Depilation of skins by pure enzymes / S. Priya in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 5 (09-10/2008)

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 5 (09-10/2008) . - p. 214-221 Titre : Depilation of skins by pure enzymes Type de document : texte imprimé Auteurs : S. Priya, Auteur ; A. Rajaram, Auteur ; R. Rajaram, Auteur ; T. Ramasami, Auteur Année de publication : 2008 Article en page(s) : p. 214-221 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux Epilage enzymatique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Five pure enzymes (pepsin, trypsin, chymotrypsin, elastase and papain) were used indepilation of goatskins in order to find alternatives to current methods (involving lime and sulphide). The morphologies of depilated skins and hair roots were investigated by both optical microscopy and scanning electron microscopy. There were differences in morphology depending on the possible region of attack of these enzymes at the hair root. Trypsin and elastase were very effective in unhairing with the latter having a generally extensive effect whilepapain was less so. Pepsin and chymotrypsin were ineffective. The capacity of the enzymes for depilation has also been analyzed in terms of the availability of suitable sites for each of them for cleavage of the various proteins at the hair root and their propensity to cleave has been analyzed through the proteomics tools of the Swiss-Prot program. The results have indicated that theoretical predictions can be correlated to the experimental observations on the depilation of the skin. Note de contenu : - MATERIALS AND METHODS : 1) Treatment of skins with proteolytic enzymes - 2) Histology - 3) Scanning Electron Microscopy of depilated skins and hair roots - 4) Analysis of number of cleavage sites in the proteins based on specificity of enzyme action - RESULTS : 1) Histological assessment of the depilation process - 2) SEM investigations of the structure of the enzyme treated skin - 3) SEM investigations of the structure of the hair root from enzyme treated skin - 4) Analysis of the number of cleavage sites in proteins and propensity for cleavage - Fig. 1 : Histology of skins. Optical micrographs of sections of skin depilated b different enzymes and after scudding - fixed with formalin. Sections were stained with haematoxylin and eosin. - Fig. 2 : Scanning Electron Micrographs (SEM) of skin surfaces depilated by enzymes - Fig. 3 : SEMs of hair roots skin subjected to different enzyme treatments shown at both low and high magnification - Table 1 : Cleavage sites available for proteolytic enzymes on proteins of the epidermis, hair and dermis - Table 2 : Efficacy of enzymes trypsin and chymotrypsin in cleaving the proteins present in the epidermis, hair and dermis Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35254 [article]

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Development of natural colours in Cr-Fe tanned garment leathers / J. R. Rao in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 86, N° 3 (05-06/2002)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 86, N° 3 (05-06/2002) . - p. 106-111 Titre : Development of natural colours in Cr-Fe tanned garment leathers Type de document : texte imprimé Auteurs : J. R. Rao, Auteur ; Palanisamy Thanikaivelan, Auteur ; J. Malathi, Auteur ; R. Rajaram, Auteur ; Balachandran Unni Nair, Auteur Année de publication : 2002 Article en page(s) : p. 106-111 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acacia et constituants chataigner et constituants Chrome Colorimétrie Croûte (cuir) On entend par "cuir en croûte" des cuirs ayant subi les opérations jusqu'au tannage, à l'exclusion de toute opération de corroyage ou de finissage, mais qui, par opposition aux wet-blue ont été séchés. Cuirs et peaux -- Propriétés physiques Cuirs et peaux -- Teinture Fer Myrobalan et constituants Quebracho Le quebracho est un arbre à écorce ligneuse, mesurant 30 mètres de haut, à feuilles tannées et à fleurs tubulées blanches. Quebracho est l'un des noms communs, en espagnol, d'au moins trois espèces similaires d'arbres originaires du Gran Chaco, en Amérique latine : Schinopsis lorentzii (quebracho colorado santiagueño), de la famille des Anacardiaceae ; Schinopsis balansae (quebracho colorado chaqueño), de la même famille ; Aspidosperma quebracho-blanco (quebracho blanc), de la famille des Apocynaceae. Ces trois espèces sont riches en tanin et fournissent un bois très dur, particulièrement résistant. Leur nom provient de l'espagnol quiebrahacha, qui signifie brise-hache. Réflectance Résistance à l'abrasion Tanins végétaux Tannage minéral Tannage dans lequel interviennent différents minéraux. Le plus répandu est le tannage aux sels de chrome, mais aussi à l’aluminium Vêtements en cuir Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Dyes based on synthetic formulations are widely used in the leather industry, however, many aryl amine dyes are restricted due to their carcinogenic nature. Environmental concern leads one to look for the dye products based on natural resources, which may have advantages of biodegradability and lower toxicity. We aimed to create an eco-friendly dyeing process by forming in-situ complexes between vegetable tannins and the Cr-Fe tanning salt, where the use of iron salts results in various colours on reaction with various vegetable tannins. Sheepskins were tanned using the Cr-Fe tanning salt and treated with various vegetable tanning materials, brown, black and grey shades were developed. The shades obtained have been quantified by reflectance measurements and compared by visual assessment. Strength characteristics of the leathers treated with 5% vegetable tannins are higher than those treated with 1% tannins, bulk properties not being affected with the increase in concentration from 1 to 5%. The light, wet and dry rub fastness of the naturally coloured leathers are good with no change on ageing. Colour reproduction at bulk level production is acceptable with minor batch variations. Note de contenu : - EXPERIMENTAL DETAILS : Process details for larger scale trials - Physical testing - RESULTS AND DISCUSSION : Wattle - Chestnut - Myrobalan - Quebracho - Environmental Perception - Table 1 : Percentage reflectance measurement for garment leathers coloured with various concentrations of wattle - Table 2 : Visual assessment data of the garment samples treated with various concentrations of wattle (Grade points 0-poor and 10-very good) - Table 3 : Visual assessment data of the garment samples treated with various concentrations of chestnut (Grade points 0-poor and 10-very good) - Table 4 : Visual assessment data of the garment samples treated with various concentrations of myrobalan (Grade points 0-poor and 10-very good) - Table 5 : Percentage reflectance measurement for garment leathers coloured with various concentrations of quebrancho - Table 6 : Visual assessment data of the garment samples treated with various concentrations of quebracho (Grade points 0-poor and 10-very good) - Table 7 : Strength characteristics for various crust garment leathers - Table 8 : Visual assessment data for garment leathers treated with selected concentrations of vegetable tannins - Table 9 : Fastness of the naturally coloured leathers treated with selected concentration of vegetable tannins to wet, dry rubbing and artificial light - Table 9 : Comparison of colour measurements data between the sample and bulk colouration of leathers using selected concentration vegetable tannins En ligne : https://drive.google.com/file/d/1cy6baDBVvluD26gKPLzG7iFzZjo83l1w/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39924 [article]

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