked, uncooled milk from individual Danish Holstein or Jersey cows, or after storage for up to 24 h at either a cooling temperature (4°C) or at the milking temperature (31°C). Upon cooling for up to 24 h, LPL activity increased in the cream phase, whereas the activity in the skim milk was steady, as observed for Jersey cows, or increased, as seen for the Holsteins. Storage at 31°C decreased the LPL activity in both the cream phase and the skim milk phase. The increase in free fatty acid levels was found to depend on LPL activity, incubation temperature, substrate availability, and incubation time. Furthermore, the migration of milk proteins between the skim milk phase and the cream phase upon cooling of milk from Jersey cows or from Danish Holstein cows was studied using proteomic methods involving 2-dimensional gel electrophoresis and mass spectrometry. Proteins associated with the milk fat globules were isolated from all milk fractions and analyzed. Major changes in the distributions of proteins between the skim milk phase and the cream phase were observed after cooling at 4°C for 4 h, where a total of 29 proteins between the 2 breeds was found to change their association with the milk fat globule membrane (MFGM) significantly. Among these, the MFGM proteins adipophilin, fatty acid-binding protein, and lactadherin, as well as the non-MFGM proteins β-casein, lactoferrin, and heat shock protein-71, were identified. Adipophilin, lactadherin, and lactoferrin were quantitatively more associated with the MFGM upon cold storage at 4°C, whereas β-casein, fatty acid-binding protein, and heat shock protein-71 were found to be less associated with the MFGM upon cold storage. 相似文献
92.
Søltoft M Bysted A Madsen KH Mark AB Bügel SG Nielsen J Knuthsen P 《Journal of the science of food and agriculture》2011,91(4):767-775
BACKGROUND: The demand for organic food products has increased during the last decades due to their probable health effects, among others. A higher content of secondary metabolites such as carotenoids in organic food products has been claimed, though not documented, to contribute to increased health effects of organic foods. The aim was to study the impact of organic and conventional agricultural systems on the content of carotenoids in carrots and human diets. In addition, a human cross‐over study was performed, measuring the plasma status of carotenoids in humans consuming diets made from crops from these agricultural systems. RESULTS: The content of carotenoids in carrot roots and human diets was not significantly affected by the agricultural production system or year, despite differences in fertilisation strategy and levels. The plasma status of carotenoids increased significantly after consumption of the organic and conventional diets, but no systematic differences between the agricultural production systems were observed. CONCLUSION: The expected higher content of presumed health‐promoting carotenoids in organic food products was not documented in this study. Copyright © 2011 Society of Chemical Industry 相似文献
93.
J. M. Schmidt M. Greve-Poulsen H. Damgaard A. V. Sunds Z. Zdráhal M. Hammershøj L. B. Larsen 《Food and Bioprocess Technology》2017,10(11):1946-1958
In an effort to purify potato proteins of superior food grade quality, a new procedure involving anion exchange (ion exchange (IEX)) and hydrophobic interaction chromatography (HIC) was established. Liquid potato fruit juice (PFJ) or re-suspended spray-dried protein was separated by IEX yielding two fractions: a protease inhibitor (PI)-rich fraction and a patatin-rich fraction. Each of these fractions was re-chromatographed on HIC, resulting in two new sub-fractions which were characterised by electrophoresis and mass spectrometry. A high-quality powder should have high lightness, low polyphenol oxidase (PPO) activity and glycoalkaloid content below 150 μg/g. The PI fraction from spray-dried powder had high lightness (L* = 83) compared to patatin (L* = 50), whereas IEX purification from PFJ resulted in a PI fraction with decreased lightness (L* = 66) and a patatin fraction with increased lightness (L* = 68). HIC fractionation led to increased lightness for patatin fraction, but decreased lightness for the PFJ PI fractions. HIC purification significantly lowered PPO activity in the fractions due to its selective affinity. The lowest total glycoalkaloid content was generally found in HIC fractions from spray-dried powder (150 μg/g), while high levels (>1000 μg/g) were found in PI fractions from PFJ. In conclusion, it was possible to obtain a PI-rich protein isolate from powder with good-quality attributes after both IEX and HIC, while for patatin, the best quality was obtained after the HIC only, and there, the colour or PPO activity may still be a problem depending on source material. 相似文献
94.
A theory of the effect of gas bubbles upon parallel-surfaced hydrodynamic bearings is presented.The analysis applies to “infinitely” wide isothermal bearings, but conclusions are also drawn on the behaviour of finite bearings. It is shown that no self-sustained pressure is established, but that a pressure profile generated otherwise can be strongly modified to yield a near doubling of the load capacity and unaltered friction; and for a fixed load, lowered friction and increased mass flow through the bearing. 相似文献
95.
Mikael B. Skov Jesper Kjeldskov Jeni Paay Niels Husted Jacob Nørskov Kenneth Pedersen 《Pervasive and Mobile Computing》2013,9(2):216-227
Some movements within modern architecture particularly emphasise the importance of matching buildings to their surroundings. However, practicing such “contextual architecture” is highly challenging and typically not something the future inhabitants of a building are well equipped for participating in. This paper explores the potentials of using mobile phone technology for facilitating such client participation in the parts of an architecture process that take place on the building site. For this we introduce ArchiLens, a mobile system for interactive on-site 3D visualisation of houses, and findings from a field study with 40 participants in the process of building or modifying their home. The study showed that using the system helped evoke people’s imagination of the look and feel of their future house, and envision it in context. This enabled them to participate more closely in the design process on-site by iteratively reviewing design alternatives and exploring, for example, other placements and materials. 相似文献
96.
Maria João Cardoso Anca Ioana Nicolau Daniela Borda Line Nielsen Rui Leandro Maia Trond Møretrø Vânia Ferreira Susanne Knøchel Solveig Langsrud Paula Teixeira 《Comprehensive Reviews in Food Science and Food Safety》2021,20(3):2716-2741
Nontyphoidal salmonellae are among the most prevalent foodborne pathogens causing gastrointestinal infections worldwide. A high number of cases and outbreaks of salmonellosis are associated with the consumption of eggs and egg products, and several of these occur at the household level. The aim of the current study is to critically evaluate the current status of knowledge on Salmonella in eggs from a consumer's perspective, analyzing the hazard occurrence and the good practices that should be applied to reduce salmonellosis risk. Following a HACCP (Hazard Analysis and Critical Control Point) based approach, some steps along the food journey were identified as Critical Consumer Handling (CCH)—steps in which consumers, through their behavior or choice, can significantly reduce the level of Salmonella in eggs and egg products. From shopping/collecting to consumption, each of these steps is discussed in this review to provide an evidence-based overview of risk factors of human salmonellosis related to egg consumption. The main message to consumers is to choose Salmonella-free eggs (those that some official entity or producer guarantees that does not contain Salmonella), when available, especially for dishes that are not fully heat treated. Second, as guaranteed Salmonella-free eggs are only available in a few countries, refrigerated storage from the point of collection and proper cooking will significantly reduce the risk of salmonellosis. This will require a revision of the actual recommendations/regulations, as not all ensure that eggs are maintained at temperatures that prevent growth of Salmonella from collection until the time of purchasing. 相似文献
97.
Ehsan Houshfar Liang Wang Niklas Vähä-Savo Anders Brink Terese Løvås 《Clean Technologies and Environmental Policy》2014,16(7):1339-1351
Bioenergy is considered as a sustainable energy which can play a significant role in the future’s energy scenarios to replace fossil fuels, not only in the heat production, but also in the electricity and transportation sectors. Emission formation and release of main ash-forming elements during thermal conversion of biomass fuels at different conditions have been the scope of this study. The experiments were conducted in a quartz glass reactor where the temperature and atmosphere could be controlled. The selected fuels represent a wide range of biomass compositions. They are torrefied softwood, spruce bark, waste wood, miscanthus, and wheat straw. The fuels were first grinded and then pressed with a pellet maker into pellets of the same size and weight. For each fuel, the experiments were carried out under both oxidation and pyrolysis condition, with atmosphere of 3 % O2 + 97 % N2 and 100 % N2, respectively, at four residence times. The selected temperatures under which experiments were performed are 800, 900, and 1,050 °C. The concentration of SO2, NO, CO, and CO2 emissions and O2 were monitored online by three analysers, simultaneously. The residue weight was measured after each process, and the comparison with the ash content of the fresh pellet is made. Additionally, the release of several ash-forming elements (K, Zn, Na, and Mn) from the fuels has been quantified as function of temperature and residence time by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Time-dependent formation of NO and SO2 and other emissions is presented and discussed with respect to different temperature and combustion conditions. 相似文献
98.
99.
Duc‐The Ngo Roberto Scipioni Søren Bredmose Simonsen Peter Stanley Jørgensen Søren Højgaard Jensen 《国际能源研究杂志》2016,40(14):2022-2032
LiFePO4‐based cathodes suffer from various degradation mechanisms, which influences the battery performance. In this paper, morphological and structural degradation phenomena in laboratory cathodes made of LiFePO4 mixed with carbon black (CB) in a 1 mol/L LiPF6 in EC : DMC (1:1 by weight) electrolyte are investigated by transmission electron microscopy at various preparation, assembling, storage, and cycling stages. High‐resolution transmission electron microscopy imaging shows that continuous SEI layers are formed on the LiFePO4 particles and that both storage and cycling affect the formation. Additionally, loss of CB crystallinity, CB aggregation, and agglomeration is observed. Charge–discharge curves and impedance spectra measured during cycling confirm that these degradation mechanisms reduce the cathode conductivity and capacity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
100.
Torbjørn H. Netland 《国际生产研究杂志》2016,54(8):2433-2448
To facilitate the implementation of lean production, practitioners and researchers have suggested an array of critical success factors (CSFs). However, despite a broad consensus about what needs to be done, companies still struggle to implement lean. Contingency theory posits the explanation that the common advice is not universal but is instead contingent on the situation. This paper investigates how contingency variables influence what practitioners see as success factors for implementing lean. A survey asked 432 practitioners from 83 factories belonging to two multinational companies for their opinions about what managers should do to ensure the success of the factory-level implementation of lean production. The survey responses were grouped into general success factors, which were then tested for differences across four contingency variables: corporation, factory size, stage of lean implementation and national culture. In general, the analysis supports a generic list of CSFs, but with some minor exceptions. For example, the stage of lean implementation in a factory influences to a slight extent which factors are perceived as more effectual than others. The paper contributes to the literature on lean production and offers several recommendations for managers striving to implement lean in their firms. 相似文献