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Prolonged Storage (prolonged + storage)
Selected AbstractsColor Stability of Edible Coatings During Prolonged StorageJOURNAL OF FOOD SCIENCE, Issue 7 2000T.A. Trezza ABSTRACT: The yellowing rates of edible coatings were determined at 23, 40, and 55 °C at 75% relative humidity (RH). Whey protein isolate (WPI) coatings had lower yellowing rates than whey protein concentrate (WPC) and the same rates as shellac coatings. Hydroxypropyl methylcellulose (HPMC) coatings had the lowest yellowing rates. Zein coatings became less yellow during storage; however, their color was still pronounced. Activation energies and Q10 values for the yellowing of whey protein coatings were similar to those previously reported for the browning of whey powder. The results indicate that WPI coatings can be used in place of shellac coatings when low-color development is desired. WPC coatings can be used to tailor color development of a food. [source] Diagnostic effects of prolonged storage on fresh effusion samples,,DIAGNOSTIC CYTOPATHOLOGY, Issue 1 2007Frances Manosca M.D. Abstract The effects on morphology and diagnostic interpretation of delayed processing of refrigerated effusion samples have not been well documented. The potential for cellular degeneration has led many laboratories to reflexively fix samples rather than submit fresh/refrigerated samples for cytologic examination. We sought to determine if effusion specimens are suitable for morphologic, immunocytochemical, and DNA-based molecular studies after prolonged periods of refrigerated storage time. Ten fresh effusion specimens were refrigerated at 4°C; aliquots were processed at specific points in time (days 0, 3, 5, 7, 10, 14). Specimens evaluated included four pleural (3 benign, 1 breast adenocarcinoma) and six peritoneal (2 ovarian adenocarcinomas, 1 malignant melanoma, 2 mesotheliomas, 1 atypical mesothelial) effusions. The morphology of the cytologic preparations from the 10 effusions was preserved and interpretable after 14 days of storage at 4°C. The immunocytochemical profile of the samples (AE1/AE3, EMA, calretinin, and LCA) was consistent from day 0 to day 14. Amplifiable DNA was present in all samples tested on day 14. We conclude that cytopathologic interpretation of effusion samples remains reliable with refrigeration at 4°C even if processing is delayed. Diagn. Cytopathol. 2007;35:6,11. © 2006 Wiley-Liss, Inc. [source] Evaluation of Thin Film Titanium Nitride Electrodes for Electroanalytical ApplicationsELECTROANALYSIS, Issue 10 2007Carolina Nunes, Kirchner Abstract Titanium nitride is a hard and inert conducting material that has yet not been widely used as electrode material for electroanalytical applications although there are highly developed protocols available to produce well adherent micro and nanostructured electrodes. In this paper the possibilities of using titanium nitride thin films for electroanalytical applications is investigated. Scanning electrochemical microscope (SECM) was used for analysis of the redox kinetics of a selected fast redox couple at thin films of titanium nitride (TiN) in different thicknesses. The investigation was carried out by approaching an amperometric ultramicroelectrode (UME) to the TiN film while the soluble redox couple (ferrocenemethanol/ferrociniummethanol) served as mediator in a SECM configuration. The substrate was biased at a potential so that it rereduces the species being produced at the UME, thus controlling the feedback effect. Normalized current,distance curves were fitted to the theoretical model in order to find the apparent heterogeneous standard rate constant (k°) at the sample. The data are further supported by structural investigation of the TiN films using scanning force microscopy and X-ray photoelectron spectroscopy. It was found that the kinetics are little influenced by prolonged storage in air. The heterogeneous standard rate constants in 2,mM ferrocenemethanol were (0.73±0.05)×10,3,cm s,1 for 20,nm TiN thin layer, (1.5±0.2)×10,3,cm s,1 for 100,nm TiN thin layer and (1.3±0.2)×10,3,cm s,1 for 300,nm TiN thin layer after prolonged storage in air. Oxidative surface treatment (in order to remove organic adsorbates) decreased the kinetics in agreement with a thicker oxide layer on the material. The results suggest that their direct use for amperometric detection of reversible redox systems in particular at miniaturized configurations may be advantageous. [source] Storage-associated artefact in equine muscle biopsy samplesEQUINE VETERINARY JOURNAL, Issue 1 2009R. L. Stanley Summary Reasons for performing study: Muscle biopsy is increasingly used in equine veterinary practice for investigating exertional, inflammatory or immune mediated myopathies and unexplained muscle atrophy. Although formalin-fixed samples are often used, for complete evaluation, fresh-frozen tissue is required. Freezing muscle in veterinary practice is impractical: samples sent to specialist laboratories for processing are therefore susceptible to delays, potentially leading to artefact and compromising histological interpretation. Hypothesis: Altered temperature, duration and hydration status influence the severity of storage-induced artefact in equine muscle. Methods: Skeletal muscle obtained immediately post euthanasia was divided into 6 independent samples from each of 8 horses. One sample per horse was frozen immediately in isopentane precooled in liquid nitrogen. Additional samples were stored in conditions designed to mimic possible situations encountered in practice, including increased storage times, temperature and hydration status. Following storage, stored samples were frozen as before. Cryosections were stained using haematoxylin and eosin and ranked for artefact on 2 occasions by 2 blinded observers. The best samples were processed subsequently with a panel of routine stains and immunolabelled for collagen V to enable the measurement of minimum fibre diameters. Results: Both prolonged storage and increased hydration resulted in more storage-associated artefact. Samples stored for 24 h chilled on dry gauze were ranked higher than those stored on damp gauze; however, a panel of routinely-used histochemical staining techniques was unaffected by chilled 24 h storage. There was no significant effect of storage on mean fibre diameter; however, both chilled dry and damp storage for 24 h caused a significant increase in fibre-size variability. Conclusion and potential relevance: Caution should be exercised when interpreting fibre size profiles in shipped samples. Equine muscle biopsy samples are optimally shipped in dry gauze, sealed in plastic containers and shipped on ice packs to be processed within 24 h and can thus be interpreted by the receiving laboratory with minimal artefact. [source] EFFECT OF PACKAGING AND STORAGE TIME ON BEEF QUALITATIVE AND MICROBIAL TRAITSJOURNAL OF FOOD QUALITY, Issue 2010MARIA D'AGATA ABSTRACT The effect of polyvinyl chloride packaging (PP), vacuum packaging (VP) and modified atmosphere packaging (MAP) (60% O2, 30% CO2, 10% N2) on some quality parameters and microbiological profile of beef was studied. Longissimus dorsi samples were examined at 7-day intervals during storage at 4C ± 2C, until 21 days. pH of PP beef increased during storage, whereas in VP and MAP beef remained stable. Superficial color darkened for PP samples, remaining stable until 7 and 21 days for VP and MAP samples, respectively; internal color was not significantly influenced by either storage time and packaging methods. Water-holding capacity was not affected by packaging methods, increasing from 7 to 21 days. VP showed lower lipid oxidation than MAP until 21 days and than PP until 14 days. Total mesophilic counts reached the threshold of 107 ufc/g after 7 days in PP and after 14 and 21 days in MAP and VP, respectively. PRACTICAL APPLICATIONS The results of this study confirmed that meat packaged in polyvinyl chloride packaging (PP) must be stored for few days to not fall into pH, color and microbiological alterations; meat packaged in modified atmosphere packaging (MAP), even though maintained appreciable superficial colorimetric characteristics, showed a high microbiological growth from 14 days of storage; meat vacuum packaged (VP), although the worst colorimetric appearance, showed the best keeping properties in terms of microbiological profile and lipid oxidation lower than MAP until 21 days of storage. Nevertheless, the fact that the internal color of meat is similar among different packaging systems, independently from time of storage, may suggest that VP system may be useful for prolonged storage of big pieces of meat. [source] Chemical and nutritional quality of silage made from raw or cooked lizard fish (Saurida undosquamis) and blue crab (Portunus pelagicus)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2009Diep TN Mach Abstract Twelve silages were prepared from uncooked or cooked lizard fish (Saurida undosquamis) and blue crab (Portunus pelagicus) and stored at ambient temperature (30 ± 2 °C) for 60 days. The antioxidative effect of adding ethoxyquin was also investigated. Generally, the nutritional quality of all the silages was stable for up to 60 days of storage and the composition of raw materials was reflected in the composition of the silages. Crab had a lower level of crude protein than fish (85 versus 162 mg kg,1), but a higher level of ash (96 versus 36 g kg,1); moreover, there were significant differences in nutritional composition between uncooked and cooked materials. High level of ash in crab required addition of high levels of formic acid in crab-related silages. At the end of the experiment cooked silages showed a tendency for spoilage; in particular, maggots were observed in cooked crab silages on the last few days of the experiment. Comparison of treatments with or without ethoxyquin showed that only rancidity of fish silage groups was higher without addition of ethoxyquin. Uncooked materials are more suitable for prolonged storage than cooked materials, and it is probably not necessary to add antioxidants to silages made from material with low lipid content. Copyright © 2009 Society of Chemical Industry [source] Effect of lyophilisation, refrigerated storage and frozen storage on the coagulant activity and microbiological quality of Cynara cardunculus L. extractsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2008Luis Tejada Abstract BACKGROUND:Cheese-makers have traditionally kept vegetable coagulants refrigerated until use, even though little was known of their microbiological quality or coagulant activity during storage. This study aimed to assess the efficacy of lyophilisation, refrigerated storage and frozen storage of fresh vegetable extract as a means of standardising coagulant activity in terms of coagulation times, pH and microbiological quality. RESULTS:Neither the pH nor the coagulation time of lyophilised extracts was significantly modified during 1 year; however, changes were observed following frozen storage, and more notable following refrigerated storage. Lyophilisation of aqueous extracts prompted the destruction of most micro-organisms; low counts initially noted for total mesophiles, lactic acid bacteria and yeasts disappeared during the first few days of storage, due to low water activity. There was a generalised decrease in micro-organism counts during frozen storage. Refrigeration was found to be unsuitable for storing of cardoon extract; an increase of roughly 2 log unit counts was recorded in total mesophile, lactic acid bacteria, yeast and mould counts after 1 year of refrigerated storage. CONCLUSION:Refrigerated storage cannot be considered a suitable method for prolonged conservation of aqueous cardoon extract. Both lyophilisation and frozen storage of aqueous extracts proved ideal for prolonged storage of vegetable coagulant. Lyophilisation additionally had certain advantages over frozen storage. Copyright © 2008 Society of Chemical Industry [source] Effect of processing and storage time on in vitro digestibility and resistant starch content of two bean (Phaseolus vulgaris L) varietiesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2003Perla Osorio-Díaz Abstract Seeds from two commercial bean varieties were cooked and stored for different times and analysed for chemical composition and in vitro starch digestibility. Parallel portions of cooked seeds were dried at 55 °C, milled and stored as flours. In general, protein and ash contents in both samples did not change with storage time, but statistical differences were shown between the two varieties (p < 0.05). Available starch (AS) contents in flours from the ,negro' variety did not change (p < 0.05) with storage time and, in general, were higher than in ,flor de mayo' samples, whose AS levels decreased during storage. The lower AS in ,flor de mayo' flour could be the consequence of formation of resistant starch due to retrogradation. Samples of whole ,negro' seeds did not show differences in AS content at 0, 24 and 48 h of storage compared with the corresponding flours, but at 72 and 96 h the AS increased in the whole samples. ,Flor de mayo' showed a similar pattern in flour and whole samples, with slightly higher values in the whole seeds. In general, total resistant starch (RS) content in the two varieties was higher in the flours than in ,whole' seeds, a fact that is not easy to explain at present. ,Negro' flour presented an RS content around 65.0 g kg,1, and approximately 55.0 g kg,1 was recorded in ,flor de mayo', with slight changes when storage time increased. Whole ,flor de mayo' showed significant levels of the retrograded portion of resistant starch (RRS), which did not change with storage time (p < 0.05). However, values were lower than in the flours. A pattern similar to that of the ,negro' variety was obtained for ,flor de mayo', since the flour exhibited higher amounts of RRS; however, in this variety, the RRS content in ,whole' samples decreased after prolonged storage. Flours presented higher amylolysis rates than whole samples, and the ease of digestion increased with storage time. Copyright © 2003 Society of Chemical Industry [source] Gene expression measurements in the context of epidemiological studiesALLERGY, Issue 12 2008C. Bieli Background:, Gene expression measurements became an attractive tool to assess biological responses in epidemiological studies. However, collection of blood samples poses various technical problems. We used gene expression data from two epidemiological studies to evaluate differences between sampling methods, comparability of two methods for measuring RNA levels and stability of RNA samples over time. Methods:, For the PARSIFAL study, PBLC of 1155 children were collected using EDTA tubes in two countries. In the PASTURE study, tubes containing RNA-stabilizing solutions (PAXgene® Blood RNA Tubes; PreAnalytiX) were used to collect cord blood leucocytes of 982 children in five countries. Real-time PCR (conventional single tube assay and high-throughput low density arrays) was used to quantify expression of various innate immunity genes. In 77 PARSIFAL samples, gene expression was measured repeatedly during prolonged storage. Results:, In PARSIFAL (EDTA tubes) the median RNA yield after extraction significantly differed between the two centres (70 and 34 ng/,l). Collecting blood into an RNA-stabilizing solution markedly reduced differences in RNA yield in PASTURE (range of medians 91,107 ng/,l). The agreement [Spearman rank correlation (r)] between repeated measurements of gene expression decreased with increasing storage time [e.g., for CD14: r (first/second measurement) = 0.35; r (first/third measurement) = 0.03]. RNA levels measured with either the conventional method or low-density arrays were comparable (r > 0.9). Conclusion:, Collecting blood samples into tubes containing an RNA-stabilizing solution increases RNA yield and reduces its variability. Long-term storage of samples may lead to RNA degradation, requiring special attention in longitudinal studies. [source] Roles of antioxidants on prolonged storage of avian spermatozoa in vivo and in vitroMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 3 2003Christelle Bréque Abstract This review focuses on natural and assisted prevention against lipid peroxidation in avian spermatozoa. The presence of high levels of n-6 polyunsaturated fatty acids (PUFAs) in the plasma membrane creates favorable conditions for the formation of peroxidative products, a major cause of membrane damage which may ultimately impair male fertility. However, a complex antioxidant system involving vitamin C, vitamin E and GSH is naturally present in avian semen. Coupled with a battery of enzymatic defenses (e.g., SOD, GSH-Px either Se- or non-Se-dependent), this system acts to prevent or restrict the formation and propagation of peroxides. The presence of specialized sites dedicated to prolonged sperm storage in avian females raises the question of durable protection of sperm membranes against peroxidation. Preliminary observations have revealed the presence of a specific antioxidant system at these sites in which vitamin C could exert a major role. From a practical standpoint, the extensive use of artificial insemination in poultry, along with the emergence in some species of workable techniques to cryopreserve spermatozoa, demand better control of peroxidation occurring in the plasma membrane of spermatozoa before or during storage. Dietary supplementation with vitamin E is effective in limiting lipid peroxidation of sperm plasma membranes, both in chickens and turkeys. In addition, organic Se with or without vitamin E stimulates Se-GSH-Px activity in seminal plasma. Preliminary observations in female chickens have also revealed the effectiveness of dietary supplementation with vitamin E, organic selenium or both to sustain fertility in aging flocks. Mol. Reprod. Dev. 66: 314,323, 2003. © 2003 Wiley-Liss, Inc. [source] Comparative analysis of neonicotinoid binding to insect membranes: II.PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 10 2004An unusual high affinity site for [3H]thiamethoxam in Myzus persicae, Aphis craccivora Abstract Neonicotinoids represent a class of insect-selective ligands of nicotinic acetylcholine receptors. Imidacloprid, the first commercially used neonicotinoid insecticide, has been studied on neuronal preparations from many insects to date. Here we report first intrinsic binding data of thiamethoxam, using membranes from Myzus persicae Sulzer and Aphis craccivora Koch. In both aphids, specific binding of [3H]thiamethoxam was sensitive to temperature, while the absolute level of non-specific binding was not affected. In M persicae, binding capacity (Bmax) for [3H]thiamethoxam was ca 450 fmol mg,1 of protein at 22 °C and ca 700 fmol mg,1 of protein at 2 °C. The negative effect of increased temperature was reversible and hence not due to some destructive process. The affinity for [3H]thiamethoxam was less affected by temperature: Kd was ca 11 nM at 2 °C and ca 15 nM at 22 °C. The membranes also lost binding sites for [3H]thiamethoxam during prolonged storage at room temperature, and upon freezing and thawing. In A craccivora, [3H]thiamethoxam was bound with a capacity of ca 1000 fmol mg,1 protein and an affinity of ca 90 nM, as measured at 2 °C. Overall, the in vitro temperature sensitivity of [3H]thiamethoxam binding was in obvious contrast to the behaviour of [3H]imidacloprid studied in parallel. Moreover, the binding of [3H]thiamethoxam was inhibited by imidacloprid in a non-competitive mode, as shown with M persicae. In our view, these differences demonstrate that thiamethoxam and imidacloprid, which represent different structural sub-classes of neonicotinoids, do not share the same binding site or mode. This holds also for other neonicotinoids, as we report in a companion article. Copyright © 2004 Society of Chemical Industry [source] An Investigation of Composite Propellant Accelerated Ageing Mechanisms and KineticsPROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 3 2003Michael Abstract The ageing kinetics and mechanisms of a composite solid rocket propellant were investigated by monitoring unstressed propellant samples during prolonged storage at elevated temperatures. For samples confined under air during ageing, it was determined that oxidative cross-linking of the propellant binder was the main degradation mechanism over time. Plasticizer loss was a significant ageing mechanism only for those samples aged unconfined. In addition, there was an indication that ambient humidity had a significant but reversible effect on propellant mechanical properties. Arrhenius mathematical relationships were derived in order to ascertain the extent to which ageing was accelerated by increased propellant temperature. An activation energy for binder oxidation of between 71 and 74,kJ/mol was determined. [source] | |||||||||||||