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Various Additives (various + additive)
Selected AbstractsBench-scale evaluation of in situ bioremediation strategies for soil at a former manufactured gas plant siteENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2005Jun Li Abstract We examined the biodegradation and desorption of a set of 15 polycyclic aromatic hydrocarbon (PAH) compounds in coal tar,contaminated soil at a former manufactured gas plant site to evaluate the feasibility of in situ bioremediation. Experiments were conducted in well-mixed aerobic soil suspensions containing various additives over a 93- to 106-d period. In general, both biotransformation and desorption decreased with PAH ring size, becoming negligible for the six-ring PAH compounds. Biodegradation by indigenous microorganisms was strongly accelerated by addition of inorganic nutrients (N, P, K, and trace metals). The rates of biotransformation of PAH compounds by indigenous microorganisms in nutrient-amended flasks outpaced their maximum (i.e., chelate-enhanced) rates of desorption to an infinite sink (Tenax®) in sterilized systems run in parallel, suggesting that indigenous organisms facilitated desorption. Biodegradation by indigenous organisms in nutrient-amended flasks appeared to be unaffected by the addition of a site-derived bacterial enrichment culture, resulting in approximately 100-fold higher aromatic dioxygenase levels, and by the addition of 0.01 M chelating agent (citrate or pyrophosphate), although such chelating agents greatly enhanced desorption in microbially inactivated flasks. The strong ability of nutrients to enhance degradation of the bioavailable PAHs indicates that their persistence for many decades at this site likely results from nutrient-limited natural biodegradation, and it also suggests that an effective strategy for their bioremediation could consist simply of adding inorganic nutrients. [source] Cold flow properties of fuel mixtures containing biodiesel derived from animal fatty wasteEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 9 2006Kiril Kazancev Abstract The aims of the present study were to evaluate the cold temperature behavior of methyl esters of vegetable and animal origin and of their mixtures with fossil diesel fuel, as well as to investigate the effectiveness of different depressants. Various blends of rapeseed oil methyl esters, linseed oil methyl esters, pork lard methyl esters and fossil diesel fuel were prepared, and both cloud point and cold filter plugging point (CFPP) were analyzed. It was found that mixtures with CFPP values of ,5,°C and lower may contain up to 25% of pork lard methyl esters; whereas the ratio of summer fossil diesel fuel and rapeseed oil methyl esters may vary over a wide range, i.e. such mixtures can be used in a diesel engine in the summer. In the transitory periods it is possible to use up to 20% animal and vegetable ester blends (3,:,7) with winter fossil diesel, whereas only up to 5% of esters can be added to the fuel used in winter. In order to improve the cold properties of rapeseed oil, pork lard and linseed oil methyl ester mixtures, various additives were tested. Depressant Viscoplex 10,35 with an optimal dose of 5000,mg/kg was found to be the most effective. [source] The use of probiotics in shrimp aquacultureFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2006Ali Farzanfar Abstract Shrimp aquaculture, as well as other industries, constantly requires new techniques in order to increase production yield. Modern technologies and other sciences such as biotechnology and microbiology are important tools that could lead to a higher quality and greater quantity of products. Feeding and new practices in farming usually play an important role in aquaculture, and the addition of various additives to a balanced feed formula to achieve better growth is a common practice of many fish and shrimp feed manufacturers and farmers. Probiotics, as ,bio-friendly agents' such as lactic acid bacteria and Bacillus spp., can be introduced into the culture environment to control and compete with pathogenic bacteria as well as to promote the growth of the cultured organisms. In addition, probiotics are nonpathogenic and nontoxic microorganisms without undesirable side-effects when administered to aquatic organisms. These strains of bacteria have many other positive effects, which are described in this article. [source] EFFECTS OF COOKED TEMPERATURES AND ADDITION OF ANTIOXIDANTS ON FORMATION OF HETEROCYCLIC AROMATIC AMINES IN PORK FLOSSJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2009GUOZHOU LIAO ABSTRACT Heterocyclic aromatic amines (HAAs) are an important class of food mutagens and carcinogens produced in meats cooked at high temperature. The formation of HAAs in pork floss during processing and the effect of vitamin C and vitamin E on HAAs formation in pork floss were studied. Pork floss was prepared by steaming of raw pork, followed by pressing, tearing, adding various additives, and then the cooked pork was subjected to stir frying. The various HAAs in pork floss were isolated by solid phase extraction and analyzed by high-performance liquid chromatography (HPLC). Results showed that the type and level of HAAs increased with increasing processing temperature. Up to seven HAAs, 9H-pyrido[4,3-b]indole (Norharman), 1-methyl-9H-pyrido[4,3-b]indole (Harman), 2-amino-1- methyl-6-phenylimidazo[4,5-f]pyridine (PhIP), 2-amino-dipyrido[1,2-a: 3,,2,-d]imidazole (Glu-P-2), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-9H-pyrido[2,3-b]indole (AaC) and 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAaC) were detected in pork floss when stir fried at 150C. Color development increased with cooking temperatures, and was correlated with HAAs formation. The addition of vitamin C at various levels was not effective toward HAAs inhibition. However, the incorporation of 0.1% vitamin E reduced Norharman, PhIP, AaC and MeAaC concentrations in the pork floss. PRACTICAL APPLICATION The formation of heterocyclic aromatic amines (HAAs) is one of the most unfavorable changes during the cooking of food. Since the connection between the consumption of dietary carcinogens and cancer risks in human has been established, interest in this matter has been growing. However, the processing methods and conditions of Chinese traditional food are different from Western, and to date, little is known about HAAs content in the traditional meat products of China. The information derived from this study serves as an essential base of knowledge from a public health standpoint, and contributes to a repository of HAAs information relevant to Chinese cooking; it also can provide clues to understanding the factors that affect HAAs formation and can indicate means of reducing or eliminating these compounds. [source] INHIBITION OF STALING IN CHAPATI (INDIAN UNLEAVENED FLAT BREAD)JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2008IRSHAD M. SHAIKH ABSTRACT Chapati is an unleavened Indian flat bread made from whole wheat flour usually consumed immediately after preparation as it becomes hard on keeping because of staling. Large-scale mechanized preparation of ready-to-eat chapatis will have to address this problem. Investigations were made to study the effect of sodium stearoyl-2-lactylate (SSL), glycerol monostearate, propylene glycol, sorbitol, ,-amylase, xylanase, maltodextrin and guar gum when added to chapati dough, on the inhibition of staling in chapatis stored at 29 ± 1C and 4 ± 1C. Chapatis were prepared from whole wheat flour dough containing (salt, 5% oil, appropriate preservatives and the aforementioned additives. Chapatis were packed in self-sealing low-density polyethylene bags and were stored for 10 days at 29 ± 1C and 4 ± 1C. Stored chapatis were analyzed for various staling parameters such as moisture content, texture, water-soluble starch, in vitro enzyme digestibility, enthalpy change (,H) and sensory quality. Staling of chapatis at 29 ± 1C and at 4 ± 1C of storage was inhibited by all additives to different extents; the extent of staling was less at 4 ± 1C. Maltodextrin at 0.3% (w/w) was found to be the most effective. Several combinations of additives were also studied, and the best combination was (100 ppm) + SSL (0.375%) levels. PRACTICAL APPLICATIONS Chapati, a traditional staple food of Indians, is unleavened flat bread made from whole wheat flour. With rapidly changing lifestyles, changing socio-economic trends and increasing urbanization and consumerism there is a rising demand for convenience foods which require minimum or no preparation time particularly the ready-to-eat (RTE) type of foods. Chapatis are generally baked fresh twice a day for lunch and dinner, and unless eaten immediately after baking, these stale rapidly and become difficult to chew. The most important parameter of chapati quality is its texture. The texture is generally evaluated in terms of tenderness, flexibility and its suitability to be folded into a spoon shape for eating with curried preparation. RTE chapatis are the latest addition to the species of "convenience foods." Keeping this in mind the research was undertaken to improve quality of chapati with the addition of various additives and improvements for the inhibition of staling in chapati. [source] Water sorption, glass transition, and protein-stabilizing behavior of an amorphous sucrose matrix combined with various materialsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2010Koreyoshi Imamura Abstract The effects of various additives on the physical properties of an amorphous sugar matrix were compared. Amorphous, sugar,additive mixtures were prepared by freeze-drying and then rehumidified at given RHs. Sucrose and eighteen types of substances were used as the sugar and the additive, respectively, and water sorption, glass-to-rubber transition, and protein stabilization during freeze-drying for the various sucrose,additive mixtures were examined. The additives were categorized into two groups according to their effects on Tg and water sorption. Presence of polysaccharides, cyclodextrins, and polymers (large-sized additives) resulted in a decrease in equilibrium water content from the ideal value calculated from individual water contents for sucrose and additive, and in contrast, low MW substances containing ionizable groups (small-ionized additives) resulted in an increase. The increase in Tg by the addition of large-sized additives was significant at the additive contents >50,wt.% whereas the Tg was markedly increased in the lower additive content by the addition of small-ionized additives. The addition of small-ionized additives enhanced the decrease in Tg with increasing water content. The protein stabilizing effect was decreased with increasing additive content in the cases of the both groups of the additives. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:4669,4677, 2010 [source] Radical clocks and electron transfer.JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 2005Comparison of crown ether effects on the reactivity of potassium, magnesium towards 1-bromo-2-(3-butenyl)benzene. Abstract The reaction of the title precursor of the aryl radical clock 1-bromo-2-(3-butenyl)benzene, 1Br, towards potassium and magnesium in THF was studied in the presence and absence of various additives, at ambient and low temperatures. The additives were cis -dicyclohexano-18-crown-6 or tert -butyl alcohol; the first one to render soluble potassium by forming its alkalide, the second to distinguish carbanionic from radical cyclization. The addition of 1Br to a THF stirred suspension of potassium pieces yields remarkably low amounts of products resulting from radical cyclization, in contrast to the amounts reported by Bunnett and Beckwith's group for the reaction in 67% ammonia,33% tert -butyl alcohol medium. The amount of cyclized products obtained with potassium pieces in THF is in the same range as that observed in the reaction of magnesium with 1Br in THF. This similarity allows us to discard the earlier triad hypothesis that we proposed to account for the unexpectedly low amounts of cyclized products of aryl halides radical clocks in Grignard reagent formation. The addition of crown ethers to the THF reaction medium induces contrasting effects for potassium and magnesium. A distinctive increase in the radical cyclization is observed for potassium, whereas the addition of crown inhibits the formation of Grignard reagent more efficiently when the solvent is diethyl ether than when it is THF. The observed effects are explained by putting in perspective the metal reactive dissolution with elementary steps occurring in the vicinity of a cathode. The reaction of potassium pieces or magnesium turnings is comparable to the heterogeneous electron transfer occurring at a cathode whereas the reaction of potassium in the presence of crown ether is comparable to homogeneous conditions of electron transfer obtained in redox catalysis. A discussion of the dianion hypothesis for the Grignard reaction of aryl halides is provided and the importance of considering the reactivity of reactive metal dissolution (or organic corrosion) in the framework of recent progress made in the modelling of electrode reactivity is emphasized. This paper shows that caution should be taken when radical clocks are used to study reactions at the metal,solution interface. More specifically, the non-observation of rearranged products from the radical clock (even for the very rapid ones) under these conditions does not necessary imply that there is no radical intermediate along the dominant reaction channel. This pattern of reactivity strongly contrasts with that usually observed when radical clocks are used in homogeneous media. The leading parameters in the rearranged/unrearranged products ratio seem to be the time that the reactive species (radical anions) created by the first electron transfer spend in the close vicinity of this surface, the rate constant of rearrangement of the radical formed by the cleavage of the radical anion and the redox properties of this radical. Copyright © 2005 John Wiley & Sons, Ltd. [source] Roles of additives in scratch resistance of high crystallinity polypropylene copolymersPOLYMER ENGINEERING & SCIENCE, Issue 1 2001C. Xiang Scratch behavior in neat and talc-filled high crystallinity polypropylene (PP) copolymers containing various additives is investigated using a cosntant load scratch test and two types of indentation tests (Rockwell and Shore D). The talcfilled PP copolymer exhibits high scratch visibilityand scratch depth. The addition of a nucleating agent or lubricant improves the scratch resistance of the talc-filled PP copolymer. Differential scanning calorimetry, scanning electron microscopy and attenuated total reflectance Fourier transform infrared spectroscopy are used to characterize crystallinity morphology and scratch mechanisms in PP systems. It is found that the scratch resistance of the PP copolymer systems investigated, in terms of scratch depth and scratch visibility, depends mainly on the fracture features generated during the scratch process. The influences of talc, nucleating agent and lubricant on the scratch behavior of PP are discussed. [source] | |||||||||||||