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Acetic Acid Solution (acetic + acid_solution)
Selected AbstractsDevelopment and Evaluation of an Ozonated Water System for Antimicrobial Treatment of Durum WheatJOURNAL OF FOOD SCIENCE, Issue 7 2009B. Dhillon ABSTRACT:, Ozonated water is reported to be effective in reducing the microbial load in foods such as fruits, vegetables, and grains. Ozonated water may be an effective alternative to chlorinated water in treating durum wheat before milling. Therefore, durum wheat was washed with ozonated water and analyzed for yeast and mold count (YMC) and aerobic plate count (APC). A system for producing and monitoring ozonated water was developed. The effect of water quality (tap, distilled, and ultra-pure), temperature (7, 15, and 25 °C), and pH (2, 4, and 6.5) was evaluated on the following: steady-state dissolved ozone concentration, ozone decay constant, half-life, mass transfer coefficient, equilibrium ozone concentration, and solubility ratio. The study of these parameters was important to attain a stable, high dissolved ozone concentration at the outset of washing and to have information for system improvement and scale-up. A 1% acetic acid solution (pH 2) at 15 °C resulted in high dissolved ozone concentration (21.8 mg/L) and long half-life (9.2 min). Subsequently, wheat was washed with 5 wash water types: distilled water, ozonated water (16.5 mg/L), chlorinated water (700 mg/L), acetic acid solution (1%), and acetic acid + ozonated water (1%, 20.5 mg/L). The treated samples were analyzed for YMC and APC. The acetic acid + ozonated water treatment was the most effective, with a reduction of 4.1 and 3.2 log10 colony forming units/g in YMC and APC, respectively. Though ozonated water was not very effective alone, it was useful in combination with acetic acid. [source] Modeling the Effect of Marination and Temperature on Salmonella Inactivation during Drying of Beef JerkyJOURNAL OF FOOD SCIENCE, Issue 4 2009Yohan Yoon ABSTRACT:, This study modeled the effect of drying temperature in combination with predrying marination treatments to inactivate Salmonella on beef jerky. Beef inside round slices were inoculated with Salmonella and treated with (1) nothing (C), (2) traditional marinade (M), or (3) dipped into a 5% acetic acid solution for 10 min before exposure to M (AM). After 24 h of marination at 4 °C, samples were dehydrated at 52, 57, or 63 °C. Total counts (tryptic soy agar supplemented with 0.1% sodium pyruvate, TSAP) and Salmonella (XLD agar) were enumerated after inoculation and at 0, 2, 4, 6, 8, and 10 h during drying. For calculation of death rates (DR, log CFU/cm2/h), shoulder period (h), low asymptote, and upper asymptote, cell counts from TSAP were fitted to the Baranyi model. The DRs were then further expressed as a function of storage temperature. Inactivation occurred without an initial lag phase (shoulder period), while correlation (R2) values of fitted curves were , 0.861. The DRs of C (,0.29 to ,0.62) and M (,0.36 to ,0.63) treatments were similar, while DRs of the AM treatment were higher (,1.22 to ,1.46). The DRs were then fitted to a polynomial equation as a function of temperature. After validation, good (C and M) or acceptable (AM) model performances were observed (R2= 0.954 to 0.987; bias factors: 1.03 [C], 1.01 [M], 0.71 [AM]; accuracy factors: 1.05 [C], 1.06 [M], 1.41 [AM]). The developed models may be useful in selecting drying temperatures and times in combination with predrying treatments for adequate inactivation of Salmonella in beef jerky. [source] Synthesis of 13C- and 14C-labelled catecholJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 7 2002Rong Ji Abstract 13C- and 14C-uniformly labelled catechol was synthesized from phenol in three steps. Phenol was derivatized with 2-chloro-5-nitrobenzophenone in THF containing NaH, followed by ortho -hydroxylation with 35% aqueous H2O2 in sulphuric acid/glacial acetic acid solution, and by cleavage with piperidine, giving an overall 80% yield with respect to phenol. Copyright © 2002 John Wiley & Sons, Ltd. [source] Near-critical carbon dioxide extraction and liquid chromatography determination of UV filters in solid cosmetic samples: A green analytical procedureJOURNAL OF SEPARATION SCIENCE, JSS, Issue 17 2005Amparo Salvador Abstract Near-critical carbon dioxide extraction of four UV filters used as sunscreens in lipsticks and makeup formulations is reported. Extraction parameters were optimized. Efficient recoveries were obtained after 15 min of dynamic extraction with a 80:20 CO2/ethanol mixture at 300 atm and 54°C, using a 1.8 mL/min flow rate. Extracts were collected in ethanol, and appropriately diluted with ethanol and 1% acetic acid to obtain a 70:30 v/v ethanol/1% acetic acid solution. The four UV filters were determined by LC with gradient elution using ethanol/1% acetic acid as mobile phase. The accuracy of the analytical procedure was estimated by comparing the results with those obtained by methods based on classical extraction. The proposed method only requires the use of CO2, ethanol and acetic acid avoiding the use of more toxic organic solvents, thus it could be considered as both operator and environment friendly. [source] Simultaneous determination of nicotinamide, pyridoxine hydrochloride, thiamine mononitrate and riboflavin in multivitamin with minerals tablets by reversed-phase ion-pair high performance liquid chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 8 2002Ke Li A reversed-phase ion-pair high performance liquid chromatographic method (HPLC) has been developed and validated for the routine analysis of nicotinamide, pyridoxine hydrochloride, thiamine mononitrate and riboflavin in multivitamin with minerals tablets. HPLC separation of the vitamins was performed on a Hypersil C18 column and detected by ultraviolet absorbance at 280,nm. The use of methanol-aqueous 0.5% acetic acid solution (18:82, v/v; containing 2.5,mM sodium hexanesulfonate, pH,=,2.8) as the mobile phase at a flow-rate of 1.2,mL/min enables the baseline separation of the four analytes free from interferences with isocratic elution at 30°C. The analysis time was 17,min per injection. The method was linear in the ranges of 5,90, 2.5,90, 5,95 and 25,450,µg/mL for thiamine mononitrate, riboflavin, pyridoxine hydrochloride and nicotinamide, respectively. The average coefficients of variation of within- and between-day assays were 2.2 and 3.6% for thiamine mononitrate, 1.8 and 2.4% for riboflavin, 1.3 and 1.7% for pyridoxine hydrochloride and 1.0 and 1.5% for nicotinamide, respectively. The average recoveries of thiamine mononitrate, riboflavin, pyridoxine hydrochloride and nicotinamide were 97.0, 97.2, 98.9 and 100.4% for the tablets, respectively. The method has been successfully applied to the simultaneous determination of nicotinamide, pyridoxine hydrochloride, thiamine mononitrate and riboflavin in multivitamin with minerals tablets. Copyright © 2002 John Wiley & Sons, Ltd. [source] EVALUATION OF CELLS OF LACTOBACILLUS DELBRUECKII SPP.JOURNAL OF FOOD QUALITY, Issue 6 20035 AND PEDIOCOCCUS ACIDILACTICI D3 SUSPENDED IN LACTIC OR ACETIC ACID AS BIOPRESERVATIVES ON FRESH CUT CANTALOUPE AT 7C, LACTIS RM A small although statistically significant (P < 0.05) inactivation of S. choleraesuis was observed when cantaloupe cubes were additionally inoculated with cells P. acidilactici suspended in 5.5 mM lactic acid or 5.5 mM glacial acetic acid solutions. However, the numbers of S. choleraesuis were not significantly lower than in the control on day 10. The amount of inactivation likely would have no practical importance. No significant decline in numbers of S. choleraesuis was attained when the cells of L. delbrueckii spp. lactis were suspended in 5.5 mM lactic acid. None of the treatments contributed to an effective (P > 0.05) inhibition of the spoilage flora on the melons. [source] The effect of high-pressure food processing on the sorption behaviour of selected packaging materialsPACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2004C. Caner Abstract The sorption behaviour and flavour-scalping potential of selected packaging films in contact with food simulant liquids (FSLs) (ethanol and acetic acid solutions) were evaluated after high-pressure processing (HPP). The films used were monolayer polypropylene (PP), a multilayer (polyethylene/nylon/ethylene vinyl alcohol/polyethylene: PE/nylon/EVOH/PE), film and a metallized (polyethylene terephthalate/ethylene,vinyl acetate/linear low-density polyethylene: metallized PET/EVA/LLDPE) material. D-limonene was used as the sorbate and was added to each of the FSLs. After HPP treatment at 800,MPa, 10,min, 60°C, the amount of D-limonene sorbed by the packaging materials and the amount remaining in the FSL was measured. Untreated controls (1,atm, 60°C and 40°C) were also prepared. Extraction of the D-limonene from the films was performed using a purge/trap method. D-limonene was quantified in both the films and the FSL, using gas chromatography (GC). The results showed that D-limonene concentration, in both the films and the food simulants, was not significantly affected by HPP, except for the metallized PET/EVA/LLDPE. Significant differences in D-limonene sorption were found in comparison with the control pouches. The results also showed that changes in temperature significantly affected the sorption behaviour of all films. Copyright © 2004 John Wiley & Sons, Ltd. [source] Development of a liquid extraction method and comparison with dynamic thermal stripping,thermal desorption (DTS,TD) method: sorption of D -limonene by flexible packaging filmsPACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2004Cengiz Caner Abstract The sorption of D -limonene into polymeric structures in contact with food simulant liquids (ethanol and acetic acid solutions) was determined using two methods, liquid extraction (LE) and dynamic thermal stripping,thermal desorption (DTS,TD). The polymeric films studied were PP (polypropylene), PE/nylon/EVOH/PE (polyethylene/nylon/ethylene vinyl alcohol/polyethylene) and metPET/VA EVA/LLDPE (metallized polyethylene terephthalate/ethylenevinyl acetate/linear low density polyethylene). Our assessment showed that both LE and DTS,TD techniques are valuable procedures. LE was evaluated as an alternative method with the advantage of being a simplified process. It was possible to measure the amount of D -limonene in the polymers using both methods. Correlation between methods was >82% and for the single layer polymers >92%. The respective sorption values obtained by the two methods were also found to be in good agreement. LE is simple and rapid to perform and, in general, gives slightly lower results compared to DTS,TS sorption tests conducted with adequate food simulants. The results indicate that the liquid extraction method is an excellent technique for the determination of sorbate concentration in polymeric structures. Copyright © 2004 John Wiley & Sons, Ltd. [source] Structural properties of trimers and tetramers of ribonuclease APROTEIN SCIENCE, Issue 10 2001Arianna Nenci Abstract Ribonuclease A aggregates (dimers, trimers, tetramers, pentamers) can be obtained by lyophilization from 40% acetic acid solutions. Each aggregate forms two conformational isomers distinguishable by different basic net charge. The crystal structure of the two dimers has recently been determined; the structure of the higher oligomers is unknown. The results of the study of the two trimeric and tetrameric conformers can be summarized as follows: (1) RNase A trimers and tetramers form by a 3D domain-swapping mechanism. N-terminal and C-terminal types of domain swapping could coexist; (2) the secondary structures of the trimeric and tetrameric conformers do not show significant differences if compared with the secondary structure of monomeric RNase A or its two dimers; (3) a different exposure of tyrosine residues indicates that in the aggregates they have different microenvironments; (4) the two trimeric and tetrameric conformers show different susceptibility to digestion by subtilisin; (5) dimers, trimers, and tetramers of RNase A show unwinding activity on double-helical poly(dA-dT) , poly(dA-dT), that increases as a function of the size of the oligomers; (6) the less basic conformers are more stable than the more basic ones, and a low concentration in solution of trimers and tetramers favors their stability, which is definitely increased by the interaction of the aggregates with poly(dA-dT) , poly(dA-dT); (7) the products of thermal dissociation of the two trimers indicate that their structures co ld be remarkably different. The dissociation products of the two tetramers allow the proposal of two models for their putative structures. [source] ChemInform Abstract: Synthesis and Characterization of La1+xSr2-xCoMnO7-, (x = 0.02; , = 0.1).CHEMINFORM, Issue 36 2010H. El Shinawi Abstract The n = 2 Ruddlesden,Popper phases LaSr2CoMnO7 and La1.2Sr1.8CoMnO7 are prepared by a sol,gel method from acetic acid solutions of stoichiometric amounts of La2O3, SrCO3, Co(OAc)2, and Mn(OAc)2 (calcination in flowing oxygen at 1350 °C, 18 h). [source] Mild oxidative cyclization of sydnone-benzoylhydrazone with lead oxide to 2,5-disubstituted-1,3,4-oxadiazole,sydnone hybrid derivativesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2009Kuo-Chen Chiang The mild oxidation of sydnone-benzoylhydrazone hybrids with lead oxide in acetic acid/dichloromethane solution inducted their intramolecular cyclization to provide the corresponding 2,5-disubstituted-1,3,4-oxidiazole derivatives. The sydnone moiety has been efficient preserved for the future work in the mild oxidation. J. Heterocyclic Chem., (2009). [source] | ||||||||||||||||||||||