Home About us Contact
|
Home About us Contact | ||
|
|
||
Quality Deterioration (quality + deterioration)
Kinds of Quality Deterioration Selected AbstractsRestructuring Uganda's Coffee Industry: Why Going Back to Basics MattersDEVELOPMENT POLICY REVIEW, Issue 4 2006John Baffes After experiencing a boom during the mid-1990s, the performance of Uganda's coffee industry has been disappointing. Most existing analysis sees the sector's problems as quality deterioration, a poor marketing position in the global market, a weak regulatory framework, and poor infrastructure. Recommendations range from setting up a coffee auction to increasing the share of specialty coffees. This article concludes that such advice has been largely inconsistent with the stylised facts of the Uganda coffee industry, and it argues that coffee wilt disease and the effectiveness of the coffee replanting programme are the two key issues on which policymakers and the donor community should focus their activities and allocate their resources. [source] Assessing the results of scenarios of climate and land use changes on the hydrology of an Italian catchment: modelling studyHYDROLOGICAL PROCESSES, Issue 19 2010Daniela R. D'Agostino Abstract Hydrological models are recognized as valid scientific tools to study water quantity and quality and provide support for the integrated management and planning of water resources at different scales. In common with many catchments in the Mediterranean, the study catchment has many problems such as the increasing gap between water demand and supply, water quality deterioration, scarcity of available data, lack of measurements and specific information. The application of hydrological models to investigate hydrological processes in this type of catchments is of particular relevance for water planning strategies to address the possible impact of climate and land use changes on water resources. The distributed catchment scale model (DiCaSM) was selected to study the impact of climate and land use changes on the hydrological cycle and the water balance components in the Apulia region, southern Italy, specifically in the Candelaro catchment (1780 km2). The results obtained from this investigation proved the ability of DiCaSM to quantify the different components of the catchment water balance and to successfully simulate the stream flows. In addition, the model was run with the climate change scenarios for southern Italy, i.e. reduced winter rainfall by 5,10%, reduced summer rainfall by 15,20%, winter temperature rise by 1·25,1·5 °C and summer temperature rise by 1·5,1·75 °C. The results indicated that by 2050, groundwater recharge in the Candelaro catchment would decrease by 21,31% and stream flows by 16,23%. The model results also showed that the projected durum wheat yield up to 2050 is likely to decrease between 2·2% and 10·4% due to the future reduction in rainfall and increase in temperature. In the current study, the reliability of the DiCaSM was assessed when applied to the Candelaro catchment; those parameters that may cause uncertainty in model output were investigated using a generalized likelihood uncertainty estimation (GLUE) methodology. The results showed that DiCaSM provided a small level of uncertainty and subsequently, a higher confidence level. Copyright © 2010 John Wiley & Sons, Ltd. [source] Marine and human activity influences on the groundwater quality of southern Korinthos area (Greece)HYDROLOGICAL PROCESSES, Issue 12 2003G. Stamatis Abstract In this paper the groundwater quality of the southern part of Korinthos region (north-east Peloponnese) is discussed. The geology is characterized by a thick sequence of Neogene marls alternating with sandstones, overlain by superficial Quaternary deposits. The latter consist of a mixture of loose materials such as conglomerates, marly sandstones, sands and clay to silty sands. The area is crossed by a fault system parallel to the coastline, and the Quaternary sediments have formed extended Tyrrhenian marine terraces. Two aquifers have been identified in the area. The first is unconfined and occurs within the Quaternary sediments whereas the other is a deep confined aquifer occurring within the underlying Neogene marl series. Analysis of hydrochemical evolution over the past 30 years has indicated significant deterioration of quality owing to seawater intrusion and nitrate pollution. The various sources of pollution have rendered, to a large extent, shallow groundwater unsuitable not only for potable water supply but also for irrigation purposes. However, this is not the case for the deeper confined aquifer. Statistical analysis was used to explore the evolution of salinization during the years 1968 and 1998. In view of the alarming conditions caused by the documented groundwater quality deterioration, the need for integrated water resources management is stressed to maintain the socio-economic growth of the region studied. Copyright © 2003 John Wiley & Sons, Ltd. [source] The behavior of emerging market sovereigns' credit default swap premiums and bond yield spreadsINTERNATIONAL JOURNAL OF FINANCE & ECONOMICS, Issue 1 2010Michael Adler Abstract We test whether credit risk for Emerging Market Sovereigns is priced equally in the credit default swap (CDS) and bond markets. The parity relationship between CDS premiums and bond yield spreads (BYS), that was tested and largely confirmed in the literature, is mostly rejected. Prices below par can result in positive basis, i.e. CDS premiums that are greater than BYS and vice versa. To adjust for the non-par price, we construct the BYS implied by the term structure of CDS premiums for various maturities. We are able to restore the parity relation and confirm the equivalence of credit risk pricing in the CDS and bond markets for many countries that have bonds with non-par prices and time varying credit quality. We detect non-parity even after the adjustment mainly in countries in Latin America, where the bases are larger than the bid,ask spreads in the market. We also find that the repo rates of bonds decrease around episodes of credit quality deterioration, which helps the basis remain positive. Copyright © 2009 John Wiley & Sons, Ltd. [source] The relationships between stocking density and welfare in farmed rainbow troutJOURNAL OF FISH BIOLOGY, Issue 3 2002T. Ellis There is increasing public, governmental and commercial interest in the welfare of intensively farmed fish and stocking density has been highlighted as an area of particular concern. Here we draw scientific attention and debate to this emerging research field by reviewing the evidence for effects of density on rainbow trout. Although no explicit reference to ,welfare' has been made, there are 43 studies which have examined the effects of density on production and physiological parameters of rainbow trout. Increasing stocking density does not appear to cause prolonged crowding stress in rainbow trout. However, commonly reported effects of increasing density are reductions in food conversion efficiency, nutritional condition and growth, and an increase in fin erosion. Such changes are indicative of a reduced welfare status,although the magnitude of the effects has tended to be dependent upon study-specific conditions. Systematic observations on large scale commercial farms are therefore required, rather than extrapolation of these mainly small-scale experimental findings. There is dispute as to the cause of the observed effects of increasing density, with water quality deterioration and/or an increase in aggressive behaviour being variously proposed. Both causes can theoretically generate the observed effects of increasing density, and the relative contribution of the two causes may depend upon the specific conditions. However, documentation of the relationship between density and the effects of aggressive behaviour at relevant commercial densities is lacking. Consequently only inferential evidence exists that aggressive behaviour generates the observed effects of increasing density, whereas there is direct experimental evidence that water quality degradation is responsible. Nevertheless, there are contradictory recommendations in the literature for key water quality parameters to ensure adequate welfare status. The potential for welfare to be detrimentally affected by non-aggressive behavioural interactions (abrasion, collision, obstruction) and low densities (due to excessive aggressive behaviour and a poor feeding response) have been largely overlooked. Legislation directly limiting stocking density is likely to be unworkable, and a more practical option might be to prescribe acceptable levels of water quality, health, nutritional condition and behavioural indicators. [source] PRESERVATION OF COMMERCIAL FISH BALL QUALITY WITH EDIBLE ANTIOXIDANT-INCORPORATED ZEIN COATINGSJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 5 2009LIAN-SYUN LIN ABSTRACT Fish ball, a surimi product rich in lipid and protein, is a popular food in Taiwan. Because lipid oxidation is one of the major deterioration reactions for fish ball, the feasibility of preservation of fish ball quality by the application of antioxidant-incorporated zein coating was investigated. Three antioxidants including butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and n-propyl gallate (PG) were used to formulate the antioxidant zein coatings. Infrared spectroscopy was used to confirm the successful incorporation of antioxidant with zein protein; peroxide value (POV), thiobarbituric acid reactive substance (TBARS) and weight loss were used as the quality indicators of fish ball stored at 4C. While all three types of antioxidant-incorporated zein coatings significantly retarded the quality deterioration, PG-incorporated zein coating exerted better quality preservation effectiveness than BHA- and BHT-incorporated zein coatings. PRACTICAL APPLICATIONS Edible coatings have been under research for several decades. However, most of the studies are conducted for the investigations of physiochemical or mechanical properties and usually using simulated food systems. The lack of applications on the commercial food products manufactured from food plants makes the edible coatings somewhat unrealistic. Not prepared in a laboratory for academic purpose only, the fish ball used in the present study was a real commercial product. The promising results of antioxidant-incorporated zein coatings on commercial products presented in this report will enhance the confidence of food manufacturers on the edible coatings. [source] EFFECTS OF PRESTORAGE DRY AND HUMID HOT AIR TREATMENTS ON THE QUALITY, TRIGLYCERIDES AND TOCOPHEROL CONTENTS IN ,HASS' AVOCADO FRUITJOURNAL OF FOOD QUALITY, Issue 2 2004J. DE JESUS ORNELAS P. ABSTRACT ,Hass' avocado fruit were heated with dry (50% RH) or moist (95% RH) forced air at 38Cfor 6 h and then stored at 5C and 85% RHfor up to 8 weeks. Fruit were evaluated weekly for quality and for the content of three triglycerides and three tocopherols. Heated fruit had higher weight loss. The nonheated fruit and those heated with dry air displayed the best external quality. Fruit heated with dry air exhibited the best internal quality and the lowest chilling injury incidence. The respiration rate was more intense in fruit heated with moist air. Fruit firmness immediately after harvest was 51N, but decreased to less than 20 N at the end of the storage period in the three treatments. The analysis of triglycerides and tocopherols showed that the 1,2-Dilinoleil-3-Oleil-Glycerol and ,-tocopherol were the most abundant compounds. Therefore, postharvest treatment with dry forced hot air before storage or transport reduces the incidence of chilling injury, and decreases quality deterioration in ,Hass' avocado fruit. [source] Effect of Storage Temperature and Duration on the Behavior of Escherichia coli O157:H7 on Packaged Fresh-Cut Salad Containing Romaine and Iceberg LettuceJOURNAL OF FOOD SCIENCE, Issue 7 2010Yaguang Luo Abstract:, This study investigated the impact of storage temperature and duration on the fate of Escherichia coli O157:H7 on commercially packaged lettuce salads, and on product quality. Fresh-cut Romaine and Iceberg lettuce salads of different commercial brands were obtained from both retail and wholesale stores. The packages were cut open at one end, the lettuce salad inoculated with E. coli O157:H7 via a fine mist spray, and resealed with or without an initial N2 flush to match the original package atmospheric levels. The products were stored at 5 and 12 °C until their labeled "Best If Used By" dates, and the microbial counts and product quality were monitored periodically. The results indicate that storage at 5 °C allowed E. coli O157:H7 to survive, but limited its growth, whereas storage at 12 °C facilitated the proliferation of E. coli O157:H7. There was more than 2.0 log CFU/g increase in E. coli O157:H7 populations on lettuce when held at 12 °C for 3 d, followed by additional growth during the remainder of the storage period. Although there was eventually a significant decline in visual quality of lettuce held at 12 °C, the quality of this lettuce was still fully acceptable when E. coli O157:H7 growth reached a statistically significant level. Therefore, maintaining fresh-cut products at 5 °C or below is critical for reducing the food safety risks as E. coli O157:H7 grows at a rapid, temperature-dependent rate prior to significant quality deterioration. Practical Application:, Specific information regarding the effect of temperature on pathogen growth on leafy greens is needed to develop science-based food safety guidelines and practices by the regulatory agencies and produce industry. Temperature control is commonly thought to promote quality of leafy greens, not safety, based at least partially on a theory that product quality deterioration precedes pathogen growth at elevated temperatures. This prevalent attitude results in temperature abuse incidents being frequently overlooked in the supply chain. This study demonstrates that human pathogens, such as E. coli O157:H7, can grow significantly on commercially packaged lettuce salads while the product's visual quality is fully acceptable. Packaged fresh-cut salads are marketed as "ready-to-eat" while lacking an effective pathogen kill step during their preparation. Thus, maintaining storage temperature at 5 °C or below is critical to prevent pathogen proliferation and mitigate food safety risks should pathogen contamination inadvertently occur during crop growth or postharvest fresh-cut processing. [source] Recent advances in extending the shelf life of fresh Agaricus mushrooms: a reviewJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2010Preeti Singh Abstract Postharvest browning of Agaricus mushrooms is a severe problem that reduces the shelf life of harvested mushrooms because of their continued respiration and biochemical activity. There are no simple answers and no single treatment is known to limit overall quality deterioration. However, there are several strategies that are being implemented in order to reduce the rate of respiration for mushrooms. Packaging technology is the common denominator that allows us to implement these strategies and thus is key to quality preservation. In this review, first, the major factors involved in postharvest quality deterioration are discussed and then technological advances/methods used to counteract these hurdles are presented. Copyright © 2010 Society of Chemical Industry [source] Soil moisture stress-induced alterations in bioconstituents determining tea qualityJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2003PR Jeyaramraja Abstract The impact of water stress on the biochemical constituents that determine black tea quality was investigated. Phenylalanine ammonia lyase (PAL) activity was highest in the drought tolerant ,Assam' cultivar UPASI-2, followed by UPASI-8 and UPASI-9, under non-stress conditions. Under soil moisture stress a reduction in PAL activity was found in all three clones investigated. A strong positive correlation was observed between an increase in soil moisture deficit and a decrease in PAL activity. Lower PAL activity correlated well with lower synthesis of flavanols such as epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), which are important precursors of theaflavin-3,3,-digallate that determines final tea quality. Altered synthesis of EGCG and ECG could be due to their molecular rearrangement at elevated leaf temperature during drought. Synthesis of quality constituents such as gallic acid and caffeine declined significantly owing to both drought and waterlogging stress. The reduction in gallic acid due to water stress could lead to lower synthesis of theaflavin fractions such as epitheaflavic acid, epitheaflavic acid-3,-gallate and theaflavic acid and, thereby, quality deterioration. Similarly to drought, flooding stress was also found to alter the biochemical constituents necessary for tea quality. Copyright © 2003 Society of Chemical Industry [source] Seasonal and diel changes of dissolved oxygen in a hypertrophic prairie lakeLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 3 2005Richard D. Robarts Abstract Humboldt Lake, a hypertrophic prairie lake typical of many found on the Great Plains of North America, is usually ice-covered from early November to about mid-May. The lake is an important recreational fishery, now mainly stocked with walleye. It has a high potential risk of experiencing fish kills because of the very large cyanobacterial blooms that develop in it, the high rates of algal and bacterial production and the high concentrations of ammonia (NH3 -N) and dissolved organic matter. Following the collapse of cyanobacterial blooms, shallow prairie lakes are known to undergo periods of anoxia that can lead to summer fish kills. In some of the lakes, anoxia forms during the long period of ice cover, causing winter fish kills. Two years of seasonal and diel data (total phosphorus, dissolved oxygen (DO), NH3 -N and chlorophyll- a concentrations, and bacterial production) were analysed in this study to assess why significant fish kills did not occur during this period or during the , 30 years of records from Saskatchewan Environment. Humboldt Lake did not become anaerobic, either following the collapse of the cyanobacterial bloom or under ice cover, indicating that the oxygen (O2) influx (strong mixing) and production processes were greater than the microbial and chemical O2 demands, both over seasonal and diel time scales. Several published risk threshold criteria to predict the probability of summer and/or winter fish kills were applied in this study. The threshold criteria of maximum summer chlorophyll and maximum winter NH3 -N concentrations indicated that a summer fish kill was unlikely to occur in this hypertrophic prairie lake, provided its water quality remained similar to that during this study. Similarly, the threshold criteria of initial DO storage before ice cover and the rate of O2 depletion under ice cover also indicated a winter fish kill was unlikely. However, recent development in the watershed might have resulted in significant water quality deterioration and the winter fish kill that occurred in 2005. [source] A discussion on the performance of impedance matched antenna system and considerations for a better performanceMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2008Adnan Kaya Abstract Impedance matching networks are used extensively in radio communications. In this study, ,-matching circuit has been used as a matching network. The return loss level of several impedance matched microstrip antennas are compared as a function of matching techniques. The ,-matching device is used to construct the antenna tuning units, which is only used to match the front module and the antenna. This circuit impedance region has been investigated analytically under the variable load condition. When the mismatch is occurred, the result is an increase in the energy consumption or transmission quality deterioration. In addition, the input module in antenna system could be damaged if reflection of the signal levels is excessively high. This is interesting application because antennas cannot be considered alone as component with changing electromagnetic properties. The rectangular microstrip antenna was designed at 2.5 GHz frequency by using microstrip feed line. Better return loss level which is ,16.86 dB has been obtained for this antenna using ,-matching circuit. It is shown that theoretical, simulation, and laboratory results are good agreement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 410,415, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23101 [source] Growth and characterization of ZnMgTe/ZnTe layered structures grown by molecular beam epitaxyPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2010S. Imada Abstract ZnMgTe/ZnTe layered structures were grown on ZnTe substrates by molecular beam epitaxy, and the crystal structures were characterized using X-ray diffraction methods. This structure would be the waveguide for various optoelectronic devices. Therefore, the crystal quality of this layered structure would be very crucial for the realization of high performance devices. ZnMgTe is lattice mismatched to ZnTe, and the increase of the ZnMgTe layer thickness or Mg mole fraction ratio would result in the crystal quality deterioration of the layered structure. The critical layer thickness (CLT) was theoretically derived, and various structures with various ZnMgTe layer thickness and Mg mole fraction were grown. The lattice mismatch strain relief and crystal quality of those samples were investigated by means of X-ray reciprocal space mapping (RSM) and cross sectional transmission electron microscopy (TEM). The dislocation formation and the lattice mismatch relaxation were confirmed for various samples and it was revealed that the calculated CLT values could be used as an appropriate guideline to design the dislocation free and high performance device structures (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Initial influence of fertilizer nitrogen types on water qualityAQUACULTURE RESEARCH, Issue 7 2010Charles C Mischke Abstract Using different sources of nitrogen as fertilizers in nursery ponds may affect water quality and plankton responses. We evaluated water quality variables and plankton population responses when using different nitrogen sources for catfish nursery pond fertilization. We compared calcium nitrate (12% N), sodium nitrite (20% N), ammonium chloride (26% N), ammonium nitrate (34% N) and urea (45% N) in 190-L microcosms at equimolar nitrogen application rates. Sodium nitrite-fertilized microcosms had higher nitrite and nitrate levels during the first week; no other differences in the water quality were detected among fertilizer types (P>0.05). No differences in green algae, diatoms or cyanobacteria were detected among treatments; desirable zooplankton for catfish culture was increased in urea-fertilized microcosms. Based on these results, any form of nitrogen used for pond fertilization should perform similarly without causing substantial water quality deterioration. Ammonium nitrate and urea contain a higher percentage of nitrogen, requiring less volume to achieve dosing levels. If both urea and ammonium nitrate are available, we recommend using the one with the least cost per unit of nitrogen. If both types of fertilizer have an equal cost per unit of nitrogen, we recommend using urea because of the potential advantage of increasing desirable zooplankton concentrations. [source] Use of Volatiles as Indicators of Lipid Oxidation in Muscle FoodsCOMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, Issue 1 2006Carolyn F. Ross ABSTRACT Lipid oxidation has long been recognized as a leading cause of quality deterioration in muscle foods and is often the decisive factor in determining food product storage life. Lipid oxidation generates a number of products, including volatile compounds, which are the major contributors to the development of rancid off-flavors and odors. Over the years, methodologies have been developed to quantify lipid oxidation products in muscle foods. This article reviews the analytical methods that have been used to quantify volatile compounds as indicators of lipid oxidation in muscle foods. The sampling methodologies of distillation/solvent extraction and headspace analysis, and isolation methods associated with gas chromatographic (GC) and high-performance liquid chromatography (HPLC) analyses are discussed. Within gas chromatographic methodologies, headspace (HS) sampling (static HS, dynamic purge-and-trap HS techniques, and solid-phase microextraction [SPME]) are addressed. [source] | |||||||||||||||||||