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Purevsuren, B.; Davaajav, Y.

doi:10.1023/a:1011532819792

Cited by 25 publications

(5 citation statements)

References 4 publications

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“…The total ion thermogram (TIT) profile obtained by EGA/MS of CAS shows two non-well resolved peaks, ascribable to two main degradation steps (Figure 1) and the result is in accordance with the thermogravimetric profiles (TGA) reported in the literature [69][70][71]. The first peak has a maximum at 315°C and the second one at around 430°C.…”

Section: Reference Materialssupporting

confidence: 88%

Analytical pyrolysis of proteins in samples from artistic and archaeological objects

Orsini

Federica

Bonaduce

2017

Journal of Analytical and Applied Pyrolysis

112

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The paper presents a study of proteins found in artistic and archaeological objects based on analytical pyrolysis. Proteins (mainly egg yolk and/or egg white, casein, animal glue and collagen) have been extensively used as paint binders, adhesives and varnishes in mural and easel paintings, and they can be found in archaeological findings, such as bones and skin tissues. In order to overcome limitations of wet chemical methods arising from the reduced solubility of aged proteins in samples of cultural heritage, a combination of analytical pyrolysis techniques was used to characterise reference materials, paint reconstructions and samples from different historical periods (2nd century BC-20th century AD) and geographical origins, which were collected from paintings and archaeological findings. In particular evolved gas analysis mass spectrometry (EGA/MS), pyrolysis coupled with gas chromatography/mass spectrometry (Py/GC/MS) and double shot pyrolysis/gas chromatography/mass spectrometry (DSP/GC/MS) were used. This analytical approach allowed us to characterise and differentiate the proteinaceous media, investigate their thermal behaviour and evidence changes occurring with ageing. Data clearly indicate that egg, casein and animal glue can be identified and distinguished in a sample of unknown composition using each of the analytical pyrolysis techniques used. With time though differences tend to disappear to the extent that extremely degraded samples present pyrolytic profiles extremely similar to each other, irrespective of the nature of the proteins present. The data also indicate that proteins tend to become more thermally stable with ageing, suggesting that extensive intramolecular and intermolecular aggregation, and/or covalent cross-linking occur with time

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Section: Reference Materialssupporting

confidence: 88%

Analytical pyrolysis of proteins in samples from artistic and archaeological objects

Orsini

Federica

Bonaduce

2017

Journal of Analytical and Applied Pyrolysis

112

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“…The values obtained in our study are nearly close to the values from the literature. According to the [34], the optimum temperature for pyrolysis of casein was selected as 550 °C, in which the yield of pitch is higher. Data from our experiment indicate the pyrolysis of protein at 526.71 °C with the 2.70%/min rate.…”

Section: Resultsmentioning

confidence: 99%

A New Approach for Spontaneous Silver Ions Immobilization onto Casein

Pryshchepa

Sagandykova

Pomastowski

et al. 2019

IJMS

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The work presents the kinetic and isotherm studies of silver binding on casein, which was carried out using batch sorption technique. Moreover, the influence of light irradiation on the process was shown. In order to investigate the mechanism of metal ions sorption by casein the zero, pseudo-first order kinetics and Weber-Morris intra-particle diffusion as well as Langmuir and Freundlich isotherm models were used. Furthermore, to specify more precisely, the possible binding mechanism, the spectroscopic (FT-IR—Fourier Transform Infrared Spectroscopy, Raman), spectrometric (MALDI-TOF MS—Matrix-Assisted Laser Desorption/Ionization Time Of Flight Mass Spectrometry), microscopic (SEM—Scanning Electron Microscope, TEM/EDX—Transmission Electron Microscopy/Energy Dispersive X-ray detector) and thermal (TGA—Thermogravimetric Analysis, DTG—Derivative Thermogravimetry) analysis were performed. Kinetic study indicates that silver binding onto casein is a heterogeneous process with two main stages: initial rapid stage related to surface adsorption onto casein with immediate creation of silver nanoparticles and slower second stage of intraglobular diffusion with silver binding in chelated form (metalloproteins) or ion-exchange form. Spectroscopic techniques confirmed the binding process and MALDI-TOF MS analysis show the dominant contribution of the α-casein in the process. Moreover, the treatment of silver-casein complex by artificial physiological fluids was performed.

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“…Furthermore, visible changes are observed for the sample kaz 2 in temperature interval from 55-220 °C due to the gradual softening of casein followed by its decomposition in area from 220-450 °C. Above 400 °C, no significant decomposition of samples is observed, revealing the end of the thermal degradation [29][30][31][32] . For all studied samples, the obtained biochar (about 10 -20 %) is a compact solid material with highly developed porosity structure, and the investigation of its properties will be investigated in other studies.…”

Section: Thermogravimetric Analysismentioning

confidence: 97%

Characterization of Casein Fractions – Comparison of Commercial Casein and Casein Extracted from Cow’s Milk

Siročić

Krehula

Katančić

et al. 2017

Chem.Biochem.Eng.Q.

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Biopolymer casein was isolated from cow's milk by acid coagulation, which was initiated by acetic acid and sodium acetate in the first, and hydrochloric acid in the second process. The casein isolated by acid coagulation, i.e. by first process, and commercial casein were separated on α-, β-, (α+κ)-and κ casein by urea fractionation. The aim of this study was to compare various properties of commercial casein fractions with casein fractions isolated from cow's milk. The structure of casein and casein fraction samples were monitored by Fourier transform infrared spectroscopy (FTIR), and the obtained vibrational bands showed structural differences between isolated and commercial casein (presence of various amino acids), as well as their fractions. Differential scanning calorimetry (DSC) was used to determine glass transition temperature. The results showed that the glass transitions of the isolated and commercial casein were below room temperature (T g = 2-30 °C) due to the destruction of the samples structure that provides molecules mobility and leads to a phase transition. Thermal degradation obtained by thermogravimetric analysis (TGA) of all samples occurred in multiple steps. From the results, it is evident that 5 mass % of the each sample degraded at significantly different temperatures (T 95 ), and it can be concluded that isolated casein and its fractions showed better heat stability than commercial casein and its fraction.

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Cited by 25 publications

References 4 publications

Analytical pyrolysis of proteins in samples from artistic and archaeological objects

Analytical pyrolysis of proteins in samples from artistic and archaeological objects

A New Approach for Spontaneous Silver Ions Immobilization onto Casein

Characterization of Casein Fractions – Comparison of Commercial Casein and Casein Extracted from Cow’s Milk

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