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.     

磷脂酶用于大豆油脱胶的研究

植物油的酶法脱胶是一种新的大豆油脱胶方法。利用新型微生物磷脂酶Lecitase Ultra进行大豆油脱胶的研究,探讨了若干操作参数对大豆油脱胶效果的影响,确定了该酶较优的反应条件:反应时间200 min,加酶量25 mg/kg,pH值4.8,温度46~48℃,大豆油含磷量能降到4.7 mg/kg。结果表明,Lecitase Ultra应用于植物油脱胶效果好且稳定,是一种更适宜于工业化应用的酶种。     

Degumming,dewaxing and refining

Degumming, dewaxing and refining are aimed at removing certain fat-soluble impurities. The different operations can be done separately or in various combinations depending on, e.g., the type of feedstock and the desired refining result. State-of-the-art of water degumming and chemical (alkali) refining are discussed with special emphasis on quality and yield of products and byproducts. Dewaxing, which is of special interest for some oils such as sunflower oil, maize oil and ricebran oil, can be performed either by a filtration process or by centrifugal separation in connection with water degumming or alkali refining.     

Degumming and refining practices in Europe

European practices for degumming and refining various vegetable oils are reviewed. Special attention is given to specific processes differing from those commonly used in the U.S. and to the practical problems of day-to-day operations.     

山桐子油脱胶工艺研究

文章比较了不同脱胶剂对山桐子油脱胶效果的影响,重点研究了磷酸法脱胶工艺,研究结果表明:适宜的脱胶工艺为反应温度80℃,搅拌15 min,脱酸剂用量为1.2%,本试验中搅拌速度对脱胶效果没有影响;山桐子油中以非水化磷脂为主,磷脂酸与溶血磷脂酸钙镁盐在毛油中所占比例相当。     

棉秆皮脱胶工艺比较研究

以纤维的可挠度、残胶率、木质素为指标,对棉秆皮的三种脱胶工艺进行比较。实验结果表明,碱煮时间、碱的浓度等因素对棉秆皮纤维的残胶率影响较大;在一煮中加入亚硫酸钠和硫化钠,可以减少棉秆皮纤维中的木质素含量;棉秆皮纤维中木质素含量较小,纤维的可挠度较大。     

Degumming and bleaching ofLesquerella fendleri seed oil

A lesquerella species (Lesquerella fendleri) being investigated as a domestic source of seed oil containing hydroxy fatty acids shows good agronomic properties and is being tested in semi-commercial production.Lesquerella fendleri seeds contain 25% oil, of which 55% is lesquerolic acid (14-hydroxy-cis-11-eicosenoic). Oils produced in pilot-plant quantities by screw press, prepress-solvent extraction and extrusion-solvent extraction processes have been refined in the laboratory by filtering, degumming and bleaching. Two American Oil Chemists’ Society (AOCS) standard bleaching earths and two commercial earths were compared for effectiveness in bleaching these dark, yellow-red, crude lesquerella oils. Free fatty acids (1.3%), iodine value (111), peroxide value (<4 meq/kg), unsaponifiables (1.7%) and hydroxyl value (100) were not significantly affected by degumming and bleaching, but phosphorus levels of 8–85 ppm in the crude oils were reduced to 0.5–1.1 ppm in the degummed and bleached oils. Crude oils had Gardner colors of 14, which were reduced to Gardner 9–11 in the degummed and bleached oil, depending on bleach type and quantity used. AOCS colors in the range of 21–25R 68–71Y were obtained. By including charcoal in the bleaching step, a considerably lighter oil could be obtained (Gardner 7).     

Production of silk sericin/silk fibroin blend nanofibers

Silk sericin (SS)/silk fibroin (SF) blend nanofibers have been produced by electrospinning in a binary SS/SF trifluoroacetic acid (TFA) solution system, which was prepared by mixing 20 wt.% SS TFA solution and 10 wt.% SF TFA solution to give different compositions. The diameters of the SS/SF nanofibers ranged from 33 to 837 nm, and they showed a round cross section. The surface of the SS/SF nanofibers was smooth, and the fibers possessed a bead-free structure. The average diameters of the SS/SF (75/25, 50/50, and 25/75) blend nanofibers were much thicker than that of SS and SF nanofibers. The SS/SF (100/0, 75/25, and 50/50) blend nanofibers were easily dissolved in water, while the SS/SF (25/75 and 0/100) blend nanofibers could not be completely dissolved in water. The SS/SF blend nanofibers could not be completely dissolved in methanol. The SS/SF blend nanofibers were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, and differential thermal analysis. FTIR showed that the SS/SF blend nanofibers possessed a random coil conformation and ß-sheet structure.     

Degumming,refining and bleaching soybean oil

This subject deals with the removal of the fat-soluble impurities from crude soybean oil. These impurities may be present in true solution or in a colloidal state; their effective removal is necessary to achieve quality standards for end-use products. The processing step options for the removal of these impurities in any given situation are easily defined; the conditions and practices used, however, are the primary concern of this paper. International trading of soybean oil mandates the degumming step. The increased use of import/export soybean oil increases the importance of this processing practice. Pretreatment and effective contact time are the critical issues. Refining, as a specific process, deals primarily with free fatty acid removal, with or without simultaneous degumming as a single-step operation. State-of-the-art wet, chemical refining practices are described, and the current limitations and future opportunities for the physical refining of soybean oil are discussed. The importance of the bleaching step cannot be overstated and it should be noted that color reduction is only coincidentally achieved. The primary function of the bleaching process is to remove oxidative breakdown products, and the degree or level of treatment should be consistent with that objective. Underbleaching and thermal decolorization (deodorization) of soybean oil are misguided practices. Once “cleaned-up” through adequate bleaching, an oil should be guarded against thermal/oxidative abuse.     

蚕丝酶脱胶工艺的研究

从蚕丝中提取蚕丝素蛋白,通过改变温度、时间、浴比三个因素,并利用单因素实验以及正交实验分析结果,研究酶法的脱胶效果。通过结果分析可知,酶脱胶法在浴比1∶100,水浴温度40℃,酶处理时间20 min,脱胶率最高为26.73%,且脱胶效果优良。     

菠萝叶纤维脱胶工艺研究进展

菠萝叶纤维是从菠萝叶中提取的一种天然植物纤维,具有抗菌、除臭、快速吸收和蒸发水分等良好的品质与独特的性能,是国内外争相开发的保健绿色材料,而脱胶是其前处理的关键一步。文章综述了菠萝叶纤维不同脱胶工艺的研究进展,简要评价了化学脱胶、生物脱胶、物理脱胶工艺的优缺点,并对优化脱胶条件以及联合脱胶方法的探索提出了展望。     

欧洲大麻纤维的组成结构及脱胶研究

大麻纤维的品质既取决于原麻品质,又与其脱胶工艺息息相关。原麻纤维会因产地不同而带来化学成分含量等的不同,因而将欧洲大麻与其他产地,包括黑龙江、六安及东营的大麻纤维的化学成分、形态和聚集态结构进行了对比,并采用超声波-微波工艺对欧洲大麻进行了后续的脱胶研究。结果表明:原麻品质方面,欧洲大麻的纤维素含量较高,与东营大麻的纤维素含量相差无几,木质素含量最低;脱胶工艺方面,经超声波预处理后的欧洲大麻纤维的微波最佳脱胶工艺为碱液浓度为10 g/L、微波时间为50 min,最终大麻纤维的胶质去除率和残胶率分别为77.45%和7.50%。     

Insight into the Enzymatic Degumming Process of Soybean Oil

An enzymatic degumming trial of soybean oil was carried out at a capacity of 400 tons/day by applying microbial phospholipase A₁ from Thermomyces lanuginosus/Fusarium oxysporum. When the pH was kept in the range of 4.8–5.1, less than 10 mg/kg of phosphorous content of The oil was obtained. The gum and oil were easily separated after centrifugation and the oil loss was minimal under the process conditions. Through analysis of phospholipids compounds in the gum by Electrospray Ionization-Mass Spectrometer and phosphorous content, it could be seen that both glycerophospholipids and lysophospholipids existed with contents of 45.7 and 54.3%, respectively. The performance of enzymatic degumming was found to be related to the production of glycerophospholipids.     

Bromination of silk fabrics

The bromination of silk fabrics was studied under heterogeneous conditions in N,N-dimethylformamide using three reagent systems, molecular bromine, methanesulfonyl bromide (MsBr), and N-bromosuccinimide (NBS)-triphenylphosphine (PPh₃) in combination with sodium bromide. Molecular bromine brominated tyrosine residues selectively and consecutively to 3-bromotyrosine and 3,5-dibromotyrosine residues. MsBr reacted only with serine residues to give 3-bromoalanine (Br-Ala) residues. The addition of sodium bromide to the NBS-PPh₃ system suppressed the bromination of tyrosine residues and slightly increased the yield of Br-Ala residues. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2031–2036, 1997     

PIXE analysis of silk

The method of proton-induced X-ray emission (PIXE) was first utilized to analyze the elements in silk. Different kinds of silk from home and the wild were examined. The results show that every silk, besides C, H, O, and N, contains many types of elements such as Si, P. S, Ca, Mn, Fe, Cu, Zn, and Sr and different samples have different relative contents. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 405–408, 1997     

从丝素水溶液中再生的丝纤维的结构与性能

通过使用表面皿直接拉伸、毛细管重力纺丝和人工拉伸3种不同的成丝方法,从高浓度再生丝素水溶液中制得了丝纤维。用偏光显微镜观察了丝纤维的取向,用拉曼光谱仪和Instron拉力仪表征了丝纤维的结构和力学性能。结果发现,经毛细管剪切流动后再拉伸有利于再生丝性能的提高,所得的丝有较好的取向和较多的β折叠结构,力学性能也相对较好。剪切在丝纤维的成形过程中起重要的作用。     

Degumming of crude soybean oil by ultrafiltration using polymeric membranes

In this study, the ability of two ultrafiltration polymeric membranes to perform the degumming of a crude soybean oil/hexane mixture is tested. The performance of both membranes is defined in terms of their permeation flux, permeate color, and rejection of phospholipids. One of the membranes was synthesized in our laboratories from polyvinylidenefluoride (PVDF); the other one is a commercially available membrane made of polyimide. The degumming experiments were done in a stirred dead-end ultrafiltration cell pressurized with N₂. Results show that tested membranes are suitable for removing phospholipids from the crude oil/hexane miscella in the range of temperature and transmembrane pressure utilized in this work. Both membranes have high selectivity regarding phospholipids and produce a moderate reduction in permeate color. The PVDF membrane gives permeate fluxes up to threefold larger than those obtained with polyimide membrane at the same operational conditions, making the former more suitable for use at industrial scale.     

Preparation of electrospun silk fibroin nanofibers from solutions containing native silk fibrils

Electrospinning solutions containing native silk fibrils with varied diameter and length were firstly achieved by dissolving silk in CaCl₂/Formic acid solvents. The structure of nanofibrils significantly improved the spinnability of electrospinning solution. The diameter of electrospun silk fibroin (SF) nanofibers increased from 40 nm to 1.8 μm, which could be achieved through increasing the solution concentration from 2 to 10%, implying a good size control over a wide range in this process. The structure of SF nanofibers transferred from random coil to beta‐sheet, before and after ethanol treatment, respectively. The mechanical properties of the SF nanofibers were improved significantly with stress and strain at break of 11.15 MPa and 7.66% in dry state, and 3.32 MPa and 174.0% in wet state. The strategy for preparing SF nanofibers with improved mechanical properties and fiber diameter control over a wide range provides benefits for the application of this material. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41236.     

陶瓷膜超滤薏苡仁混合油脱胶

研究了陶瓷膜在薏苡仁混合油脱胶中的应用。研究了不同截留相对分子质量陶瓷膜的脱胶效果以及过膜压力、料液温度和运行时间对膜通量的影响,并对陶瓷膜清洗工艺进行探索。选择截留相对分子质量15 000的超滤膜,在50 ℃和0.5 MPa下能够去除混合油中90%磷脂。用碱洗和次氯酸钠清洗能够彻底去除膜污染,恢复膜通量。