Exotic leather from broiler chicken leg skin: Processing and characterization

ABSTRACT. Chrome tanning material is still widely used in the tanning process for garment leather production. Its use began to be reduced to overcome its negative environment impact. Vegetable tannin of a mimosa and tara combination was used in this study to substitute chrome tanning material. Garment made from vegetable-tanned leather with a ratio mimosa to tara of 5:13 was compared to garments made from chrome-tanned leather, both the production methods and resulting leather characteristics. To obtain garment leather characteristics, chrome-tanned leather requires auxiliary materials and two fatliquoring steps. Vegetable-tanned leather requires more auxiliary materials and fatliquoring steps (3 steps). Physical test results show that chrome-tanned leather gives better tensile strength, elongation, tear strength, and softness that meet with SNI (Standar Nasional Indonesia or Indonesian National Standard). Meanwhile, garments from vegetable-tanned leather exhibit elongation, tear strength, and softness that meet with SNI. However, adding auxiliary materials and fatliquoring steps in the garment-making process from vegetable-tanned leather is still unable to produce the softness, smoothness, and elasticity of a garment from chrome-tanned leather.

Gelatin is a clear, flavorless, and colorless biopolymer formed by the denaturation of collagen protein in animal tissues. Gelatin is an important ingredient in the manufacture of capsule shell films. The tensile strength and elongation values of gelatin film indicate its quality. Sucrose is one of the ingredients that can affect the tensile strength and elongation of the gelatin film. To determine the effect of adding sucrose on the tensile strength and elongation of the chicken leg skin gelatin film. To extract the gelatin, clean, sliced chicken leg skin was freeze-dried, ground into powder, and extracted. The characteristics of chicken skin gelatin were measured using Fourier-transform infrared, and the data were read in the 4000–400 cm− 1 range for 32 scans. Pouring the solution into a mold, flattening it, and drying it at 40°C results in a film that has been tested for tensile strength and elongation. Gelatin films with a 30% sucrose addition had the best tensile strength and elongation values, with a tensile strength of 3.03 MPa and an elongation of 152.02%. Sucrose alters the tensile strength and elongation of chicken leg gelatin film. 30% sucrose provides better tensile and elongation strength.

Leather manufacturing involves a number of unit processes, out of which tanning is the most important in so far as it converts the putrescible hides/skins into non-putrescible leather. In this study, glutaraldehyde has been exploited as a means to reduce the use of basic chromium sulfate for the production of quality shoe upper crust leather. The paper consists in studying the physical properties of aldehyde-tanned leather and chrome-tanned leather. The aim is to find out the possibility of replacing the wet-blue leather, containing Cr(III) salts, with the glutaraldehyde-tanned wet-white leather. The physical properties of the aldehyde-tanned leather were evaluated, analyzed and compared with the conventional chrome-tanned shoe upper crust leather. Statistical analysis illustrated that the tensile strength, the percentage of elongation, stitch tear strength, Baumann tear strength and grain crack strength of the leather was 211±1 kg/cm2, 38±0.5 %, 89±0.11 kg/cm, 63±0.4 kg/cm and 23±0.4 kg respectively. It was observed that the property of the experimental leather was quite comparable with the conventional chrome-tanned leather and able to meet the requirements of the shoe upper crust leather after re-tanning. The shrinkage temperature of the experimental tanned leather was found to be 87 °C,lower than that of corresponding control, which indicates lesser tanning power of aldehyde. However, the morphology of the aldehyde-tanned leather was quite akin with the conventional leather. This study suggests that using glutaraldehyde in the tanning process in order to minimize the chromium load in the tanning and the re-tanning process during the production of shoe upper crust leather reduces the generation of toxic waste and its impact on the environment.

In this research, a new titanium tanning agent (TMW/2) obtained from the wastes of the metal industry was investigated in the production of chromium free eco-leather, by experimenting with various amounts of tanning agent and comparing the physical and chemical properties of the tanned leathers. The tanning process was performed with different concentrations of active titanium tanning material such as 1%, 2.5%, 5%, 7.5%, and 10%. The titanium content, chromium oxide content, formaldehyde content, shrinkage temperature, pH value, ash content, and fat content of the tanned leathers were investigated for the determination of chemical characterization. The tensile strength, elongation at break, tear strength, and colour measurement tests were also carried out for investigating the physical properties. The titanium tanned leathers had a mean shrinkage temperature of 79.5oC and more yellowish colour than the chromium tanned leathers. Their tensile strength properties were found similar with chromium leathers, while the elongation at break was found to be lower and tearing resistance was higher. The usage amount of 2.5% could be perfectly advised for the tanning process based on the titanium tanning material for achieving optimal properties required from different leather types such as upholstery, automotive and shoe upper leathers. Consequently, our results showed that this new titanium tanning agent could be used as an alternative tanning material in the production of chromium free eco-leathers considering the visual, physical, and chemical properties of resultant leathers.

UV-C irradiation critically effects the growth of micro-fungi and also deteriorate leather materials. In the present study vegetable tanned and chrome tanned leather were infected with pure cultures of Aspergillus niger and Aspergillus flavus, which were isolated from stored leather materials. UV-C light (λ = 254 nm) was applied on infected leather for 15 and 60 min. The changes in leather qualities were examined through weight, tensile strength, scanning electron microscope, energy dispersive X-ray and Fourier transform infrared spectroscopy study after 15 and 30 days of fungal inoculation. Vegetable tanned leather was more vulnerable in case of fungal attack than chrome tanned leather while A. flavus showed more influence on leather deterioration than A. niger. The results showed that weight loss after 30 days for 15 and 60 min irradiation exposure was 1.3% compared to A. flavus infected leather (3.93%). The tensile strength of vegetable and chrome tanned UV irradiated leather was increased by 44% and 7% respectively. The scanning electron microscopic images exhibit the limited presence of conidiophores in UV-C exposed leather which confirmed the potentiality of irradiation for controlling fungal growth. The infrared spectral analysis of UV-C exposed infected leather samples showed neither shifting of wavenumber nor displacement of any functional groups. Altogether the efficacy of UV-C irradiation against biodeterioration of leather was concluded to be effective. This method can be used to control fungal growth without compromising the leather quality.Graphical

This study aimed to determine the effect of syntan and mimosa combination on the quality of tanned red snapper leather. The study was designed using complete randomized design (CRD) and the advanced test of Least Significant Difference (LSD) with three replications and three treatments of combined syntan and mimosa, namely: p1 (4 % syntan, 5 % mimosa), p2 (8 % syntan, 5 %mimosa), p3 (12 % syntan, 5 % mimosa). Data were analyzed using SPSS 18. The measured parameters were tensile strength (N·cm-2), elongation (%), tear strength (N·cm-1), enervation (mm), wrinkle temperature (°C), fat/oil content (%) and water content (%). The results indicate that the combined syntan and mimosa tanners gave no significant effect on the physical parameters (tensile strength, elongation, tear strength, enervation and wrinkle temperature) and chemical parameters (moisture and fat/oil). All treatments (p1, p2 and p3) met the Indonesian National Standard (SNI) 06-4586-1998 for chrome tanned freshwater snake leather for the parameters of tensile strength, tear strength, enervation, wrinkle temperature and moisture. The parameter of elongation and fat/oil content did not meet with the SNI 06-4586-1998. Among the three combinations of a tanner, syntan 4 % and mimosa 5 % treatment gave the best leather quality.

Leather industry is one of essential industry in Indonesia, However, the production of leather products produce load of pollutions. This study aims to analyze and focuses on the addition of alkaline protease in the dehairing process and chestnut as a vegetable tanning agent in goat skin in an attempt to minimize the usage of chemicals that were detrimental to the environment despite generating good leather quality. In this study, 10 pieces of raw goat skin were used and processed from soaking to basic dyeing process. The analysis of data used One-Way ANOVA (Analysis of Variance) to discover the differences between treatments. Treatments were divided into 4 categories that were : P0: a control treatment (0% alkaline protease+ 3% H2S and 6% limes + 25% mimosa), P1: 1% alkaline protease with 2% H2S and 5% limes + 25% chestnut, P2: 1% alkaline protease with 1% H2S and 4% limes + 30% chestnut, P3: 2% alkaline protease with 1% H2S and 4% limes + 25% chestnut and P4: 2% alkaline protease with 1% H2S and 4% limes + 30% chestnut. The examination tested was the morphological observation by Scanning Electron Microscope (SEM), tensile strength, elongation, tear strength, and shrinkage temperature. The SEM study indicates the addition of alkaline protease softens the goat skin, nevertheless, there is a non-significant difference between treatments (P>0.05) on tensile strength and elongation strength, however, there is a significant difference (P<0.05) on tear strength and shrinkage temperature. The conclusion is treatment P4 (2% alkaline protease with 1% H2S and 4% limes + 30% chestnut) generates the best result.

This study aimed to evaluate the quality of sheepskin after the tanning process using mimosa and to analyze the microscopic structure of mimosa-tanned sheepskin that had been eco-printed. The research method used sheepskin samples that had undergone optimal with mimosa. The sheepskin tanning research evaluated samples subject to four different treatments: treatment A (15% mimosa), treatment B (20% mimosa), treatment C (25% mimosa), and treatment D (30% mimosa). The sheepskin eco-print research compared the sheepskin eco-print samples treated with treatment 1 (temperature 60oC), and treatment 2 (temperature 65oC). The evaluation of tanned leather quality was conducted by measuring several parameters, such as tensile strength, elongation, tear strength, thickness, plasticity, and shrinkage temperature. The quality of the sheepskin eco-print was evaluated by measuring the color fastness to rubbing, and SEM (Scanning Electron Microscopic). The data obtained were analyzed statistically using variance analysis of a complete randomized design with a unidirectional pattern. In instances where significant differences were identified, a mean difference test was performed with Duncan's Multiple Range Test. The results showed that tanning leather using mimosa, conducted in stages had a significant effect (p < 0.05) on the parameters of tensile strength, extensibility, tear strength, thickness, goldenness, and shrinkage temperature. The application of tanner with 30% mimosa on sheepskin emerged as the best tanner concentration. The treatment resulted in a tensile strength value of 1332.28 N/cm2, elongation of 45.90%, tear strength of 102.9 N/cm, thickness of 2.06 mm, plasticity of 5.33 mm, and shrinkage temperature of 81.73oC. Additionally, the results of the color fastness test against wet and dry rubbing, along with SEM from the 60oC produced good eco-print results.

PurposeThis paper seeks to report an experimental investigation on the tearing and tensile strength behaviour of military khaki fabrics from grey to finished process.Design/methodology/approachUses three different types of military fabric (3 up 1 down twill), differing in type of constituent yarns (ring/rotor) in order to test their tearing and testing strength behaviour.FindingsTearing strength of fabric is found to be very much susceptible to change due to the process variation, while fabric tensile strength is relatively less sensitive. Ring spun yarn fabric shows higher tearing strength compared with rotor spun yarn fabric. However, the difference in their tearing strength reduces substantially as the process approaches towards the finished state. On the other hand, rotor spun yarn fabric exhibits higher tensile strength along the warp. Tearing strength along bias direction is in between warp and weft wise tearing strength; whereas tensile strength is lowest while tested along the bias direction. During the grey to finished process, tear strength falls at bleaching and dyeing, and particularly drops in strength is being more at the dyeing stage.Originality/valueThis study has investigated the tearing and tensile strength behaviour of military khaki fabrics from grey to finished state, developing understanding of the impact of different processes on the tearing strength, so that fabric of the required tear strength can be developed with process modification.

The implant-supported prosthetic treatment strategy is commonly chosen in modern dentistry to address tooth loss caused by a variety of conditions or dental defects. To achieve healthy and natural-looking results in implant dentistry, it is essential to replicate the peri-implant soft tissue.The gingival tissue that surrounds implants is quite accurately replicated by gingival masks. They facilitate more accurate prosthesis restoration design, enhance periodontal health, and promote oral cleanliness. Furthermore, gingival masks allow for the accurate observation of superstructure seating on implant analogs, which is essential for creating superstructures that fit perfectly. To evaluate the change in tear strength and tensile strength of three different gingival mask materials (esthetic mask auto mix, Gi-MaskandGingifast Rigid) available in the market at various time intervals. Total of 540 specimens were fabricated with 180 samples of each group. Changes in tensile strength and tear strength of three different gingival mask materials (esthetic mask auto mix, Gi-MaskandGingifast Rigid) at intervals of one day, three days, and seven days were measured by a universal testing machine. Statistical analysis was done using one-way ANOVA and Tukey Post Hoc test.We also performed correlation and regression analyses on tear and tensile strength. The null hypothesis, which is supported by these data, claims that there is no discernible variation in the tear strength and tensile strength of three distinct materials across various time intervals. Thus, the null hypothesis was rejected, and it was concluded that there was a significant change in the tear strength and tensile strength of these gingival mask materials at different time intervals. Esthetic mask auto mix has a high tear strength compared to Gi-Mask and gingifast rigid. Gi-Mask has the least tear strength among all three. Tensile strength decreases as time increases, but the Esthetic mask auto mixhas high strength compared to Gi-Mask and gingifast rigid. Selecting the right material for gingival masks is essential, taking into account the clinical scenario and the articulation time.Time influences gingival mask materials' tear strength and tensile strength, which impacts their performance and durability. Esthetic mask auto mix has a high tear and tensile strength compared to Gi-Mask and gingifast rigid.

Biodeterioration process of chromium tanned leather with Penicillium sp.

The objective of this study was to evaluate the pelt and wastewater characteristics after deliming process in an acid condition by tartaric acid, also wet blue properties that were formed. Various observed variables were the dose of tartaric acid, pelt thickness, calcium content, physical and chemical properties of wet blue, such as tensile strength, tear strength, elongation, shrinkage temperature, and chrome oxide content, as well as the pollutants content of wastewater as chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solid (TSS), and total dissolve solid (TDS). The experiment used a completely randomized design with a factorial arrangement. The first factor was pH variables consisted of 3 levels, i.e., 4, 5, and 6 in the final deliming solution. The second factor was the deliming time consisted of 3 levels, i.e., 45 min, 60 min, and 75 min. Data were analyzed using Analysis of Variance (ANOVA) and then Duncan’s Multiple Range Test (DMRT). The results showed that deliming for 60 min and the pH of 5 at the end of the solution was the best treatment to remove calcium content in the pelt and reduce the thickness of pelt. It did not affect the physical and chemical quality, such as tensile strength, tear strength, elongation at break, and shrinkage temperature of the wet blue produced. Also, the quality of wastewater produced was better than the use of ammonium sulfate as a deliming agent. It can be concluded that the use of tartaric acid as pH regulator of deliming stage at pH 5 for 60 min can be used as an alternative deliming agent to substitute ammonium sulfate.

In this study, collagen hydrolyzate was obtained from bovine shaving wastes of leather production with the alkali hydrolysis reaction. Total amino acid, total carbon and total nitrogen amounts of liquid collagen hydrolyzate (CH) were determined. Fourier-transform infrared spectroscopy (FTIR) characterization of collagen hydrolyzate was performed. Obtained CH was emulsified with hydrogenated castor and amino functional silicone oils to prepare lubricating protein filler (LPF). Particle size and zeta potential of the LPF were analyzed. 10%, 15%, and 20% LPF was used in the retanning/fatliquoring process of chromium tanned bovine leathers. Performance characterizations of leathers treated with LPFs were carried out with tensile strength, tear strength, filling efficiency, light fastness, shrinkage, and denaturation temperature analyses. Moreover, bounded fat content in leather was also determined. Results showed the increased thermal stability, strength performance and good filling effect in leather by application of the prepared LPF. Consequently, LPF had a good potential as natural retanning/fatliquoring agent via achieving reuse of the solid leather wastes and providing satisfactory leather properties and cleaner production by one product itself.

Animal skin, a proteinaceous material containing about 60–65 % moisture, is an ideal substrate for the growth of microorganisms, if not preserved properly. Conventionally, large quantities of sodium chloride are used for skin preservation. De-salting and soaking carried out during processing of the skin generates serious environmental constraints. In view of this, low-salt skin preservation with de-oiled neem cake is attempted. To ensure the antimicrobial properties of de-oiled neem cake, aqueous and solvent extracts of the cake were studied against bacteria and fungi which were isolated from raw skin. The antimicrobial assay was performed using the well diffusion method for aqueous, methanol and hexane extract of de-oiled neem cake, which showed maximum zone of clearance for aqueous and methanolic extract against the isolated bacteria and fungi, respectively, present in raw skin. The percentage of inhibition study reveals that the methanolic extract showed 100 % inhibition against many organisms and the water extract against some organisms. The raw skin was cured using de-oiled neem cake with reduced amount of salt and left for a period of 21 days. The skins were checked periodically for microbial growth as per the conventional methods. Finally, the low-salt preserved skins were processed into chrome-tanned leathers and their strength properties were compared with leathers which were preserved by the conventional method. The results suggest that de-oiled neem cake along with minimal salt has adequate curing efficiency on raw skin and if this system is implemented, pollution caused due to sodium chloride would be significantly minimized.

The study aimed to assess the effect of protease activity of Rhizopus sp. as a bating agent on the tanned carp leather quality, and their use for commercial leather products. The study was designed with a completely randomized design with four treatment, namely: the concentration of protease from Rhizopus sp. 0.5% (a1), 1.0% (a2), 1.5% (a3) and palkobat 1.0% (a4/control) with 3 replications. Parameters were observed that is (1) protease activity of Rhizopus sp and palcobat; (2) Thickness (mm), tensile strength (N/cm2), tear strength (N/cm), elongation (%), enervation (mm), shrinkage temperature (ºC), fat/oil content (%) of tanned leather; and (3) level of consumer acceptance (%) and added valuead of comercial leather product. The data of tanned leather quality is then compared with SNI 06-4586-1998 concenring freshwater snake skin leather and chrome Burk’s Bay (1996) on the raw material quality leather products. The test results of protease activity of Rhizopus sp. = 7.97 mg/50mg/ jam and palkobat = 13.62 mg/50 mg/hour. The results of the analysis of tanned leather carp qulity sample from each treatment and comparison with the SNI as follows: (1) Thickness: 0.41 (a1), 0.38 (a2), 0.43 (a3), 0.41mm (a4) and ≥ 0.22 (SNI 06-4586-1998). Tensile strength: 1682.67; 1818.17; 1195.57; 1670.55 and 1,000N/cm2 (SNI). Tear strength: 314.87; 310.95; 332.06; 462.22, and 150.00 N/cm (SNI). Elongation: 93.33; 62.67; 56.67; 97.33, and <30.00% (SNI). Enervation: 1.87; 2.20; 1.63, 2.49, and ≥ 2.0 mm (Burk’s Bay, 1996). Shrinkage temperature: 74.00; 95.33; 96.33; 97.33, and ≥ 70.33ºC (SNI). The fat/oil content: 7.84; 8.17; 5.25; 8.49, and 2.00 to 6.00% (SNI). All treatments were tested has met the SNI quality, except elongation and fat/oil content. The level of consumer acceptance of the Oval HP Cover that is (1) aspects of the display (76.67% like and 23.33% dislike), (2) the use of convenience (66.67% like and 33.33% dislike ), and (3) price (63.33% accepted and 23.67 reject). The level of consumer acceptance of the Box Cover HP models that is (1) aspects of the display (80.00% like and 20.00% dislike), (2) convenience of use (86.67% like and 13.33% dislike), and (3) price (66.67% accepted and 33.33% reject). The economic value of tanned carp leather as big as Rp 160.000/20 leather pieces and leather products as big as Rp 420,000 per 15 pieces of product.