Factors affecting mass transfer of protease in pelt during enzymatic bating process / Ying Song in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 10 p. Titre : Factors affecting mass transfer of protease in pelt during enzymatic bating process Type de document : texte imprimé Auteurs : Ying Song, Auteur ; Siqi Wu, Auteur ; Qian Yang, Auteur ; Hao Liu, Auteur ; Yunhang Zeng, Auteur ; Bi Shi, Auteur Année de publication : 2019 Article en page(s) : 10 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : 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 Electrostatique Peptidases Poids moléculaires Tension superficielle Transfert de masse Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Bating pelt with protease is an important process, which removes unwanted non-collagenous proteins from the pelt and moderately disperse hide collagen network. However, the grain surface, may be excessively hydrolyzed during bating due to the longer retention time of protease in the grain than in the middle layer caused by the low mass transfer rate of protease in pelt. Here, the effects of protease dosage, common auxiliaries and molecular weight of protease on protease transfer during bating were investigated so that we can find the key points to avoid excessive collagen damage, particularly in the grain. Observably, increasing protease dosage led to faster protease transfer and softer leather, but along with more considerable grain damage. Using penetrating agent JFC (fatty alcohol-polyoxyethylene ether) and ammonium sulfate enhanced protease transfer and simultaneously alleviated collagen damage due to the decrease in interfacial tension and electrostatic attraction between protease and pelt, respectively. Additionally, proteases with lower molecular weight transferred faster in pelt, which suggests that a potential strategy to solve the conflict between the mass transfer and the reaction of protease in pelt might be to produce/employ smaller bating proteases. Note de contenu : - MATERIALS AND METHODS : Materials - Effect of protease dosage on bating performance - Effect of auxiliaries on bating performance of protease - Effect of molecular weight of protease on its transfer rate during bating - RESULTS AND DISCUSSION : The effect of protease dosage on bating performance - The effect of auxiliaries on bating performance - The effect of molecular weight of protease on its mass transfer rate during bating DOI : https://doi.org/10.1186/s42825-019-0007-7 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0007-7.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36949 [article]

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Neutral protease assisted low-sulfide hair-save unhairing based on pH-sensitivity of enzyme / Yunhang Zeng in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXI, N° 9 (09/2016)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXI, N° 9 (09/2016) . - p. 345-353 Titre : Neutral protease assisted low-sulfide hair-save unhairing based on pH-sensitivity of enzyme Type de document : texte imprimé Auteurs : Yunhang Zeng, Auteur ; Qian Yang, Auteur ; Ya-Nan Wang, Auteur ; Jianfei Zhou, Auteur ; Bi Shi, Auteur Année de publication : 2016 Article en page(s) : p. 345-353 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chaux Cuirs et peaux de bovins Epilage enzymatique Peptidases Sulfure de sodium Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The mass transfer of protease in hide during enzymatic unhairing was first investigated by fluorescent tracer technique. It was found that the penetration rate of protease in hide was quite slow, and protease remained on the grain/papillary layer even after removal of hair, which is the main reason why enzymatic unhairing may cause grain damage or loose grain. But protease could effectively remove epidermis in a short time. From these phenomena, we developed an enzyme assisted low-sulfide hair-save unhairing (EALS unhairing) based on pH-sensitivity of neutral protease activity. To avoid risk of hide damage, soaked cattle hide (pH 8) was first treated with neutral protease (20 units/g hide) for 40 min at 22°C to cleave epidermis but not to unhair, and then 1% lime was immediately added both for inactivation of the neutral protease (pH>12) and for hair immunization. Finally, the hide was completely unhaired by using 0.8% sodium sulfide with intact hair shaft. The smartly controlled action of protease, as well as the synergistic effect of protease, lime and sulfide, ensured the complete removal of hair and epidermis with reduced offer of chemicals, and prevented pelts from defects. The crust leather processed by using EALS unhairing had a cleaner grain surface compared with that using conventional sulfide-lime unhairing. Additionally, the physical properties of the leather processed with EALS unhairing were comparable to those of conventional leather. Sulfide, total solids, suspended solids and chemical oxygen demand in the EALS unhairing effluent were markedly reduced due to a dramatic decrease in the input of sodium sulfide and lime as well as the recovery of hair. Note de contenu : - EXPERIMENTAL : Materials - Visualization and quantification of protease in cattle hide during enzymatic unhairing - Effect of enzymatic unhairing time on damage to hide collagen - Effect of pH on proteolytic activity on neutral protease - Effect of pH on hydrolysable action of neutral protease on collagen fiber - Comparison between low-sulfide hair unhairing (LS unhairing) and enzyme assisted low-sulfide hair-save unhairing (EALS unhairing) - Comparison between conventional sulfide-lime unhairing and EALS unhairing - RESULTS AND DISCUSSION : Penetration of protease in hide during enzymatic unhairing - Enzyme assisted low-sulfide hair-save unhairing (EALS unhairing - Comparison of conventional sulfide-lime unhairing and EALS unhairing En ligne : https://drive.google.com/file/d/1bgCly-2SyNUBAWzubdqkDIuxdO4UeG2z/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26921 [article]

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