A comparative study of ultrasonic degumming of silk sericin using citric acid,sodium carbonate and papain

The utilisation of ultrasonics has been shown to enable efficient and environmentally friendly textile wet processing. This study conducted a comparative investigation of silk degumming by using a conventional heating bath and ultrasonic irradiation at a range of ultrasonic frequencies. Citric acid, sodium carbonate and papain were used as degumming agents. Sericin degumming rate, fibre whiteness, fibre surface morphology, fibre structure characteristics and fibre tensile properties were measured and analysed. Results showed that ultrasonics at a lower frequency produced a greater degumming rate than at a higher frequency. Ultrasonics is a more effective way than the conventional heating bath of improving degumming efficiency, especially at a lowered temperature of 60 °C. When sodium carbonate was applied at 90 °C, a conventional heating bath was found to be more effective than ultrasonics. Papain was found to be more effective in sericin removal than citric acid and sodium carbonate, with a degumming rate of 22% achieved at 60 °C under ultrasonic irradiation at 40 kHz. The use of papain can, however, cause a possible overreaction to silk under certain severe conditions, resulting in a loss of fibre whiteness. Negligible changes in fibre structure characteristics were measured by Fourier Transform–infrared spectroscopy and X‐ray diffraction after ultrasonic degumming with papain. Slightly reduced fibre strength and increased fibre extensibility were observed in ultrasonically degummed silk samples compared with un‐degummed and conventionally degummed silk samples.     

Degumming of Eri silk by Sapindus (soapnut) extract and optimisation by response surface methodology

The present investigation aims to develop a method for degumming Eri silk using Sapindus (soapnut) extract and optimise it using response surface methodology (RSM). The initial experiment was conducted with 10 g/L Sapindus extract for 60 min at a boil, and the initial experiments indicated effective degumming. Further degumming experiments were conducted using RSM to optimise the process parameters, with weight loss being the primary response. The results revealed an optimised recipe for degumming was 9 g/L Sapindus extract at 92°C for 30 min, and the desirability value for this optimised recipe is 0.376. Eri silk that has been alkali-degummed loses more weight than silk degummed with Sapindus extract and soap. Comparatively speaking, degumming with Sapindus extract has a lesser impact on tensile strength than degumming with alkaline and soap. The whiteness, yellowness, brightness, and absorbency values between Sapindus extract and conventional degumming do not significantly differ. Compared with soap and Sapindus extract degumming, alkaline degummed fabric exhibits higher dye uptake. After being degummed with soap and Sapindus extract instead of alkaline, the fabric felt softer. Overall, the results show that both degumming with Sapindus extract and traditional methods are equally effective.     

Alkali degumming of decorticated ramie

The degumming action of ramie with sodium metasilicate, alone or in combination with other alkali solutions such as sodium carbonate and trisodium phosphate, has been evaluated and optimum conditions determined. The performance of degumming has been assessed in terms of weight loss, whiteness index and colour strength of the degummed fibres.     

离子液体在桑蚕丝脱胶及染色中的应用

离子液体1-丁基-3-甲基咪唑六氟磷酸盐BmimCl作为辅助试剂用于桑蚕丝的脱胶及染色过程,考察BmimCl离子液体对蚕丝脱胶率、白度及染色性能的影响。结果表明,在酸性条件下离子液体能显著提高桑蚕丝的白度,有效去除成品桑蚕丝肤色。当离子液体体积含量为5%,在pH值为2,浴比为1∶50,脱胶温度为98℃时脱胶1 h,桑蚕丝的脱胶率约为21%,白度达到80以上。以上述脱胶后的桑蚕丝进行染色,结果表明以离子液体作为辅助试剂脱胶得到的桑蚕丝的色深值达到20,同时其他染色系能也达到常规染色要求。     

Effect of fiber substrates on appearance and removal of aged oily soils

Aging of oily soils produces difficult-to-remove yellow stains on fabrics. This study examines the effect of different textile substrates on yellowing and removal of aged oily soils. Model oily, squalene and artificial sebum, were aged at 40°C on cotton, nylon, and polyester fabrics for 8 wk. Radiotracer and spectrophotometric analyses were used to quantify volatilization and color change of soiled fabrics upon aging as well as soil and color removal after laundering. Differences in volatility of oils from three substrates were insignificant, although cotton and nylon fabrics produced significantly more yellowness than polyester fabrics. Aging of oily soil enhanced detergency from all three fabrics. The largest increase in removal upon aging was found with cotton. Difference in removal from the three substrates became very small after aging. The effect of substrate was pronounced on yellowing due to aging with cotton and nylon having higher yellowness indices. Cotton visually appeared to be cleaner than indicated by the actual amount of residual oil present after washing, whereas nylon had less residual oil present even though it visually appeared more yellow than cotton. For polyester, the amount of residual oil correlated well with appearance after washing. We conclude that discoloration mechanisms differ among cotton, polyester, and nylon substrates. For polyester, discoloration is solely discoloration of oily soil that is physically bound in the fibrous structure, whereas for cotton, discoloration is a result of discoloration of oil as well as additional yellowing caused by retention of chromophores chemically bound to the cotton substrate. In the case of nylon, yellowing of nylon itself is an additional factor contributing to yellowness even though, most of the oil is removed upon washing. These results illustrate the importance of the method of detergency evaluation. Measuring color change in yellowness or reflectance is not the same as oil removal based on a quantitative measurement of soil mass. Thus, it may be necessary to measure both color and quantity of residual soil.     

The Degradation of Lignin,Cellulose, and Hemicellulose in Kenaf Bast Under Different Pressures Using Steam Explosion Treatment

The study of the main chemical composition degradation, especially cellulose degradation at high temperatures and within high moisture environments, provides important information that can guide biomass processing using steam explosion (STEX) and other similar treatments. In this paper, kenaf bast was treated using STEX at pressures of 0.5, 1.0, and 1.5 MPa. The chemical composition change and the infrared spectra were investigated. The crystalline index and degree of polymerization of kenaf cellulose were also quantified. It was found that pectin and hemicellulose could be easily degraded with the STEX treatment, while lignin only exhibited slight decomposition; cellulose degraded at 1.5 MPa STEX treatment on the kenaf. Research also indicates that cellulose with a low molecular weight can be removed with a low-pressure STEX treatment. By coupling STEX with chemical degumming process, the high-quality kenaf fiber with 7.12% residue gum content and 134.5 Nm fineness can be obtained.     

The effect of glucose oxidase enzyme on wool fibres

Glucose oxidase is a type of enzyme that converts glucose into hydrogen peroxide and gluconic acid by enzymatic reaction. Glucose oxidase is widely used in industry; however, in the textile industry, glucose oxidase has only received academic interest. Previously, wool was bleached by some reducing agents; however, currently in industry, hydrogen peroxide dominates the bleaching of wool fibres. In this study, the effect of glucose oxidase enzyme treatment on wool merino fibres and dyeability properties was investigated. Wool fibres were treated with glucose oxidase enzyme, after which the whiteness index (Stensby) and yellowness index (ASTM D 1925 and ASTM E 313) were investigated. Scanning electron microscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy were used to identify the morphological structure of wool fibres and their atomic content. The chemical damage caused by enzyme was investigated using a fluorescence and a light microscope, and the alkali solubility (ASTM D 1283) was determined. After enzymatic treatment, the wool fibres were dyed at a 2.0% concentration with reactive dyes. Dyeability (K/S) and CIELab values were assessed with a Minolta CM 3600 D spectrophotometer (D65, 10°). The washing fastness of wool fibres was investigated according to TS EN ISO 105-C06 (A1S).     

Preparation and application of ultrahigh‐pressure‐homogenised aminosilicon‐based softeners

Five different aminosilicon‐based softeners were prepared by ultrahigh‐pressure homogenisation, and changes in their particle sizes and spectroscopic properties were investigated. Moreover, the yellowing characteristics and mechanical properties of cotton fabrics treated with the homogenised softeners were determined. Homogenisation significantly decreased the average particle sizes and particle size distribution without destroying the micelles. In particular, from the results on changes in the whiteness and yellowness of a cotton fabric treated with a silicon‐based softener, it was confirmed that homogenisation suppresses the yellowing of the fabrics.     

Whiteness and fluorescence of fabrics

A method was devised for measuring the whiteness of fabrics containing optical brighteners. It is simple in operation and gives excellent agreement with the visual appraisal by 27 observers of the whiteness for fabrics with different values for their fluorescence, lightness, yellowness or blueness, and redness or greenness. The fabrics contained different quantities of various blues and optical brighteners. Apart from duplicates it requires only four measurements for each surface, viz., lightness, tristimulus amber and blue reflectance, and the tristimulus blue part of the fluorescent light. Yellowness or blueness, redness or greenness, fluorescence effect on the whiteness, whiteness without fluorescence, and whiteness including fluorescence are calculated from the measurements. The method also indicates which fabrics cannot be called “near white” because they are too gray or too strongly colored. It can be adapted to different compositions of the incident light with regard to the relative intensity of the ultraviolet and visible portions.     

Modification of Pectin and Hemicellulose Polysaccharides in Relation to Aril Breakdown of Harvested Longan Fruit

To investigate the modification of cell wall polysaccharides in relation to aril breakdown in harvested longan fruit, three pectin fractions (WSP, water soluble pectin; CSP, CDTA-soluble pectin; ASP, alkali soluble pectin) and one hemicellulose fraction (4 M KOH-SHC, 4 M KOH-soluble hemicellulose) were extracted, and their contents, monosaccharide compositions and molecular weights were evaluated. As aril breakdown intensified, CSP content increased while ASP and 4 M KOH-SHC contents decreased, suggesting the solubilization and conversion of cell wall components. Furthermore, the molar percentage of arabinose (Ara), as the main component of the side-chains, decreased largely in CSP and ASP while that of rhamnose (Rha), as branch point for the attachment of neutral sugar side chains, increased during aril breakdown. Analysis of (Ara + Gal)/Rha ratio showed that the depolymerization of CSP and ASP happened predominantly in side-chains formed of Ara residues. For 4 M KOH-SHC, more backbones were depolymerized during aril breakdown. Moreover, it was found that the molecular weights of CSP, ASP and 4 M KOH-SHC polysaccharides tended to decrease as aril breakdown intensified. These results suggest that both enhanced depolymerization and structural modifications of polysaccharides in the CSP, ASP and 4 M KOH-SHC fractions might be responsible for aril breakdown of harvested longan fruit.     

Variation in the decisions of observers regarding the ordering of white samples

The variations in the ordering of white samples by different observers have been investigated. Twenty white samples with low to high CIE whiteness indices were prepared and ranked by 22 amateur observers and the variations in the ordering decisions of the observers were compared. Results show a significant consistency between the assessments of the observers for the white samples with low indices of whiteness. However, a large level of disagreement was found between the observers for the whiter samples. In fact, the range of ranks assigned by viewers for each sample increases with an increase in the whiteness of the specimens. Distributions of the assigned orders for the samples are interpreted by considering the CIE whiteness as well as the tinting indices.     

Bioscouring and bleaching of cotton with pectinase enzyme and peracetic acid in one bath

Acidic and alkaline pectinases have proved efficient for the scouring of cotton. Peracetic acid can be used as an alternative for the bleaching of cotton. As a result of similar conditions of activity, we decided to try to scour and bleach a cotton fabric with both agents simultaneously in a single bath. Prior to performing these experiments, using the viscometric method we proved that pectinases retained their activity in the presence of peracetic acid. We tried to improve the efficiency of the single-bath treatment with the addition of a chelator. Tetrasodium pyrophosphate, which does not deactivate pectinases, has proved an efficient chelator. The analyses of a cotton fabric treated in a single bath with acidic and alkaline pectinases confirmed the efficiency of such treatment. A sufficient quantity of wax and pectin was removed and, because of that, the absorbance of the treated fabric was improved. The damage to the cotton fibres was negligible and the degree of whiteness obtained was uniform and adequate for further dyeing.     

Effect of degumming reagents on the recovery and nature of lecithins from crude canola,soybean and sunflower oils

Six reagents (water, citric acid, phosphoric acid, oxalic acid, acetic anhydride and maleic anhydride) were evaluated for their effectiveness in degumming three crude vegetable oils (canola, soybean and sunflower). All chemical reagents tested were found to be significantly more effective than water in removing lecithin material from all three oils except for acetic anhydride degumming of canola. Citric and phosphoric acids were found to be very effective in reducing phosphorus levels in canola oil (91 and 93% removal, respectively). For soybean oil, all reagents except water showed excellent degumming ability by removing 98% phosphorus, while in the case of sunflower oil, maleic anhydride and oxalic acid produced the highest level of phosphorus removal (95 and 90%, respectively). Both citric acid and acetic anhydride were effective in removing Fe from all three oils during degumming (84 to 94%), while phosphoric acid showed slightly lower values (73 to 87%). No significant changes in the phospholipid composition or fatty acid profiles of the phospholipid classes were observed as a result of degumming with the various chemical reagents. In general, canola phospholipids were lowest in palmitic, stearic and linoleic acid and contained the highest levels of oleic acid when compared to soybean and sunflower phospholipids. Both citric and acetic anhydride were found to influence the removal of an unknown glycolipid significantly. Canola lecithin was shown to contain a greater amount of glycolipids than sunflower and soybean lecithins.     

ABS树脂的色差分析

通过3组不同的考察方法,测试了ABS树脂的白度及黄色指数,通过计算数值比较产品色差。通过对放置时间、烘干时间以及对不同尺寸样件的色差分析,提出了控制ABS树脂色差的方案。     

Optimization of the Degumming Process for Aqueous-Extracted Wild Almond Oil

Wild almond (Amygdalus scoparia) oil is rich in oleic acid and, considering both nutritional and stability points of view, it can be utilized for future food applications. In the current study, acid degumming was investigated based on a method by response surface methodology using four degumming parameters, namely the amount of phosphoric acid (0.0–0.2%, w/w), the amount of water (1.0–5.0%, w/w), degumming temperature (30–70 °C), and degumming time (10–50 min). Optimum conditions for the minimum phosphorus level in the oil were found to be 0.15% phosphoric acid, 3.0% water, 40 °C degumming temperature, and 28 min degumming time, resulting in an almost complete removal of phosphorus. The final degummed wild almond oil had less than 1 mg kg⁻¹ phosphorus (reduced from an original value of 206 mg kg⁻¹). The experimental value of phosphorus reduction at optimum conditions agreed well with that predicted by the model. Peroxide value, anisidine value, iron, copper, and lead contents, phytosterols, unsaponifiable matter, and color of the oil decreased significantly during the degumming process; however, the fatty acid composition did not change. Also, degumming did not significantly impact the free fatty acid level, refractive index, density, iodine value, and the saponification value of the oil. However, tocopherols and the oxidative stability of the oil increased during degumming. Crude wild almond oil contained a trace level of amygdalin, which was completely eliminated during the degumming process.     

Eco-friendly approach on wool pretreatment and effect on the wool structure and dyeability

This research investigated the effect of various proteolytic enzymatic pretreatment on morphological and chemical features and the dyeability properties of wool fibres. Scoured merino wool fibres are treated with protease, papain, trypsin, and pepsin in specified conditions. Each enzyme activity measurement was provided by appropriate methods such as Bradford, BAPNA (N-benzoyl-1-arginine-p-nitroanilide), and BSA (Bovine Serum Albumin). Enzymatic processes were carried out for 24 h in the incubator set at 40°C, 100 rpm, and specified pH with 1 mg/ml enzyme concentration. Whiteness index (Stensby) and yellowness index (ASTM D 1925) were examined after enzymatic pretreatment. Pepsin and trypsin-treated wool fibres showed the highest whiteness index as 61.3 and 61.1, respectively whilst untreated wool fibres had 52.2. Fourier-transform infrared (FTIR) analysis revealed the increase in the intensity of amide-related bands and hydroxyl bands after enzymatic treatment. Scanning electron microscopy (SEM) photomicrographs manifested the cuticle layer is partially removed in enzyme-treated fibres. Elemental identification was provided by SEM–energy-dispersive X-ray spectroscopy (EDX). It appears that the sulphur bonds decreased after the treatment and the pepsin-treated fibres have fewer bonds of all. To examine the damage to the structure, photomicrographs were taken using fluorescence and light microscopes. The alkali solubility test (ASTM D1283) was also conducted to compare different enzyme types. Wool fibres were dyed in 2.0% concentration with reactive dyestuff. Dyeability and colorimetric features of fibres were measured by a spectrophotometer. The washing fastness test showed that all the samples have good results and the colour change after washing was better in enzyme-treated samples (grade 5) compared to untreated wool fibres (grade 4–5).     

Quantitative evaluation of perceived whiteness based on a color vision model

This article describes a new perceived whiteness index, C/V index, which focuses on the brightness‐enhancement effect of color components included in the spectral reflectance factor distribution of approximate white objects or in the spectral power distribution of illuminations. The index is developed on the basis of a color vision model. The perceived whiteness of 18 approximate white samples was evaluated, and then a predictability of the index was compared with 17 types of existing whiteness indices. As a result, the C/V index was one of the indices indicating the best predicting performance. The aforementioned findings show that the C/V index is effective in evaluating the perceived whiteness of approximate white objects and the brightness‐enhancement effect of color components is an important factor in determining the perceived whiteness. © 2009 Wiley Periodicals, Inc. Col Res Appl, 2010     

不同天然胶乳含量乳胶海绵的热氧老化行为

采用加速热空气老化的方法将2种不同天然胶乳含量的乳胶海绵（80 NR和0 NR）置于100℃条件下,通过黄度指数、白度指数、交联密度和压陷硬度等性能指标考察了其热氧老化行为,探讨了材料的热空气老化规律。结果表明,在老化过程中乳胶海绵80 NR的黄度指数始终大于0 NR,而白度指数始终小于后者。80 NR的交联密度始终要大于0 NR,所以该乳胶海绵更容易发生分子链的断裂和交联反应。80 NR的压陷硬度受老化时间的影响较明显,且会出现在较短时间内压陷硬度急剧增大的现象;0 NR的压陷硬度与老化时间呈线性相关且增幅较小。乳胶海绵0 NR的耐老化性能要优于80 NR。     

AFM和XPS分析竹沥液对竹子半纤维素返黄的影响

研究了粉单竹的竹沥液对半纤维素返黄的影响，用AFM和XPS分析半纤维素表面微观形貌和表面化学成分的变化情况，为研究高得率竹浆的返黄提供依据。实验结果表明，添加竹沥液至从粉单竹中分离出来的半纤维素，其颜色加深，由白色变为浅褐色，SEM和AFM分析发现半纤维素表面吸附着竹沥液物质，而紫外光老化处理后，XPS图谱发现光氧化引起半纤维素表面的竹沥液物质结构发生变化。研究认为竹沥液中的物质沉积在半纤维素表面上会降低竹浆白度，光老化后增加竹浆返黄程度。     

Influence of different oil-refining parameters and sampling size on the detection of genetically modified DNA in soybean oil

The degumming of crude soybean oil causes the removal of DNA, the presence of which is necessary for the detection of genetically modified organisms by polymerase chain reaction (PCR). In both chemical and physical refining processes, physical conditions of the refining steps can vary within a certain range. The extremities in this range may have a different influence on the quality and quantity of the extracted DNA. Therefore, the effects of degumming temperature, degumming time, and the amounts of water and/or acid added during degumming on the DNA quality and amplification were evaluated. Some parameters were shown to have a small influence on the quality of the DNA, but none affected the amplification of soy DNA extracted from the water fractions after the degumming. From the oil fractions, no DNA could be visualized. In this study of the ability of the degumming process to achieve the total removal of DNA from the oil fractions, the sample size during DNA extraction was increased significantly, and amplification of the soylectin genes was attempted. This resulted in a positive amplification of the lectin gene. A possible relation between the size of the test portion, the residual phosphorus content of the sample, and the PCR result is suggested.