Analyzing the mechanism and effect of acid protease in wet blue bating process for leather production / Hao Li in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 1 (01/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 1 (01/2020) . - p. 10-15 Titre : Analyzing the mechanism and effect of acid protease in wet blue bating process for leather production Type de document : texte imprimé Auteurs : Hao Li, Auteur ; Jinzhi Song, Auteur ; Deyi Zhu, Auteur ; Yanchun Li, Auteur ; Shan Cao, Auteur ; Jing Xiao, Auteur Année de publication : 2020 Article en page(s) : p. 10-15 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Biodégradation Chrome Collagène -- Détérioration Confitage Le confitage est une action biochimique effectuée au moyen de produits enzymatiques, qui a pour but de dégrader les fibres élastiques, contribuant ainsi à augmenter la souplesse du cuir. En outre, les enzymes complètent la dégradation des résidus épidermiques, donnant ainsi une fleur plus propre et plus lisse. Cuirs et peaux -- Propriétés physiques Desmosine La desmosine est une structure moléculaire formée par l'association de quatre chaînes latérales de lysine. On la retrouve associée à l'élastine où elle forme des interconnexions (liaisons covalentes) entre les différentes fibres et participe ainsi à ses propriétés mécaniques. (Wikipedia) Elastine -- Détérioration Enzymes microbiennes Hydroxyproline Peptidases Résistance chimique Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In recent years, in order to reduce the pollution produced in beamhouse and tanning sections, more and more tanneries purchase wet blue from other factories in other regions directly used as raw materials for finished leather production thereby those polluted preliminary steps can be eliminated. Therefore, the wet blue bating process is an essential step to minimize the differences of wet blue which are purchased from different regions. In this study, the properties of different acid protease are analyzed for selecting suitable protease used for wet blue bating. The analysis of chromium tolerance of different acid proteases reveals that, Ll and L4 produced from Aspergillus have higher chromium resistance than that of produced from Bacillus. The effect of Ll and L4 on wet blue and collagen shows that the Ll has more excellent performance, in which the molecular weight of functional protein is 48 KD. By SEM and MCT analysis, Ll can successfully disperse the collagen fibers of wet blue. Furthermore, the biodegradation rates of collagen and elastin were 0.006‰ and 0.5‰, respectively. It indicates that the acid protease mainly degraded elastin but not collagen in bating process thereby ensuring production safety. This paper provides the importance references for the application and the basis for the development of mechanism of acid protease in bating process. Note de contenu : - EXPERIMENTAL : Materials - determination of chromium tolerance of acid proteases - Pretreatment of wet blue - Physical properties evaluation - Circular dichroism spectrometer analysis - Micro-structure observation - SDS-PAGE analysis - Preparation of enzymatic hydrolysate - Determination of hydroxyproline by HPLC method - Determination of desmosine in the hydrolysate by ELISA method - Calculating the biodegradation rate of collagen and elastin - RESULTS AND DISCUSSION : Chromuim tolerance evaluation - Physical properties analysis - Effect of L1 and L4 acid protease act on collagen - Enzymatic properties of L1 acid protease - Observation of the porosity or dispersion of collagen fiber (bundle) - Analyze the biodegradation rate of L1 to structural protein in wet blue DOI : https://doi.org/10.34314/jalca.v115i1.1463 En ligne : https://drive.google.com/file/d/12pIVNJ4YE3q10psriwZc0l0bZLz6G4M7/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33392 [article]

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Influence of elastin degradation on the mechanical properties of leather / Michaela Schröpfer in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIX, N° 9 (09/2014)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIX, N° 9 (09/2014) . - p. 306-313 Titre : Influence of elastin degradation on the mechanical properties of leather Type de document : texte imprimé Auteurs : Michaela Schröpfer, Auteur ; Enno Klüver, Auteur ; Michael Meyer, Auteur Année de publication : 2014 Article en page(s) : p. 306-313 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux -- Propriétés mécaniques Elastine -- Détérioration Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The influence of elastin degradation in leather on important mechanical properties was investigated. The elastin content of pelts and wet blues was determined by chromatographic analysis of desmosine, which is a specific and hydrolytically stable crosslinking. Analysis of pelts was performed directly, while chrome containing samples had to be detanned prior to analysis. It is demonstrated that elastase significantly reduces the elastin content. In contrast to often assured statements on the marked influence of elastase on softness, area yield, tensile strength and elongation of leather, our investigations showed no significant changes in the mechanical properties of leather as well as area yield, grain quality or softness after treatment with elastase. It is concluded that the impact of elastin on leather properties is generally lower than postulated before or that it is not pronounced in the dry state. Note de contenu : - EXPERIMENTAL : Production of leather and enzyme treatment - Elastin analysis - Determination of chrome content - Mechanical tests - RESULTS AND DISCUSSION : Analysis of elastin - Area measurement - Permanent elongation - Tensile strength - Loose grain and softness En ligne : https://drive.google.com/file/d/1fhGNRKKSK0nkup_ByHs7HYqJk7asw4Pp/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21868 [article]

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A rapid method for measuring elastin degradation and its application in leather manufacturing / Xu Zhang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 8 (08/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 8 (08/2020) . - p. 294-300 Titre : A rapid method for measuring elastin degradation and its application in leather manufacturing Type de document : texte imprimé Auteurs : Xu Zhang, Auteur ; Mengchu Gao, Auteur ; Chunxiao Zhang, Auteur ; Sadaqat Ali Chattha, Auteur ; Biyu Peng, Auteur Année de publication : 2020 Article en page(s) : p. 294-300 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chromatographie en phase liquide à hautes performances Confitage Le confitage est une action biochimique effectuée au moyen de produits enzymatiques, qui a pour but de dégrader les fibres élastiques, contribuant ainsi à augmenter la souplesse du cuir. En outre, les enzymes complètent la dégradation des résidus épidermiques, donnant ainsi une fleur plus propre et plus lisse. Desmosine La desmosine est une structure moléculaire formée par l'association de quatre chaînes latérales de lysine. On la retrouve associée à l'élastine où elle forme des interconnexions (liaisons covalentes) entre les différentes fibres et participe ainsi à ses propriétés mécaniques. (Wikipedia) Elastine -- Détérioration Liqueurs de tannage Tannage au chrome Teneur en desmosine Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The degradation of elastin in skins during leather manufacturing can increase the yield area, softness and flatness of the leather, but, excessive degradation of elastin in leather processing induces looseness and increases veininess in the final leather product. However, the characterization of the degradation degree of elastin in skins and leathers was mostly studied through histological analysis qualitatively. There is an urgent need to develop a more efficient quantitative analytical strategy to evaluate the degradation of elastin in leather making processes. In this study, a simple and rapid HPLC method is developed for measuring elastin degradation in skins, leathers and leather processing liquors through determining the biological markers of elastin, namely desmosines. The separation of analytes was conducted on an C18 column (4.6 × 150 mm, 4.0 μm) at 30 ℃; the wavelength of diode array detector (DAD) was set at 275 nm; the mobile phases were composed of methanol and aqueous acetic acid (2.0 %, v/v). A gradient elution was carried out at a flow rate of 0.5 mL/min. It has been witnessed that Cr (III) has no effect on the retention time and peak area of desmosines, when the concentration of Cr (III) was in the range of 0 to 200 mg/L. In quantitative analysis, all of the calibration curves showed good linear regression (R2 ≥ 0.9990) within the tested ranges, and the recovery of desmosines was 100.9 % and 102.6 % for elastin hydrolysate and Cr-tanned elastin hydrolysate, respectively. The content of desmosines in elastin fiber, Cr-tanned elastin fiber and leather manufacturing liquors measured by established HPLC-DAD were comparable to the results obtained by amino acid analyzer. In the wet blue bating process, the quantitative analysis results are consistent with the histological staining results. The results demonstrate that the developed method is accurate and effective and can be readily utilized for the comprehensive process control of leather manufacturing. Note de contenu : - MATERIALS AND METHODS : Chemicals and reagents - Standard solutions - Preparation of samples - HPLC-DAD conditions - Method validation - Wet blue bating process - Determination of desmosines by amino acid analyzer - RESULTS AND DISCUSSION : Optimization of HPLC conditions - Effect of Cr(III) on des quantitation - Method validation - Determining contents of desmosines in varying leathe processing liquors - Wet blue bating process DOI : https://doi.org/10.34314/jalca.v115i8.3842 En ligne : https://drive.google.com/file/d/1wYegzMOMz23n_3RRtHL5xozXaGO0kzXm/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34436 [article]

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