Analytical control of leather fat by near infrared reflectance spectroscopy / H. Iturriaga in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 91, N° 2 (03-04/2007)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 91, N° 2 (03-04/2007) . - p. 47-51 Titre : Analytical control of leather fat by near infrared reflectance spectroscopy Type de document : texte imprimé Auteurs : H. Iturriaga, Auteur ; S. Maspoch, Auteur ; Trinitat Canals, Auteur ; D. Rey, Auteur Année de publication : 2007 Article en page(s) : p. 47-51 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bains de trempe -- Analyse Bains de trempe -- Teneur en matières grasses Cuirs et peaux de bovins Etalonnage Extraction par solvant Spectroscopie de réflectance Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A highly expeditious method for the direct analytical control of leather fat as an alternative to the officially endorsed methods was developed based on solvent extraction. The proposed method uses multivariate calibration with partial least-squares regression (PLSR) of diffuse reflectance spectra (NIRRS) for leather specimens. The reference values of the calibration matrix are used to derive those for powdered leather extracted with methylene chloride using the official method. Two different approaches based on matrices containing spectral information for powdered leather and spectra directly recorded on unpowdered leather samples were developed. The optimum calibration model for powdered samples is based on the second spectral derivative and 3 PLS components, and provides overall relative calibration and prediction errors in the region of 5%. On the other hand, the optimum prediction model uses the first spectral derivative and 5 PLS components; the results are similarly as good as those of the calibration model, but the prediction of some external samples results in larger errors arising from the inability to construct calibration sets encompassing the whole variability of the prediction set. Fibre optic-based NIR spectroscopy in combination with multivariate calibration appears to be an effective alternative to existing methods for the analysis and control of fat in the leather tanning industry as it is a rapid method and uses no reagents. Note de contenu : - EXPERIMENTAL PROCEDURES : Leather and fat-liquoring - Samples - Apparatus and software - Recording of NIR spectra - Processing of data - RESULTS AND DISCUSSION : Powdered sample method - Direct recording method - Table 1 : Fat content in the fat-liquoring baths and values provided by the reference method (RM) - Table 2 : Relative standard errors for the calibration and prediction sets as calculated using various calibration models for the powdered (p) and unpowdered (l) samples - Table 3 : Fat content in each calibration and external prediction sample as determined using both methods (p and l) En ligne : https://drive.google.com/file/d/1jRdhYSyPRuG-TxoFtUWG6VS8NNillbld/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39032 [article]

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Auxiliary agents with non-swelling capacity used in pickling-tanning processes - Part 3 / Agusti Marsal in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 88, N° 5 (09-10/2004)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 88, N° 5 (09-10/2004) . - p. 191-196 Titre : Auxiliary agents with non-swelling capacity used in pickling-tanning processes - Part 3 Type de document : texte imprimé Auteurs : Agusti Marsal, Auteur ; Ramón Palop, Auteur ; V. Frias, Auteur ; Joaquim Font, Auteur ; J. Cot, Auteur ; Albert M. Manich, Auteur Année de publication : 2004 Article en page(s) : p. 191-196 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Agents anti-gonflement Bains de trempe -- Analyse Cuirs et peaux -- Epaisseur Eaux usées -- Analyse Epaisseur -- Mesure Naphtalène sulfonique, Acide L'acide naphtalènesulfonique est un composé aromatique de formule brute C10H8O3S, constitué d'un noyau naphtyle substitué par un groupe sulfo. Comme tous les dérivés monosubstitués du naphtalène, il existe sous la forme de deux isomères, selon que le substituant soit en position 1 ("α", ou péri) ou 2 ("β" ou amphi). Synthèse : Au plan commercial, l'acide naphtalènesulfonique est produit par sulfonation du naphtalène, effectuée par la méthode classique à base d'acide sulfurique. Les réacteurs modernes sont revêtus de verre ; les équipements plus anciens étaient en fonte ou recouverts d'émail. En général, la sulfonation du naphtalène conduit à un mélange de produits. La sulfonation du naphtalène à moins de ~100 °C est sous contrôle cinématique et produit principalement de l'acide 1-naphtalènesulfonique. La sulfonation du naphtalène à plus de ~150 °C permet un contrôle thermodynamique de la réaction et l'acide 2-naphtalènesulfonique est alors le produit principal. Dérivés : On appelle "acides naphtalènesulfoniques" les dérivés substitués de l'acide naphtalènesulfonique. Ce sont d'importants précurseur et intermédiaires chimiques, notamment dans la production de colorants, d'agents mouillants, de dispersants, de naphtols et d'entraîneurs d'air pour béton et ciment1. La production de nombreux intermédiaires pour former des colorants azoïques ou de triphénylméthane implique la sulfonation du naphtalène suivie d'une autre opération, par exemple la nitration, la réduction ou l'amination. Picklage Le picklage consiste à faire absorber à la peau en tripe une quantité importante d'acide, en présence de sel neutre (NaCl) pour réprimer le gonflement que provoquerait l'acidité du milieu. Tannage au chrome Température de retrait Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : In the last ten years, the use of various types of aromatic sulphonic acids in the pickling process to prevent swelling has been suggested by many authors. In previous papers, we studied the capacity of four commercial products to prevent acid swelling of hides during pickling: polyacrylic acid, naphthol 3-6-disulphonic acid, p-hydroxydiphenyl sulphonic acid and a blend of naphthalene and naphthol sulphonic acids. It was found that the best results were obtained using the blend of naphthalene and naphthol sulphonic acids. This process yielded leathers that could be acceptable as far as physical properties and handle are concerned. However ; this process, which also reduced the chloride content and conductivity of the residual bath when compared with a standard pickling process, presented some disadvantages such as an irregular stratigraphic distribution of chromium and a marked difference of colour between the dyed grain and flesh layers after shaving, when using a conventional chromium tanning salt. This was due to the thickness of the hides (3.0 mm) which caused problems of penetration of the chemicals. In order to solve these disadvantages, the joint use of a mixture of a blend of naphthalene and naphthol sulphonic acids with a chromium salt of low basicity and high masking capacity was recommended. Note de contenu : - INTRODUCTION : Aim of the work - EXPERIMENTAL PROCEDURE : Starting material - Non-swelling Products - Sodium chloride offer - RESULTS : Thickness after pickling - Thickness and shrinkage temperature after tannage - Analyses of the residual baths of pickling and tanning processes - Table 1 : Treatments with the studied products - Table 2 : Thickness variation (%) after pickling as a function of both salinity and type and offer of the auxiliary agents - Table 3 : Thickness variation (%) after tanning as a function of both salinity and type and offer of the auxiliary agents - Table 4 : Shrinkage temperature (°C) as a function of both salinity and type and offer of the auxiliary agents - Table 5 : Conductivity of the pickling bath (μS/cm) as a function of both salinity and type and offer of the auxiliary agents - Table 6 : Conductivity of the tanning bath (μS/cm) as a function of both salinity and type and offer of the auxiliary agents - Table 7 : Chemical Oxygen Demand (COD) of the pickling bath as a function of both salinity and type and offer of the auxiliary agents En ligne : https://drive.google.com/file/d/1-1SfLAzYNbmtFc5VZ6JlvEw9olv6rDCd/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39623 [article]

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Identification of gram-positive haloversatile bacteria in soak liquor samples and observation of their damage to sheepskin by scanning electron microscopy / Ozlem Ozbay in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 6 (11-12/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 6 (11-12/2022) . - p. 255-263 Titre : Identification of gram-positive haloversatile bacteria in soak liquor samples and observation of their damage to sheepskin by scanning electron microscopy Type de document : texte imprimé Auteurs : Ozlem Ozbay, Auteur ; Pinar Caglayan, Auteur Année de publication : 2022 Article en page(s) : p. 255-263 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bactéries -- Identification Bactéries haloversatiles Bains de trempe -- Analyse Cuirs et peaux -- Détérioration Cuirs et peaux de moutons Enzymes Une enzyme est une protéine dotée de propriétés catalytiques. Pratiquement toutes les biomolécules capables de catalyser des réactions chimiques dans les cellules sont des enzymes ; certaines biomolécules catalytiques sont cependant constituées d'ARN et sont donc distinctes des enzymes : ce sont les ribozymes. Une enzyme agit en abaissant l'énergie d'activation d'une réaction chimique, ce qui accroît la vitesse de réaction. L'enzyme n'est pas modifiée au cours de la réaction. Les molécules initiales sont les substrats de l'enzyme, et les molécules formées à partir de ces substrats sont les produits de la réaction. Presque tous les processus métaboliques de la cellule ont besoin d'enzymes pour se dérouler à une vitesse suffisante pour maintenir la vie. Les enzymes catalysent plus de 5 000 réactions chimiques différentes2. L'ensemble des enzymes d'une cellule détermine les voies métaboliques qui peuvent avoir lieu dans cette cellule. L'étude des enzymes est appelée enzymologie. Les enzymes permettent à des réactions de se produire des millions de fois plus vite qu'en leur absence. Un exemple extrême est l'orotidine-5'-phosphate décarboxylase, qui catalyse en quelques millisecondes une réaction qui prendrait, en son absence, plusieurs millions d'années3,4. Comme tous les catalyseurs, les enzymes ne sont pas modifiées au cours des réactions qu'elles catalysent, et ne modifient pas l'équilibre chimique entre substrats et produits. Les enzymes diffèrent en revanche de la plupart des autres types de catalyseurs par leur très grande spécificité. Cette spécificité découle de leur structure tridimensionnelle. De plus, l'activité d'une enzyme est modulée par diverses autres molécules : un inhibiteur enzymatique est une molécule qui ralentit l'activité d'une enzyme, tandis qu'un activateur de cette enzyme l'accélère ; de nombreux médicaments et poisons sont des inhibiteurs enzymatiques. Par ailleurs, l'activité d'une enzyme décroît rapidement en dehors de sa température et de son pH optimums. Liqueurs de tannage Microscopie électronique à balayage Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In the leather industry, the salting process is applied to raw hides in order to prevent microbial activity. Salted hides and skins are then soaked to re-absorb the water lost during salting and also to clean the salted hides and skins. Due to the organic load, salt and faeces present in the soak liquor, the soak liquor provides a suitable environment for the growth of bacteria. Bacteria that develop on the hide/skin may cause significant damage to these hides and skins. Therefore, the aims of the present study were to examine the pH values and salt saturation of the soak liquor samples, to detect the total counts of haloversatile bacteria, total counts of proteolytic haloversatile bacteria and total counts of lipolytic haloversatile bacteria in the soak liquor samples. Enzyme (amylase, caseinase, lipase, xylanase, cellulase, protease, DNase, pullulanase, urease, oxidase, or catalase) producing haloversatile bacteria were also isolated from these samples and they were identified with 16S rRNA gene sequence analysis. Their metabolic activities such as utilisation of different amino acid and carbon sources were tested. In addition, the damage caused to the skin structure by enzyme-producing haloversatile bacteria were examined using scanning electron microscope. The pH values and salt saturation of the samples were found as 8.80-9.30 and 3.5%- 5.5%, respectively. The total counts of haloversatile bacteria, proteolytic, and lipolytic haloversatile bacteria were respectively detected as 3.8 x 104-1.6 x 106CFU/mL, 1.2 x 104-5.8 x 105CFU/mL, and 6.3 x 104-4.6 x 105CFU/mL. Six haloversatile bacteria were isolated from the samples belonging to five different species such as Terribacillus halophilus, Brevibacterium luteolum, Bacillus australimaris, Bacillus siamensis, and Bacillus mojavensis. Various enzymes such as protease (83%), lipase (83%), caseinase (67%), amylase (50%), cellulase (17%) were produced by the isolates, on the other hand, none were xylanase, DNase, pullulanase and urease positive. Different sugar sources [lactose (100%), D-(+)-dextrose (100%), myo-inositol (100%), D-(+)- cellobiose (100%), adonitol (100%), D-(-)-salicin (100%), dulcitol (100%), D-mannose (100%), xylitol (83%), L-(+)-arabinose (83%), D-mannitol (67%), D-(-)-fructose (67%), D-(+)-trehalose (67%), D-(-)- ribose (50%), D-(+)-melezitose (33%) and sucrose (17%)] and different amino acid sources [L-serine (100%), L-glutamic acid (67%), DL-phenylalanine (67%), trans-4-hydroxy-L-proline (67%), L-proline (67%), glycine (50%), L-ornithine (50%), L-aspartic acid (33%), L- phenylalanine (33%), L-arginine (17%), L-histidine (17%), L-lysine (17%), L-threonine (17%)] were utilised by the isolates. D-sorbitol, D-(+)-galactose, maltose, D-(+)-xylose and D-(+)-melibiose, L-isoleucine, L-cystine, L-alanine, leucine, L-methionine, L-tyrosine and L-valine were not used. Note de contenu : - EXPERIMENTAL PROCEDURES : Soak liquor samples - Determination of temperature, pH and salinity values - Determination of total counts of haloversatile - DETERMINATION OF TOTAL COUNTS OF PROTEOLYTIC AND LIPOLYTIC HALOVERSATILE BACTERIA : Isolation of haloversatile bacteria - Determination of enzymatic activities of haloversatile bacteria - Utilisation of different amino acids and different sugars by haloversatile bacteria - 16S rRNA Sequences of DNA belonging to the haloversatile isolates - Nucleotide accession number - Examining the effects of pH, salt and temperature on haloversatile bacterial growth - Investigation of cell morphology an dpigmentation of haloversatile bacteria - Sheepskin curing process and storage - Preparation of sheepskin samples for examination under scanning electron microscope En ligne : https://drive.google.com/file/d/1pv1NXv_AA0sblUQelr9lGmsalSpOCx7c/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38518 [article]

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Isolation and identification of moderately halophilic bacteria from soak liquor samples collected of leather tanneries / Pinar Caglayan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 7 (07/2023)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVIII, N° 7 (07/2023) . - p. 293-300 Titre : Isolation and identification of moderately halophilic bacteria from soak liquor samples collected of leather tanneries Type de document : texte imprimé Auteurs : Pinar Caglayan, Auteur Année de publication : 2023 Article en page(s) : p. 293-300 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Bactéries -- Identification Bactéries -- Isolement Bactéries halophiles Bains de trempe -- Analyse Cuirs et peaux Cuirs et peaux -- Détérioration Cuirs et peaux de moutons Détérioration enzymatique Enzymes microbiennes Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Isolation and identification of protease and lipase producing moderately halophilic bacteria from soak liquor samples and studying their adverse effects to the sheepskin using scanning electron microscopy may provide critical data on decomposition of raw hide/skin materials during soaking process. Moreover, enzyme-production properties of the moderately halophilic isolates (such as catalase, oxidase, lipase, protease, urease, caseinase, amylase, cellulase, pullulanase, xylanase) were determined. The effects of different NaCl concentrations, pH and temperature values on the growth of moderately halophilic bacterial isolates were tested. In the present study, four moderately halophilic bacterial isolates were isolated and selected for further experiments. The isolated species designated as SLMHB5, SLMHB10, SLMHB12, SLMHB13 were similar to Vibrio alginolyticus, Terribacillus halophilus, Vibrio alginolyticus, and Vibrio parahaemolyticus species, respectively. Scanning electron micrographs of sheepskin samples demonstrated that enzymatic activities of moderately halophilic bacteria isolated from soak liquor samples which decomposed the skin structure. After 35-days storage period, the sheepskin sample showed bad odor, sticky appearance and hair slip. Hence, it is recommended to control these microorganisms during the soaking process with an effective antimicrobial agent. Note de contenu : - Soak liquor samples - Isolation of moderately halophilic bacteria from soak liquors - Molecular characterization of moderately halophilic isolates - GenGank accession number - Cell morphology and pigmentation of moderately halophilic isolates - Effects of NaCl, pH and temperature on moderately halohilic bacterial growth - Enzymatic activities of moderately halophilic isolates - Curing skins with enzyme producing moderately halophilic isolates and storage period - Preparation of stored skin samples for scanning electron microscope - Table 1 : Phenotypic characteristics of the moderately halophilic bacterial isolates DOI : https://doi.org/10.34314/jalca.v118i7.7857 En ligne : https://drive.google.com/file/d/1A42rj9bvYO_w8TZBnVg03im8stsdSJ3g/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39663 [article]

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Limiting microbial activity as an alternative approach of bovine hide preservation part II : impact of developed formulations on leather quality and the environment / Majher I. Sarker in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 2 (02/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 2 (02/2020) . - p. 34-62 Titre : Limiting microbial activity as an alternative approach of bovine hide preservation part II : impact of developed formulations on leather quality and the environment Type de document : texte imprimé Auteurs : Majher I. Sarker, Auteur ; Hailemichael O. Yosief, Auteur ; Cheng-Kung Liu, Auteur ; Nicholas P. Latona, Auteur Année de publication : 2020 Article en page(s) : p. 34-62 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antimicrobiens Bactéries -- Comptage Bains de trempe -- Analyse Chlorure de sodium -- Suppression ou remplacement 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 -- Conservation Cuirs et peaux -- Propriétés mécaniques Peaux brutes -- Salage Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Wet salting of bovine hide commonly utilizes 95% saturated salt solution or 40-50% salt (w/w) on raw hide weight for preservation. The salt used for the hide preservation ends up being in wastewater and generates enormous environmental pollution. To minimize the environmental pollution problem associated with the traditional method of hide preservation, alternative formulations containing antimicrobial agents and less amount of common salt (35% saturated brine) have been developed. The alternative formulations were found to be more effective in deterring microbial growth than the traditional formulation as demonstrated by the total aerobic bacterial count of the preserved hide soaking liquor. The effect of the newly developed formulations on leather quality was assessed by analyzing the mechanical properties, scanning electron microscopic images, grain pattern and organoleptic properties of the finished leather. The quality analysis of the crust leather revealed that, the leather panels produced from the traditionally and alternatively preserved hides were comparable. The environmental impact of the newly developed formulations was also evaluated by monitoring the leather processing effluents for the pollution indicators such as total solids (TS), total dissolved solids (TDS), chloride content, Chemical oxygen demand (COD) and Bio-Chemical oxygen demand (BOD). Overall, the environmental impact of the newly developed hide preserving formulation was less severe than the traditionally used formulation. Since the newly developed formulations did not affect the quality of the leather produced and their impact on the environments is minimum, they could be considered as viable options for combatting pollution problems associated with the traditional salt curing method. Note de contenu : - EXPERIMENTAL : Materials - Laboratory scale hide preservation protocol - Analysis of soaking liquor generated in leather processing - Aerobic bacterial count of the soaking liquor - yeast and molds colony count of soaking liquor - Measurement of TOC and COD in soaking liquor - BOD analysis of soaking liquor - Tanning operation of cured hides - Determination of leather quality - Microscopic leather surface analysis - RESULTS AND DISCUSSION : Effect of the developed formulations on limiting bacterial growth - Effect of the developed formulations on limiting yeasts and molds - Determination of chloride content - Measurement of TOC and COD in soaking liquor - Determination of BOD in soaking liquors - Determination of solid pollutants in soaking liquors - Quality analysis of crust leather - Grain surface analysis of leather - Surface analysis of crust leather using Scanning Electron Microscope - Determination of mechanical properties of leather - Subjective test analysis of leather DOI : https://doi.org/10.34314/jalca.v115i2.1485 En ligne : https://drive.google.com/file/d/1EJfqdxzrT-84_y8P0ZCjrYFjq3VPFK1g/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33891 [article]

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De-oiled karanja cake as potential bio-aditive for low salt raw skin preservation / V. Brinda in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 5 (05/2020)  

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Some applications of thin layer chromatography linked to flame ionisation detection (TLC/FID) in the leather industry / Jean Poré in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 66 (Année 1982)  

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Use of ultrasound in soaking for improved efficiency / Venkatasubramanian Sivakumar in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 88, N° 6 (11-12/2004)  

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