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Biobased films prepared from collagen solutions derived from un-tanned hides / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CX, N° 2 (02/2015)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CX, N° 2 (02/2015) . - p. 25-32 Titre : Biobased films prepared from collagen solutions derived from un-tanned hides Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Nicholas P. Latona, Auteur ; Maryann M. Taylor, Auteur ; Mila Aldema-Ramos, Auteur Année de publication : 2015 Article en page(s) : p. 25-32 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Biomatériaux Calorimétrie Collagène Couches minces -- Propriétés mécaniques Cuirs et peaux Dissolution (chimie) Glutaraldéhyde Microscopie Réticulation (polymérisation) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The U.S. hide and leather industries are facing challenges of meeting environmental imperatives; quantifying, maintaining, and improving current hides and leather product quality; developing new processes and products; and improving utilization of waste. One of our contributions to address these ongoing challenges is to develop innovative uses and novel biobased products from hides to improve prospective markets and to secure a viable future for hides and leather industries. We had previously investigated the production of nonwoven and green composites from collagen fiber networks, which were extracted from un-tanned hides and from tannery solid wastes, such as splits or trimmings. Recently, we focused on preparing biobased films from un-tanned; specifically limed hides, which have potential commercial applications in medical care and food packaging. Collagen fiber networks were obtained from hides that have been processed to remove the noncollagenous materials through the hair removal and liming steps. We also focused on understanding the effects of processing steps such as bating and crosslinking treatments on the morphology and physical properties of biobased films from un-tanned hides. Results showed that the concentration of collagen solution and the methods of crosslinking with glutaraldehyde during the film formation process have significant effects on the properties of resultant films. Higher concentrations of collagen and addition of glutaraldehyde crosslinkers after solidification of the films yielded better mechanical properties. The encouraging results of this ongoing research are instrumental to produce biobased films, which have wide applications in both the medical field due to good biocompatibility and the food packaging because of excellent mechanical properties and acceptable edibility. Note de contenu : - EXPERIMENTAL : Materials and procedures. Hide fiber networks preparation - Collagen dissolution process - Crosslinking - Casting of collagen films - Mechanical property evaluations - Differential scanning calorimetry - Microscopic observations - RESULTS AND DISCUSSION : Crosslinking of films En ligne : https://drive.google.com/file/d/1U_HnDE22XzWLpr4LKJG4ncTY9Be9BKLa/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23197 [article]

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Determination of hydrolytic enzyme capabilities of halophilic archaea isolated from hides and skins and their phenotypic and phylogenetic identification / S. T. Bilgi in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CX, N° 2 (02/2015)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CX, N° 2 (02/2015) . - p. 33-42 Titre : Determination of hydrolytic enzyme capabilities of halophilic archaea isolated from hides and skins and their phenotypic and phylogenetic identification Type de document : texte imprimé Auteurs : S. T. Bilgi, Auteur ; Binnur Meriçli Yapici, Auteur ; Smaïl Karaboz, Auteur Année de publication : 2015 Article en page(s) : p. 33-42 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Bactéries -- Isolement Cuirs et peaux Enzymes protéolytiques Une enzyme protéolytique est une enzyme capable de couper une protéine en plusieurs fragments ou peptides. La trypsine, la papaïne, la pepsine, la chymotrypsine, la plasmine, la subtilisine... sont capables de couper une protéine, chaque enzyme étant spécifique de certains sites particuliers de cette protéine. C'est ainsi, par exemple, qu'une immunoglobuline G est découpée par la papaïne en un fragment Fc et deux fragments Fab, comme l'a montré Porter en 1959. Peaux brutes -- Salage Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : This research aims to isolate extremely halophilic archaea from salted hides, to determine the capacities of their hydrolytic enzymes, and to identify them by using phenotypic and molecular methods. Domestic and imported salted hide and skin samples obtained from eight different sources were used as the research material. 186 extremely halophilic microorganisms were isolated from salted raw hides and skins. Some biochemical, antibiotic sensitivity, pH, NaCl, temperature tolerance and quantitative and qualitative hydrolytic enzyme tests were performed on these isolates. In our study, taking into account the phenotypic findings of the research, 34 of 186 isolates were selected. These isolates were identified by 16S rRNA sequence analysis and 15 different strains of extreme halophilic archaea were identified. 13 strains of these were identified for first time from salted raw hide and skin in our study including Natrialba aegyptia, Halococcus thailandensis, Halococcus dombrowskii, Halovivax asiaticus, Halovivax sp. E107, Haloarchaeon, Natronococcus sp., Halorubrum sp., Halomicrobium zhouii, Natronococcus jeotgali, Haloterrigena thermotolerans, Natrinema versiforme, Halobacterium noricense. At the same time detecting Natrialba aegyptia in 6 of 8 hide samples showed that this strain is widely found in hide and skin samples. Research results are expected to contribute to other studies and solving microbial problems in leather industry. Note de contenu : - RESULTS : Qualitive findings concerning hydrolytic enzyme activities - Quantitative findings concerning hydrolytic enzyme activities - Molecular identification - DISCUSSION : Discussion findings concerning measurement of hydrolytic enzyme activity - Discussion of the finding concerning molecular identification En ligne : https://drive.google.com/file/d/1sR44uFApruPJWE2Pi5Ro2vFbltiwkQGk/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23198 [article]

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Waterborne dimethylolpropionic acid-diisocyanate adducts with alkali-deblockable isocyanate groups as pretanning agent for chrome tanning / Jie Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CX, N° 2 (02/2015)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CX, N° 2 (02/2015) . - p. 43-53 Titre : Waterborne dimethylolpropionic acid-diisocyanate adducts with alkali-deblockable isocyanate groups as pretanning agent for chrome tanning Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Zhou Xu, Auteur ; Chen Yi, Auteur ; Haojun Fan, Auteur Année de publication : 2015 Article en page(s) : p. 43-53 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Agents de tannage Bisulfite de sodium Caractérisation Collagène Cuirs et peaux -- Propriétés organoleptiques Cuirs et peaux de chèvres Diisocyanates Eaux usées -- Analyse Isocyanates Morphologie (matériaux) Propionique diméthylol, Acide Réticulation (polymérisation) Stabilité au stockage Structure chimique Tannage au chrome Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Diisocyanates qualify as tanning agent by virtue of their strong tendency to crosslink collagen molecules by reacting with amino groups. However, due to their sensitivity to water, these compounds cannot be used directly in aqueous environment, which is the basis for leather processing. To address this problem, waterborne dimethylolpropionic acid-diisocyanate adducts (WDDAs) with temporarily-blocked isocyanate terminals were prepared in the present paper by using NaHSO3 as blocking agent, and further evaluated as a pretanning agent for chrome tanning. Fourier transform infrared (FTIR) spectra revealed that the isocyanate terminals in WDDAs were successfully blocked by NaHSO3. The blocked isocyanates were stable under ambient temperature, but prone to deblocking under alkaline condition. The regenerated isocyanates were found still capable of crosslinking collagen molecules to impart hydrothermal stability. In leather tanning, a high shrinkage temperature (Ts>110°C) was achieved by successively treating goat skin with 5 wt% WDDAs and 4 wt% chrome powder. Stereomicroscope and SEM observation further indicated that the WDDA-chrome tanned leather exhibited tight grain surface and well opened up fiber structure in comparison with semi-chrome tanned leather. Due to the presence of carboxyl group in dimethylolpropionic acid, it was also found that WDDAs enhanced the absorption of chromium in the resultant leathers (% chrome uptake> 90%), resulting in significantly less Cr residual in the tanning wastewater. In addition, it is important to note that the usage of salt in pickling process was avoided owing to previous crosslinking of amino groups, which is very helpful for overcoming the problem of total dissolved solid (TDS) related to neutral salts. The tanning effect of WDDAs and their auxiliary function for chrome tanning allow them to be applicable as a pretanning agent, which efficiently alleviates the environmental impact of traditional chrome tanning for sustainability. Note de contenu : - EXPERIMENTAL PROCEDURES : Materials - Synthesis of WDDA - Characterization of WDDA - Preparation of gelatin modified by WDDA - Characterization of gelatin modified by WDDA - Tanning trial - Assessment of properties of tanned leathers - Stereomicroscope and scanning electron microscope (SEM) observation - Determination of total chromium in tanning wastewater - RESULTS AND DISCUSSION : Chemical structure of WDDAs - Storage stability of WDDAs - Conversion ratio - Reaction between WDDA and collagen - Tanning and tanning wastewater analysis - Organoleptic properties of the tanned leather - Morphologies of grain surface and fibers of the tanned leather En ligne : https://drive.google.com/file/d/1LnUCMds_IewQVvlX8zlBD7CViyxjvVgo/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23199 [article]

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Histological analysis of the skin dermal components in bovine hides stored under different conditions / S. Montelli in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CX, N° 2 (02/2015)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CX, N° 2 (02/2015) . - p. 54-61 Titre : Histological analysis of the skin dermal components in bovine hides stored under different conditions Type de document : texte imprimé Auteurs : S. Montelli, Auteur ; L. Corain, Auteur ; B. Cozzi, Auteur ; A. Peruffo, Auteur Année de publication : 2015 Article en page(s) : p. 54-61 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux -- Analyse Cuirs et peaux -- Conservation Cuirs et peaux de bovins Peau -- Histologie Peaux brutes -- Détérioration Statistique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The goal of the present study is to realize a histological study of skin samples to assess the tissue alterations at different periods and under methods of conservation (salting and refrigeration) after the skinning of the animals at the slaughterhouse. The papillary region and the reticular dermis were both analyzed. The dermal components considered were the number of cell nuclei, the structure of the collagen and elastic fibers, and finally the presence of acidic polysaccharides. Results showed a progressive reduction of cellular nuclei and acid polysaccharides of the dermal layer during the passage of time in all the conditions considered. A moderate decay of collagen bundles was noted in salted hides whereas the elastic fiber networks maintained their organization over the time. No sign of accumulation of non-functional elements or other morphological alterations were observed in the dermis. These findings can be useful for the leather industry for choosing the desired curing and timing conditions to employ during refrigeration or salt-based treatment of the skins. Note de contenu : - MATERIALS AND METHODS : Animal and specimen collection - Histological staining - Expert grader assessment for histological analysis - Statistical analysis - RESULTS AND DISCUSSION : Grain leather - Reticular dermis - Statistical analysis En ligne : https://drive.google.com/file/d/1sRDyeyiJKzEYViIJ3ybdS1tuoRpzOwec/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23200 [article]

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