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Effect of chrominium in blue hides on activity of microbial transglutaminase / Maryann M. Taylor in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CV, N° 6 (06/2010)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CV, N° 6 (06/2010) . - p. 175-180 Titre : Effect of chrominium in blue hides on activity of microbial transglutaminase Type de document : texte imprimé Auteurs : Maryann M. Taylor, Auteur ; J. Lee, Auteur ; Lorelei P. Bumanlag, Auteur ; Eduard Hernàndez Balada, Auteur ; Eleanor M. Brown, Auteur Année de publication : 2010 Article en page(s) : p. 175-180 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Microbial transglutaminase (mTgase) has been used in the modification of proteins from sustainable resources to make products that have application in leather production. It has also been successfully used to treat blue stock, prior to addition of the products, for the purpose of stabilizing the fillers and lessening the chance that they will be washed out during further processing steps. There is always a concern that metals may have an effect (either positively or negatively) on the enzyme's activity and literature has addressed many of these issues. However, one area that has not been addressed is whether chromium may affect activity of mTgase. Even though we have only seen positive results after hide treatment with enzyme, we designed an experiment to elucidate this matter. Using Atomic Absorption Spectroscopy (AAS), we first determined the concentration of chromium in the floats during the processing of the hides. When the hides were washed and then neutralized, the concentration of unbound chromium was found to be less than 5 ppm. Next, to test mTgase sensitivity, we carried out activity assays in absence and presence of chromium and found that activity results were similar. We prepared a model system in which gelatin, swollen and solubilized in solutions containing chromium, was reacted with mTgase using standard conditions. It was found, when compared to a control, that the reaction proceeded at the same rate (chemical gel formed in 2 h @ 50°C), and the physical properties and molecular weight distributions (SDS-PAGE) of the products were similar. Finally, epi-fluorescent microscopy studies showed that enzyme-pretreatment, when compared to a control in which no enzyme pretreatment was applied, prevented migration of the fillers during subsequent processing steps. Thus, under the conditions in which we treat wet blue hides, the chromium used to tan the hides does not affect enzyme activity Note de contenu : EXPERIMENTAL : MATERIALS METHODS : Treatment of blue stock for chromium analyses of floats - Treatment of gelatin with enzyme - Treatment of blue stock for epi fluorescent microscopy studies. ANALYSES : Measurement of mTgase activity - Physical properties, molecular weight distribution and chromium analysis - Epi-fluorescent microscopy. RESULTS AND DISCUSSION : Chromium analyses of treatment floats - Reaction of gelatin with mTgase in presence of chromium - Epi-fluorescent microscopy studies of treated blue stock. En ligne : https://drive.google.com/file/d/1QPR2TZzLFNQkDcYtt-XjGCN0CEa8sy65/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9452 [article]

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Studies on the removal of inter-fibrillary materials. Part II : removal of protein, proteoglycan and glycosoaminoglycans from biobased pre-tanning process / Balaraman Madhan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CV, N° 6 (06/2010)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CV, N° 6 (06/2010) . - p. 181-188 Titre : Studies on the removal of inter-fibrillary materials. Part II : removal of protein, proteoglycan and glycosoaminoglycans from biobased pre-tanning process Type de document : texte imprimé Auteurs : Balaraman Madhan, Auteur ; M. Dineshkumar, Auteur ; Jonnalagadda Raghava Rao, Auteur ; Balachandran Unni Nair, Auteur Année de publication : 2010 Article en page(s) : p. 181-188 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Eco-concerns are forcing the leather industry to shift itself from chemical based processing to bio-processing. The use of enzymes for unhairing and bating has been long established and well reported ; but the use of a-amylase for fiber opening is a recent development, which advocates the complete elimination of lime. Though the bio-based fiber opening process is established to be an eco-friendly alternative, it is essential to establish its effectiveness versus the conventional liming process by more objective methods. Hence in this work an attempt has been made for quantitative analysis or interfibrillary materials viz., proteins, proteoglycans and glycosoaminoglycans (GAGs) released from the skin matrix by the use of complete enzyme based beamhouse process, especially the effect of a-amylase in beamhouse processes. It is observed that treatment of 2 % a-amylase for a time period of 180 min is sufficient for the removal of optimum amount of inter-fibrillary materials especially, proteoglycans. Matched pair comparison of experimental bio-based processing has been made with conventional lime base processing and it is observed that the removal of proteoglycans were comparable in both these processes. Also, the crust leathers processed from the matched pair beamhouse processes were compared for their organoleptic and strength characteristics. Both experimental bio-processed leather and conventionnally processed control leather were observed to be comparable. THis work further authenticates that a completely bio-based beamhouse process is not only eco-friendly but also results in a similar effect on the removal of inter-fibrillary material compared to conventional lime based process. Note de contenu : EXPERIMENTAL : Materials / Effect of duration of a-amylase treatment during fiber opening process / Effect of washing after fiber opening on the release of proteins, proteoglycans and GAGs / Influence of varying percentage of a-amylase on the removal of proteoglycans from beamhouse bioproces method / Matched pair comparison on the removal of protein, proteoglycans and GAGs from conventional and experimental process / physical testing and hand evaluation. RESULTS AND DISCUSSION : Effect of duration of a-amylase treatment on the removal of proteoglycan / Removal of protein, proteoglycan and GAGs : Influence of washing (time) after a-amylase based fiber opening / Influence of varying percentage of a-amylase on the removal of interfibrillary material and physical properties of the leathers / Matched pair comparison on the removal of protein, proteoglycans and GAGs from conventional and experimental process. En ligne : https://drive.google.com/file/d/1LWSav9X8M8LRJUZiSjfGY77h3htB5rUO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9453 [article]

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Optimization of chamois leather tanning using rubber seed oil / Ono Suparno in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CV, N° 6 (06/2010)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CV, N° 6 (06/2010) . - p. 189-194 Titre : Optimization of chamois leather tanning using rubber seed oil Type de document : texte imprimé Auteurs : Ono Suparno, Auteur Année de publication : 2010 Article en page(s) : p. 189-194 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Chamois leather is a popular leather article in the market, as it has unique uses for filtration, cleaning and drying. It can be produced by a chamois tannint process using rubber seed oil. Optimum condition for the tanning needs to be applied in order to obtain good quality leather and to produce the leather efficiently. In this research, optimizations of rubber seed oil offer and oxidation time in chamois tanning were investigated. The objectives of the research were to determine the optimum condition of rubber seed oil offer and oxidation time for tanning process. The experiment was conducted by tanning of goat pickle pelt using 10, 20, and 30 % of rubber seed oil for 5, 7, and 9 days of oxidation times. The chemical, physical, and organoleptic properties of the oil tanned leather were measured. This study shows that the chemical, physical, and organoleptic properties of rubber seed oil tanned leather fulfilled the quality requirements for the chamois leather. The optimum conditions for the tanning were an oil offer of 20 % and oxidation time of 9 days. The chemical properties of the leathers were pH of 8, ash content of 1.1 %, and oil content of 6 %. Their physical properties were thickness of 0.8 mm, tensile strength of 21. 3 N/mm2, elongation at break of 148 %, tear strength of 90 N/mm, and water absorption of 271 % (hours). The organoleptic properties of the leathers, i.e. softness, color, and odor, were considered good to excellent. En ligne : https://drive.google.com/file/d/1gcOadppaxnd8ti3nkrxpPsW7nwe3TKTO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9454 [article]

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Leather retanning ith hydrolyzed protein / Mariliz Gutterres in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CV, N° 6 (06/2010)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CV, N° 6 (06/2010) . - p. 195-202 Titre : Leather retanning ith hydrolyzed protein Type de document : texte imprimé Auteurs : Mariliz Gutterres, Auteur ; Igor Vigannico da Silva, Auteur Année de publication : 2010 Article en page(s) : p. 195-202 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Large quantities of solid waste containing chromium are generated by the leather industry. In recent years the specialized literature has described protein and chromium recovery processes. The molecular weight spectrum of the recovered protein shows that for retanning purposes the average molecular weight is too low. This study aimed to obtain an environmentally friendly protein modification process to generate high molecular weight proetin to be used in the retanning step of leather wet processing. The aim was to test potential modifications to hydrolyzed protein using different tanning agents to generate retanning products The retanning agents developed were applied in experiments on leather retanning, where the influence of the addition of vegetable tannin was aslo evaluated. The controlled variables were molecular weight of the tanning preparations, leather characteristics (compressibility, density, physical-mechanical resistance, grain firmness, and color) and the COD of the wastewater. The results obtained indicated the possibility to use hydrolyzed protein combined with glutaraldehyde as a retanning agent to obtain good quality leather. En ligne : https://drive.google.com/file/d/1FgWx0jBbDShjAo0U-01vSt8sivKGKXDu/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9455 [article]

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