scholarly journals Thermal behavior of corn starch granules modified by acid treatment at 30 and 50°C

2008 ◽  
Vol 33 (3) ◽  
pp. 13-18 ◽  
Author(s):  
C. Beninca ◽  
I. M. Demiate ◽  
L. G. Lacerda ◽  
M. A. S. Carvalho Filho ◽  
M. Ionashiro ◽  
...  

Unprocessed native starches are structurally too weak and functionally too restricted for application in today's advanced food technologies. Processing is necessary to engender a range of functionality. Naturals or natives starches can be modified by using several methods physical, chemical, enzymatic or combined, according industrial purposes. In this work, native corn starch was hydrolyzed by hydrochloric acid solution and investigated by using thermoanalytical techniques (thermogravimetry - TG, differential thermal analysis - DTA and differential scanning calorimetry - DSC), as well as optical microscopy and X-ray diffractometry. After acid treatment at 30 and 50°C, a decrease of gelatinization enthalpy (ΔHgel) was verified. Optical microscopy and X-ray diffractometry allowed us to verify the granules contorn and rugosity typical of cereal starches.

2018 ◽  
Vol 39 (4) ◽  
pp. 21
Author(s):  
Gilbert Bannach ◽  
Rafael R. Almeida ◽  
Luis G. Lacerda ◽  
Egon Schnitzler ◽  
Massao Ionashiro

Several papers have been described on the thermal stability of the sweetener, C12H19Cl3O8 (Sucralose). Nevertheless no study using thermoanalytical techniques was found in the literature. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC) and infrared spectroscopy, have been used to study the thermal stability and thermal decomposition of sweetener.


2006 ◽  
Vol 31 (1) ◽  
pp. 21-30 ◽  
Author(s):  
E. C. Rodrigues ◽  
A. B. Siqueira ◽  
E. Y. Ionashiro ◽  
G. Bannach ◽  
M. Ionashiro

Solid-state M-4-MeO-Bz compounds, where M stands for trivalent La, Ce, Pr, Nd and Sm and 4-MeO-Bz is 4-methoxybenzoate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, polymorphic transformation, ligand's denticity, thermal behaviour and thermal decomposition of the isolated compounds.


1999 ◽  
Vol 72 (1) ◽  
pp. 165-173 ◽  
Author(s):  
D. J. Burlett

Abstract Elastomers are used in many industrial applications because of their remarkable toughness and elasticity. However, the source of these properties is also a weakness, in that loss of properties via oxidation is an important factor in their selection. Thermoanalytical techniques, such as differential scanning calorimetry (DSC), provide useful tools for the characterization of the stability of elastomers. DSC can not only be used to determine oxidative induction times under isothermal conditions but can also be used to determine apparent overall activation energies of the oxidation process. An evaluation of these techniques is made and the technique is used to compare the oxidation susceptibility of polybutadienes of different microstructure. The results of these DSC scans are interpreted in terms of the chemistry of the oxidation process using FTIR results.


2008 ◽  
Vol 1134 ◽  
Author(s):  
Xiaobing Shan ◽  
Pei-xuan Wu ◽  
Lin Zhang ◽  
Zhong-Yang Cheng

AbstractSingle-wall and multi-wall carbon nanotube blends (0 to 0.5 vol% ) with polyvinylidene fluoride (PVDF) have been prepared using solution cast method and characterized. By acid treatment, it has been observed that nanotube has been well functionalized and uniformly dispersed into the polymer. X-ray diffraction analysis coupled with differential scanning calorimetry (DSC) has revealed that carbon nanotube alters the crystallinity of PVDF and thereby enhances the β-phase in PVDF. Experimental results have demonstrated that enhancement of β-phase is a function of carbon nanotube concentration.


2019 ◽  
Vol 12 (1) ◽  
pp. 78
Author(s):  
Takanori Fukami ◽  
Shuta Tahara ◽  
Arbi Dimyati

Manganese L-tartrate dihydrate, L-MnC4H4O6·2H2O, and manganese DL-tartrate dihydrate, DL-MnC4H4O6·2H2O, crystals were grown at room temperature by the gel method using silica gels as the growth medium. Differential scanning calorimetry, thermogravimetric-differential thermal analysis, and X-ray diffraction measurements were performed on both crystals. The space group symmetries (monoclinic P21 and P2/c) and structural parameters of the crystals were determined at room temperature. Both structures consisted of slightly distorted MnO6 octahedra, C4H4O6 and H2O molecules, and O–H···O hydrogen-bonding frameworks between adjacent molecules. Weight losses due to thermal decomposition of the crystals were found to occur in the temperature range of 300–1150 K. We inferred that the weight losses were caused by the evaporation of bound 2H2O molecules, and the evolutions of gases from C4H4O4 and of (1/2)O2 gas from MnO2, and that the residual black substance left in the vessels after decomposition was manganese oxide (MnO).


2010 ◽  
Vol 35 (4) ◽  
pp. 93-100 ◽  
Author(s):  
J. R. Locatelli ◽  
C. T. Carvalho ◽  
F. J. Caires ◽  
M. Ionashiro

Solid-state Ln-L compounds, where Ln stands for heavy trivalent lanthanides (Tb-Lu) and L is malonate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, TG-FTIR system, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The dehydration of the compounds begins at 303 K and the anhydrous compounds are stable up to 548 K. The results also provided information concerning the ligand's denticity, thermal behaviour and identification of some gaseous products evolved during the thermal decomposition of these compounds.


2005 ◽  
Vol 30 (3) ◽  
pp. 7-13 ◽  
Author(s):  
A. C. Vallejo ◽  
A. B. Siqueira ◽  
E. C. Rodrigues ◽  
E.Y. Ionashiro ◽  
G. Bannach ◽  
...  

Solid-state M-3-MeO-Bz compounds, where M stands for bivalent Mn, Co, Ni, Cu and Zn and 3-MeO-Bz is 3-methoxybenzoate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, and chemical analysis were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated compounds.


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