Effects of Chemical Preservatives and Storage on Constituents Used to Characterize Lemon Juice

1968 ◽  
Vol 51 (1) ◽  
pp. 6-10
Author(s):  
Carl E Vandercook ◽  
Henry C Guerrero
Keyword(s):  
Room Temperature ◽  
Total Phenolics ◽  
Chemical Characterization ◽  
Lemon Juice ◽  
Potassium Sorbate ◽  
Practical Applications ◽  
Regression Approach ◽  
And Storage

Abstract The effects of sulfur dioxide, sodium benzoate, and potassium sorbate preservatives on the analytical methods for chemically characterizing lemon juice were studied. None of the preservatives had any effects on the analyses for total acidity as citric acid, the l-malic acid, the UV absorbance at the 330 m/x peak (referred to as the total phenolics), or the formol determination of total amino acids (after expelling the S02 by boiling 1 min). The study was continued over storage periods of up to 17 weeks at room temperature and 6 weeks at 30 °C. The constituents measured remained relatively stable except for some small but statistically significant changes that were apparently a function of both the juice and, in the case of the total phenolics, the preservative used. For practical applications, the changes did not affect the multiple regression approach to the chemical characterization of lemon juice

Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

1988 ◽  
Vol 46 ◽  
pp. 880-881
Author(s):  
Bradley L. Thiel ◽  
Chan Han R. P. ◽  
Kurosky L. C. Hutter ◽  
I. A. Aksay ◽  
Mehmet Sarikaya
Keyword(s):  
Grain Boundary ◽  
Cuprous Oxide ◽  
Room Temperature ◽  
Boundary Phase ◽  
Spectroscopic Techniques ◽  
Transition Width ◽  
Practical Applications ◽  
Thin Foils ◽  
Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

Processing by Pulsed Laser Deposition and Structural, Morphological and Chemical Characterization of Bi-Pb-Sr-Ca-Cu-O and Bi-Pb-Sb-Sr-Ca-Cu-O Thin Films

2010 ◽  
Vol 75 ◽  
pp. 202-207
Author(s):  
Victor Ríos ◽  
Elvia Díaz-Valdés ◽  
Jorge Ricardo Aguilar ◽  
T.G. Kryshtab ◽  
Ciro Falcony
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Chemical Characterization ◽  
Laser Deposition ◽  
Nominal Composition ◽  
Deposition Parameters ◽  
The Relationship

Bi-Pb-Sr-Ca-Cu-O (BPSCCO) and Bi-Pb-Sb-Sr-Ca-Cu-O (BPSSCCO) thin films were grown on MgO single crystal substrates by pulsed laser deposition. The deposition was carried out at room temperature during 90 minutes. A Nd:YAG excimer laser ( = 355 nm) with a 2 J/pulse energy density operated at 30 Hz was used. The distance between the target and substrate was kept constant at 4,5 cm. Nominal composition of the targets was Bi1,6Pb0,4Sr2Ca2Cu3O and Bi1,6Pb0,4Sb0,1Sr2Ca2Cu3OSuperconducting targets were prepared following a state solid reaction. As-grown films were annealed at different conditions. As-grown and annealed films were characterized by XRD, FTIR, and SEM. The films were prepared applying an experimental design. The relationship among deposition parameters and their effect on the formation of superconducting Bi-system crystalline phases was studied.

Physico-Chemical Characterization of Alumina Sols Prepared From Aluminum Alcoxides

1986 ◽  
Vol 73 ◽  
Author(s):  
William L. Olson
Keyword(s):  
Room Temperature ◽  
Gel Filtration ◽  
Chemical Characterization ◽  
Process Conditions ◽  
Chemical Processing ◽  
Rotary Evaporation ◽  
Physico Chemical ◽  
Elution Curves ◽  
Alumina Sol

ABSTRACTAlumina sols derived from aluminum sec-butoxide (Yoldas) were characterized. The distribution of the polymer sizes within the sol, determined by gel filtration chromatography (GFC), was found to be dramatically affected by small changes in the chemical processing or preparative procedure. Aging the sol at room temperature for two weeks produced no significant change in the GFC elution curves of the alumina sol. Sols with a “milky” appearance were found to exhibit a wider distribution of polymers by GFC than transparent sols. Rotary evaporation of the sol followed by redissolution of the residue was found to change the polymer size distribution described by the gel filtration elution curves. These observations coupled with 27Al NMR spectroscopy and viscometry measurements were used to elucidate the effects of process conditions and aging on the molecular structure of the sol.

scholarly journals Physical, Chemical-physical and chemical characterization of must and integral juice in grape cultivars

2017 ◽  
Vol 10 (3) ◽  
pp. 1 ◽  
Author(s):  
I. T. S. Viana ◽  
G. V. A. Fonseca ◽  
G. H. Bueno ◽  
J. O. F. Melo
Keyword(s):  
Chemical Characterization ◽  
Grape Juice ◽  
Titratable Acidity ◽  
Mineral Elements ◽  
Flame Emission ◽  
Level Of Significance ◽  
Physical And Chemical ◽  
Grape Cultivars

In recent years there has been an important increase in the production of grape derivatives such as integral grape juice. Thus, it was intended with the accomplishment of this study to evaluate the composition of the grape juice of the grape cultivars: Bordô, Concord e Isabel in the composition of integral grape juice from the Bento Gonçalves-RS. The samples were evaluated for classical analysis:°Brix, pH, titratable acidity, ratio Brix / titratable acidity made through methods, physics, physical chemistry and chemistry. The mineral elements sodium and potassium analyzed by flame emission and color intensity by colorimetry. For the statistical analysis of the data, the Tukey test was applied at the 5% level of significance. The contents of integral grape juice evaluated, SS, A Tand minerals presented according to the legislation, the pH was within the comparative average with other works. The determination of the color demonstrated the need to make cuts.

Production and Characterization of Exopolysaccharides from Loss Cooked Sweet Potatoes (Ipomoea batatas) by Lactobacillus Plantarum

2021 ◽  
Vol 2 (7) ◽  
pp. 01-11
Author(s):  
Robert Germain Beka ◽  
Emmanuel Akdowa Panyoo ◽  
Germaine Yadang ◽  
Pamela Homsi ◽  
Laurette Blandine Mezajoug Kenfack ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Ipomoea Batatas ◽  
Chemical Characterization ◽  
Sweet Potatoes ◽  
Fermentation Time ◽  
Total Sugars ◽  
Titrable Acidity ◽  
Lactic Acid Content

The aim of the work was to produce and characterize the exopolysaccharides from loss cooked sweet potato (Ipomoea batatas) using fermentation with Lactobacillus. The cooked sweet potato was fermented according to the factorial design with the following factors: the time (21.51h-38.48h) and the amount of Lactobacillus (1.58*106-5*106UFC). Responses were represented by production yield, pH, and titrable acidity. Characterization of the exopolysaccharides was then done by determination of total sugars, solubility index and viscosity. The results show that the pH of unfermented cooked potatoes was between 6.23 to 6.63. The pH of fermented potatoes varies from 3.96 to 4.06. The lactic acid content was found from 7.75 to 9.9% for the fermented samples. The production yields are 1.90% for the samples fermented for 21.5 hours with 3.5*106UFC of bacteria and 5.62% for those fermented for 30 hours with the same volume of inoculum. The average viscosity of the products was 4mPas regardless of the fermentation time. Chemical characterization indicates glucose contents of 68.21 and 94.01% in fermented potato for 24h and 21h respectively. The solubility index gives values of 70.3 ± 0.16 and 88.11 ± 0.23 for fermentation times of 21h and 24h respectively. Results of this work indicated that cooked sweet potatoes ferment for 21h was a promising substrate for production of exopolysaccharides.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXIV Syntheses, Spectroscopy and Structures of Some 1 : 4 Adducts of Copper(I) and Silver(I) Perchlorates with Triphenylarsine and Triphenylstibine

1997 ◽  
Vol 50 (6) ◽  
pp. 539 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Effendy ◽  
Robert D. Hart ◽  
John D. Kildea ◽  
Brian W. Skelton ◽  
...  
Keyword(s):  
Room Temperature ◽  
Far Infrared ◽  
Lewis Base ◽  
X Ray ◽  
Cation Disorder ◽  
Structure Determinations ◽  
Consistent Picture ◽  
Far Infrared Spectra

Syntheses and room-temperature single crystal X-ray structure determinations are recorded for adducts [M(EPh3)4] (ClO4), M = Cu, E = As (1), Sb (2); M = Ag, E = As (3), Sb (4), enabling comparison with analogous, previously studied MP4 and MN4 environments. The four complexes so characterized all crystallize in the familiar rhombohedral R-3 array (a ≈ 14·4, c ≈ 52 Å, hexagonal setting) with the metal and chlorine atoms located on crystallographic threefold axes. In these arrays Cu–E (axial, off axis) are 2·493(2), 2·533(1) for (1), and 2·572(1), 2·577(1) Å for (2), the disparity in the two independent M-E distances being diminished relative to those of previously studied phosphorus analogues, perhaps in consequence of increasing E size. In (3) and (4), some cation disorder is evident in respect of the ligand pnictide atom (E); for the major components Ag-E are 2·652(3), 2·680(2) in (3); 2·732(2), 2·7295(8) Å in (4). Problems associated in defining the metal atom environment geometries in the latter are, nevertheless, more satisfactorily overcome in two further determinations of nitrate salts: [Ag(SbPh3)4] (NO3) (5) is of the rhombohedral family with no cation core disorder, Ag–E (axial, off axis) being 2·720(4), 2·725(2) Å, while the structural characterization of a 1 : 4 triphenylarsine adduct of silver nitrate is recorded as its tetraethanol solvate, namely [Ag(AsPh3)4] (NO3).~ 4C2H5OH(6), monoclinic, C2/c, a 18·373(4), b 20·786(5), c 21·070(8) Å, β 108·18(3)°, Z = 4 f.u. The silver atom of the [Ag(AsPh3)4]+cation unusually lies on a crystallographic 2 (rather than a 3 ) axis of the incipiently23 (T) array, with Ag-As 2·649(2), 2·650(2) Å and As-Ag-As ranging from 108·22(4) to 111·41(6)°. The structure determination of a chloroform solvate of (2), denoted (2a), of low precision, is noted, together with the structure of an interesting artefact, isomorphous with the rhombohedral oxoanion array, modelled as [Ag(PPh3)4]2 (SiF6).py (7). Bands in the far-infrared spectra of [M(AsPh3)4] (ClO4) are assigned to v(MAs) vibrations at 119 (M = Cu) and 103 cm¯1 (M = Ag); this produces a more consistent picture of the variation in the wavenumbers of the v(ME) modes in [M(EPh3)4]+ compounds than was available previously.

Headspace Sampling and Gas Chromatographic Determination of Styrene Migration from Food-Contact Polystyrene Cups into Beverages and Food Simulants

1981 ◽  
Vol 64 (5) ◽  
pp. 1122-1130 ◽  
Author(s):  
Sandra L Varner ◽  
Charles V Breder
Keyword(s):  
Gas Chromatography ◽  
Room Temperature ◽  
Detection Limits ◽  
Chromatographic Determination ◽  
Headspace Sampling ◽  
Ionization Detector ◽  
Migration Studies ◽  
Flame Ionization ◽  
And Storage

Abstract Migration studies using coffee, tea, water, and 8% ethanol were conducted with various types of foodcontact polystyrene cups. Study conditions simulated filling and storage at room temperature and hot-filling or pasteurization above 150°F (65.6°C). The quantity of styrene migrating was determined by headspace sampling and gas chromatography (GC). The GC column was 6% Carbowax 20M on Chromosorb 101 with quantitation via a flame ionization detector. Detection limits ranged from 3 to 10 ppb in various liquids. The method and results of the migration studies are presented.

Free Standing CVD Diamond Shapes and Coatings

1989 ◽  
Vol 162 ◽  
Author(s):  
Donald E. Patterson ◽  
Robert H. Hauge ◽  
John L. Margrave
Keyword(s):  
Film Industry ◽  
Chemical Characterization ◽  
Cvd Diamond ◽  
Thin Wall ◽  
Low Friction ◽  
Free Standing ◽  
Practical Applications ◽  
Support Materials ◽  
Physical And Chemical

ABSTRACTThe success of the emerging CVD diamond film industry will depend to a great extent on how well these films can be put to practical applications. Our research is presently focusing on the development of methods for the growth of large thin wall diamond shapes which can be subsequently strongly bonded to other support materials. The shapes such as cylinders, hemispheres, etc. will be designed to take advantage of diamond's superior hardness and thermal conductivity. As these diamond shapes also promise low friction and long wearing surfaces, they have potential uses as bearing surfaces as well as very scratch resistant covers for mirrors and lenses. Our primary research objectives will be concerned with: 1. The development of various apparatus to grow selected shapes of CVD diamond. 2. The development of techniques to transfer and bond the films onto materials other than the original substrates. 3. The physical and chemical characterization of the diamond films, composites, and final products.

scholarly journals Partial chemical characterization of antigenic preparations of chromoblastomycosis agents

1999 ◽  
Vol 41 (6) ◽  
pp. 343-350 ◽  
Author(s):  
Tania Fraga BARROS ◽  
Maria Aparecida de RESENDE
Keyword(s):  
Total Lipid ◽  
Uv Light ◽  
Chemical Characterization ◽  
Total Lipids ◽  
Lipid Contents ◽  
Carbohydrate Levels ◽  
Carbohydrate Contents ◽  
Partial Chemical

Antigenic preparations (saline, methylic, metabolic and exoantigens) of four agents of chromoblastomycosis, Fonsecaea pedrosoi, Phialophora verrucosa, Cladophialophora (Cladosporium) carrionii and Rhinocladiella aquaspersa were obtained. Partial chemical characterization of these antigenic preparations was obtained by determination of the levels of total lipids, protein, and carbohydrates, and identification of the main sterols and carbohydrates. Methylic antigens presented the highest lipid contents, whereas metabolic antigens showed the highest carbohydrate content. Total lipid, protein, and carbohydrate levels were in the range of 2.33 to 2.00mg/ml, 0.04 to 0.02 mg/ml and 0.10 to 0.02 mg/ml, respectively, in the methylic antigens and in the range of 0.53 to 0.18mg/ml, 0.44 to 0.26mg/ml, and 1.82 to 1.02 mg/ml, respectively, in saline antigens. Total lipid, protein, and carbohydrate contents were in the range of 0.55 to 0.20mg/ml, 0.69 to 0.57mg/ml and 10.73 to 5.93mg/ml, respectively, in the metabolic antigens, and in the range of 0.55 to 0.15mg/ml, 0.62 to 0.20mg/ml and 3.55 to 0.42mg/ml, respectively, in the exoantigens. Phospholipids were not detected in the preparations. Saline and metabolic antigens and exoantigens presented hexose and the methylic antigen revealed additional pentose units in their composition. The UV light absorption spectra of the sterols revealed squalene and an ergosterol fraction in the antigens. The characterization of these antigenic preparations may be useful for serological evaluation of patients of chromoblastomycosis.

scholarly journals Polyphenolic Characterization of Nebbiolo Red Wines and Their Interaction with Salivary Proteins

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1867
Author(s):  
Joana Azevedo ◽  
Elsa Brandão ◽  
Susana Soares ◽  
Joana Oliveira ◽  
Paulo Lopes ◽  
...  
Keyword(s):  
Total Phenolics ◽  
Specific Activity ◽  
Chemical Characterization ◽  
Human Saliva ◽  
Salivary Proteins ◽  
Precipitation Process ◽  
Red Wines ◽  
Polyphenolic Composition

The present study correlates the polyphenolic composition of two different Nebbiolo red wines from the 2015 vintage (M and P), with the salivary proteins’ precipitation process. The work centered on the polyphenolic characterization of Nebbiolo wines and their interaction with different families of salivary proteins. Overall, both wines were found to be very reactive with human saliva which was supposed to contribute to their astringent character. The comparison of both wines showed that the M wine presented higher values of total phenolics, total proanthocyanidins, and tannin specific activity. Moreover, this wine showed a higher interaction with salivary proteins. Altogether, the chemical characterization and reactivity toward human saliva could contribute to the wine astringency.

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