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Reducing the risk of grain damage during bating of leather manufacturing : an alternative to pancreatic enzymes with alkaline protease from novel Bacillus Subtilis SCK6 / Li Fuyi in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 9 (09/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 9 (09/2020) . - p. 315-323 Titre : Reducing the risk of grain damage during bating of leather manufacturing : an alternative to pancreatic enzymes with alkaline protease from novel Bacillus Subtilis SCK6 Type de document : texte imprimé Auteurs : Li Fuyi, Auteur ; Shi Liwen, Auteur ; Tao Huadong, Auteur ; Xu Kunhua, Auteur ; Lei Xiaoying, Auteur Année de publication : 2020 Article en page(s) : p. 315-323 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Bacillus subtilis 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. Enzymes microbiennes Etudes comparatives Peptidases Trypsine La trypsine (EC 3.4.21.4) est une enzyme digestive du suc pancréatique qui a pour rôle de digérer les protéines. Elle est synthétisée par le pancréas sous forme de trypsinogène (proenzyme inactive), puis stockée dans les vésicules enzymatiques des cellules acineuses d'où elle est excrétée au moment de la digestion. L'activation du trypsinogène en trypsine est le résultat de l'hydrolyse d'un propeptide sous l'action de l'entérokinase ou par un effet d'autoactivation de la trypsine par elle-même. La cholecystokinine-pancréozymine active la sécrétion des enzymes (donc de la trypsine) dans le suc pancréatique. La trypsine est une endoprotéase qui hydrolyse les liaisons peptidiques dans lesquelles un acide aminé basique (Lys-|-Xaa ou Arg-|-Xaa) engage sa fonction acide (sauf dans le cas où l'acide aminé suivant (schématisé ici par "Xaa") est une Proline). Elle coupe en C-terminal de ces acides aminés. En d'autres mots, elle transforme les chaînes polypeptides en chaînes protéiques plus courtes pour permettre la digestion. Efficace à pH 7,5 - 8,5, elle est inactivée et digérée en quelques heures à pH neutre (=7) dans l'intestin. La trypsine participe à l'activation d'autres enzymes comme l'alpha-chymotrypsine par coupure hydrolytique de la chaîne polypeptidique du chymotrypsinogène. Cette enzyme sert également lors de la 2e semaine du développement embryonnaire humain. Elle est sécrétée par le trophoblaste afin de digérer la zone pellucide entourant le blastocyste. Ce phénomène s'appelle l'éclosion. Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Bating, using trypsin to treat delimed pelts for centuries, is the essential biotechnique in leather making processing. In this paper, the bating effects of the protease from Bacillus subtilis SCK6 to reduce the potential risk of grain pattern damage were evaluated. Activity performance of alkaline protease in bating condition was similar with trypsin. Bating of hides for furniture leather could be accomplished at a temperature range of 30°C to 40°C. Comparing with trypsin bating, the hydroxyproline concentration in alkaline protease bating liquors was lower and Cr distribution in chrome tanned leather was more even. In comparison with the trypsin treated leather, histology analysis and scanning electron microscopic graphics of alkaline protease bating pelts and leather shows less collagen damage and reduced looseness of collagen fiber and increased smoothness of grain surface. These outcomes suggest that the novel alkaline protease could be applied in bating procedure to reduce the risk of grain damage and the shortage of trypsin for leather production. Note de contenu : - MATERIALS - METHODS : Assay of caseinolytic activities of protease on casein substrate at differing pH - Effect of temperature on caseinolytic activities of protease - Determination of the stability of protease caseinolytic activities - Bating with differeint dosage of protease NGG - Bating with protease NGG at different temperature - Determination of hydroxyproline concentration in bating liquors - Determination of protein in bating liquors - Determination of carbohydrates concentrations in bating liquors - Histological analysis of collagen fibers of bated pelts - Scanning electron microscopy (SEM) analysis of crust leather - Determination of chromium content and distribution in leather - Test of physical and mechanical properties of crust leather - RESULTS AND DISCUSSIONS : Characteristics of protease activity. Effect of pH on caseinolytic activities of protease NGG - Effect of temperature and holding time on caseinolytic activities of protease NGG - INVESTINGATION OF BATING TECHNOLOGY BY THE USE OF PROTEASE NGG : Effects of dosage of protease NGG on bating - Effects temperature and time on bating - The results of the verified experiment in pilot-scale En ligne : https://drive.google.com/file/d/161RQQC658yF1tlxPBiNMtOxo7f9fXv4f/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34584 [article]

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Fungus-resistant fatliquor from blended natural oils - A sustainable lubricating product / Bindia Sahu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 9 (09/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 9 (09/2020) . - p. 324-329 Titre : Fungus-resistant fatliquor from blended natural oils - A sustainable lubricating product Type de document : texte imprimé Auteurs : Bindia Sahu, Auteur ; A. Tamil Selvi, Auteur ; Rathinam Aravindhan, Auteur Année de publication : 2020 Article en page(s) : p. 324-329 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antifongiques Caractérisation Cuirs et peaux -- Propriétés mécaniques Essais dynamiques Formulation (Génie chimique) Huiles et graisses Produits de nourriture du cuir Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Fatliquoring is an important step in making leather. It endows strength and softness to leather by lubricating its fibers. A certain amount of fungicide is also offered during the post tanning operation, to protect the leather from future fungus infection. The aim of this work is to develop a novel fatliquor, which has both lubricating and antifungal activity. Sulfated blended fatliquors were developed by blending 80:20 proportions of castor and rice bran oil respectively and then followed by reaction with Sulphuric acid at 28±2°C. The novel fatliquor was then characterized for particle size which was similar to a control (sulfated castor and sulfated rice bran ouf) fatliquor. Antifungal performance of the novel fatliquor was confirmed by agar well-diffusion process against selected fungus species such as Aspergillus piger, Aspergillus flavus and Aspergillus fumigatus. The resultant leathers were evaluated for physical strength, such as tear strength, tensile strength and lastometer test and the results were found to be similar to control leather. Our study provides additional insights for using such novel fatliquors for both antifungal and lubrication properties. Note de contenu : - MATERIALS AND METHODS : Materials - Methods (Preparation of fatliquor - Characterization of the fatliquor - Antifungal activity of the blended faltiquor - Physical characterization of fatliquored leather) - RESULTS AND DISCUSSION : Stability and particle size analysis of blended mixture - FTIR analysis of product - Antifungal activity of the product - Physical properties of fatliquored leather DOI : https://doi.org/10.34314/jalca.v115i9.3851 En ligne : https://drive.google.com/file/d/18FHAawrnLMwuU6oKvkLW_2kgJ2GOZimD/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34585 [article]

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Efficacy of aqueous solution of N-halamine to reduce microbiological contamination on cattle hides for meat safety with byproduct quality assurance / Majher I. Sarker in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 9 (09/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 9 (09/2020) . - p. 330-336 Titre : Efficacy of aqueous solution of N-halamine to reduce microbiological contamination on cattle hides for meat safety with byproduct quality assurance Type de document : texte imprimé Auteurs : Majher I. Sarker, Auteur ; Wilbert Long, Auteur ; Cheng-Kung Liu, Auteur Année de publication : 2020 Article en page(s) : p. 330-336 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antimicrobiens 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 -- Analyse Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés organoleptiques Cuirs et peaux de bovins Microbiologie Microscopie N-halamine Solutions aqueuses (chimie) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Bacterial contamination on the outer grained hide of cattle serves as a significant challenge to the meat and bide processing plants regarding food safety. Cattle serves as a host to several bacteria including pathogens, which may become firmly lodged on a cattle's bide during their lifespan and can facilitate cross contamination of the underlying meat and meat processing equipment in a slaughterhouse. In this study, the efficacy of sodium dichloroisocyanurate dehydrate (SDCIC), which belongs to N-halamine group of compounds is evaluated on inhibition of the natural-borne bacteria from the haired surface of cattle bide. Spray-washing with 0.25%, 0.50% and 0.75 % aqueous SDCIC solutions reduced total aerobic bacteria on hide surface by 1.6 and 2.37 and 3.57 log CFU/50 cm'respectively in 5 min. Similarly, in comparison with water spray, a 5 min treatment with 0.25, 0.50 and 0.75 % SDCIC resulted in a reduction of Enterobacteriaceae (ENT) and related gram-negative bacilli (gnEB) counts by 1.2, 2.22 and 4.22 log CFU/50 cm' respectively. The highest reduction of E. coli recovery of 1.48 log CFU/50 cm2 was obtained with a spray treatment of 0.75 % SDCIC in 1 minute. Likewise, 0.75 % SDCIC spray treatment resulted in 2.5 and 3.65 log CFU/50 cm2 reduction of Salmonella in 1 and 5 min, respectively in comparison to their respective controls. Leather from treated hides was tested to evaluate the effects of N-halamine solutions on structural, mechanical and subjective properties of produced leather in which no major detrimental impacts were found. Note de contenu : - EXPERIMENTAL : Materials and methods. Antimicrobial formulation preparation - Disk diffusion analysis of the developed formulations - Hide preparation - Spray treatment - Microbial testing - Leather processing - Impact of the antimicrobial treatment on leather quality - Statistical analysis - RESULTS AND DISCUSSION : Disk diffusion assay - Recovery of total aerobic bacteria - Recovery of enterobacteriaceae (ENT) and related gram-negative bacilli (gnEB) - Recovery of E. coli - Recovery of salmonella - Post-leather analysis - Microscopic analysis of crust leather - Organoleptic evaluation of leather samples - Evaluation of leather samples for mechanical properties DOI : https://doi.org/10.34314/jalca.v115i9.3852 En ligne : https://drive.google.com/file/d/1Z2NwNy_DOA-bRBv2IZc42D_cCCtrrCL7/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34586 [article]

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Preparation and characteristics of graphene-based polymeric leather fatliquor / Zhenyu Zhang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 9 (09/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 9 (09/2020) . - p. 337-346 Titre : Preparation and characteristics of graphene-based polymeric leather fatliquor Type de document : texte imprimé Auteurs : Zhenyu Zhang, Auteur ; Mengjie Cui, Auteur ; Zhonghui Wang, Auteur ; Haojun Fan, Auteur ; Yi Chen, Auteur ; Jun Xiang, Auteur ; Jun Yan, Auteur ; Jixin Ning, Auteur Année de publication : 2020 Article en page(s) : p. 337-346 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antibactériens Blindage (électricité) Caractérisation Essais (technologie) Essais de comportement au feu Oxyde de graphène Produits de nourriture du cuir Résistance au rayonnement ultraviolet Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Although the research of leather chemicals has experienced considerable advances, it remains imperative and challenging to develop functional ones ; especially functionalized fatliquors or retanning agents. In consideration with the unique structure and properties, graphene oxide (GO) has been reported as a potential alternative to ameliorate the performance of leather. However, one of the intractable handicaps is how to make graphene penetrate evenly and react with collagen fibers. Here, we demonstrate a method for preparing graphene-based polymeric fatliquor (PFGO) via an amidation reaction between amino-groups of aminated graphene (AGO) and anhydride bonds of maleic anhydride-rapeseed ouf copolymer (MRO), which was synthesized by free radical copolymerization. The results show that the as-prepared fatliquor has good emulsion stability and can penetrate into the collagen fibers uniformly. Compared with the control sample without graphene, the antibacterial, electromagnetic shielding, flame retardant and UV resistance characteristics of the PFGO-treated leather were significantly improved. Overall, this effective yet promising paradigm may provide an achievable solution toward developing graphene-based polymer composites simultaneously with high physical property and high functional performance. Note de contenu : - EXPERIMENTAL : Materials - Synthesis of GO based faltiquor (PFGO) - Fatliquoring process - CHARACTERIZATION AND PERFORMANCE TESTS : Instrument testing - Stability of fatliquor solution - SEM observation of leather - Antibacterial testing of fatliquor - Electromagnetic radiation shielding. Performance testing of leather - Flammability testing of leather - UV-resistance property testing of leather - Thermal stability testing of leather - Mechanical measurements - RESULTS AND DISCUSSION : Characterization of AGO - Characterization of fatliquor - Distribution of fatliquor in leather - Antibacterial property of fatliquor - Electromagnetic shielding performance of leather - Flammability of leather - UV-resistance of fatliquored leather DOI : https://doi.org/10.34314/jalca.v115i9.3849 En ligne : https://drive.google.com/file/d/1v5ccCkackiJzJmgK2tdNNEZKqF3muZUK/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34587 [article]

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