触蒸与丝胶的水溶性

通过触蒸对丝胶水溶性影响的研究,提出触蒸后的丝胶随着平衡时间的增加,丝胶的水溶性向难溶性方向发展的观点;并认为触蒸室温度越高,丝胶水溶性的曲线变化速率越大,触蒸时间越长,丝胶水溶性曲线越趋平缓。     

丝胶用于毛纱上浆的探索

概述了毛纱上浆的常用方法及其对浆料的要求,从水溶性、粘度、粘附力等方面详细地分析了丝胶对毛纱上浆的优势,探讨纯丝胶上浆存在的问题,设计出丝胶复配浆料的配方。     

丝胶-胰岛素结合物的制备及其生物特性研究

以天然丝蛋白为原料，应用高温高压水解法和酸降解法制备分子量范围1～7万的水溶性丝胶蛋白粉末，以戊二醛为交联剂，与注射用胰岛素交联成丝胶-胰岛素生物结合物。应用酶联免疫吸附试验(ELISA)对结合物的生物特性作初步分析，结果表明丝胶-胰岛素结合物的回收率为45．3％，体外试验表明丝胶修饰的胰岛素结合物降解速度低于牛血清(BSA)修饰的胰岛素结合物，体外半衰期是天然胰岛素的2．8倍。     

红外光谱技术分析丝胶纤维的成形及其结构性能

采用衰减全反射——傅里叶变换红外光谱（ATR-FTIR）技术分析丝胶纤维和吐丝前的天然丝胶溶液。丝胶纤维是由富含大量蚕丝丝胶的Sericin-hope蚕吐出的。偏振ATR-FTIR测定表明，丝胶纤维中的丝胶分子几乎无取向。通过傅里叶去卷积技术和曲线拟合，分析了丝胶纤维和天然丝胶的二次结构。另外，还对丝胶溶液干燥过程中的二次结构进行了分析，以确定脱水作用对丝胶结构的影响。分析表明，随着干燥程度的提高，天然胶中的β-折叠结构增多；风干丝胶的二次结构和丝胶纤维相似。以上结果说明，在纤维成形过程中，干燥是影响丝胶结构变化的一个重要因素，且与丝素相比，吐丝时丝胶的结构变化不大。     

以丝胶蛋白为细菌培养基主要成分的研究

通过对分子量小于6万的水溶性丝胶肽或者丝胶肽及其水解物以不同比例替代或完全替换普通液体培养基中主要成分蛋白胨进行的3种代表性细菌的培养试验，说明水溶性丝胶肽及其水解物营养非常丰富，是一种新型的液体培养基主要成分。     

不同烘茧温度对茧丝品质的影响

采用热风循环烘茧机对蚕茧进行干燥,探讨了不同头冲温度对生丝力学性能和丝胶结构的影响。通过一粒缫、力学性能测试、热重分析和红外光谱法分别对不同头冲温度处理后缫制生丝的力学性能、落绪分布和丝胶结构进行了研究,并用视频光学接触角测量仪观察了茧层的亲水性。研究表明,鲜茧经过高温干燥后茧层丝胶会产生热变性,理化性能发生改变,茧层丝胶的分子结构从无规卷曲向β-折叠结构转化。当头冲温度为105℃时,生丝力学性能最好,洁净成绩最高,且热稳定性最好。     

丝绸废水的膜法处理与丝胶蛋白质回收技术

为了减少丝绸生产废水中的溶解性丝胶蛋白质造成的有机物污染 ,采用中空纤维膜分离技术和离心喷雾干燥技术 ,对酸析后的煮茧制丝废水进行超滤浓缩 ,再对所回收的丝胶蛋白质浓缩液进行离心干燥制成丝胶粉 ,从而得到了纯净的丝胶蛋白质。经酸析和中空纤维膜分离技术超滤等实验处理后 ,其化学需氧量值可降至 80mg L左右 ,达到排放标准要求或制丝生产用水标准循环使用 ,并可有效回收废水中的丝胶蛋白质 ,开发出新的丝胶蛋白质副产品。     

丝胶蛋白质浓缩液的离心喷雾干燥技术研究

通过除湿方法与干燥原理分析、离心喷雾干燥实验，探讨了丝胶蛋白质浓缩液干燥方法与工艺技术参数，分析了干燥过程中丝胶蛋白质在干燥塔内发生粘肇现象的原因与克服措施，提出丝胶蛋白质浓缩液的离心喷雾干燥方法和技术要点。     

蚕茧干燥过程中丝胶结构和性质的变化

研究了蚕茧干燥过程中茧层丝胶分子构象及丝胶初期溶解性的变化。指出在蚕茧干燥过程中随着丝胶分子构象从无规卷曲向β－折叠结构的转化，茧层丝胶膨润溶解性逐步下降，变化主要发生在烘茧的头冲阶段。     

制丝副产品中萃取丝胶和丝素及其利用

本文介绍了蚕丝丝胶粉末化和水溶化，丝胶、丝素的加工，桑蚕丝综合利用的方法。     

Determination of elemental sulphur in soils

Elemental sulphur was extracted from soil with chloroform and the sulphur was reduced to hydrogen sulphide by iron powder in the presence of hydrochloric acid, acetone and chloroform. The hydrogen sulphide was transferred in a stream of nitrogen to sodium hydroxide solution and determined by titration with mercuric chloride using dithizone as an indicator. The reduction technique was not specific to elemental sulphur but soils appeared to contain few compounds which were soluble in chloroform and which were also reduced. Wet soils could be extracted without preliminary drying. The analysis is rapid and suitable to routine application.     

不同干燥方式对橄榄果粉品质的影响

比较微波干燥、热风干燥、真空干燥以及真空冷冻干燥对橄榄果粉外观色泽、物理特性、营养成分及微观结构等品质的影响。结果表明:真空冷冻干燥橄榄果粉色泽较佳,具有较高亮度和最低的红绿度,最接近鲜食橄榄绿色色泽;热风干燥和真空干燥所得果粉吸油性较低,吸湿性较高,热风干燥的果粉堆积密度和溶解度均最高,真空冷冻干燥的果粉堆积密度最低,吸湿率低,复水性、流动性、吸油性和溶解度均较高,微波干燥的果粉含水率最高,复水性、吸湿率、堆积密度、吸油性和溶解度均较低;微波干燥的还原糖、总酸含量损失较小,热风干燥的类黄酮损失较小,真空干燥的总糖和总酚含量损失较小,真空冷冻干燥的蛋白质含量损失较小。扫描电镜观察微观结构发现微波干燥和真空冷冻干燥果粉颗粒间空隙大,组织较光滑完整,皱缩少,热风干燥和真空干燥果粉颗粒间空隙小,部分皱缩。通过主成分分析品质综合得分结果为:真空冷冻干燥>真空干燥>热风干燥>微波干燥。     

Characteristics of soy sauce powders spray-dried using dairy whey proteins and maltodextrins as drying aids

This study investigated the effect of adding whey protein isolate (WPI) as a complementary drying aid of maltodextrin (MD) on spray drying of soy sauce powders. Soy sauce powders were prepared by spray drying soy sauce liquid adding 5%, 10% and 15% of WPI respectively together with MD as the drying aids. Tests were conducted to evaluate the powder properties relevant to the caking issue of the soy sauce powders. Results showed that addition of just 5% WPI could significantly increase the product yield for the spray drying process. At the same time, the caking strength of the spray dried soy sauce powders were significantly reduced during storage with WPI addition. XPS results indicated that WPI have preferential migration to the surface of the soy sauce powder. The over-expression of WPI on powder surface after spray drying might explain the improved stability for soy sauce powders during the caking test.     

丝胶蛋白的研究与应用综述

蚕丝脱胶后的丝胶溶液经过提纯、脱色、降解、浓缩、喷雾干燥可制得易溶性丝胶粉,既有效防止丝胶污水对环境的污染,又极大提高了丝胶的利用价值.易溶性丝胶粉的分子构象以无规卷曲结构为主,高聚物的聚集态结构主要是无定形结构.丝胶这一新颖的蚕丝副产品已广泛应用在保健纺织品后整理涂层材料、化妆品添加剂、保健食品、医药、功能性生物材料等领域中.开拓丝胶新用途是今后在蚕丝副产品综合利用领域中富有时代意义的应用性课题.     

Spray-dried whey protein/lactose/soybean oil emulsions. 2. Redispersability, wettability and particle structure

In the present paper redispersion and wettability experiments of spray-dried whey protein-stabilized emulsions are presented. Emulsion droplet size after redispersion gives information about eventual coalescence between emulsion droplets in the powder matrix during drying or storage, resulting in an increase in emulsion droplet size after redispersion. Results from redispersion experiments are combined with previously presented knowledge about powder surface composition and particle structure to elucidate internal processes in the powder matrix and external processes on the powder surface during drying and storage of whey protein powder. The results show that with addition of lactose to whey protein-stabilized emulsions, emulsion droplet structure remains intact in the powder matrix during drying since the emulsion droplet size in the redispersed spray dried emulsion is unchanged. In the absence of lactose there is a growth in emulsion droplet size after redispersion of the spray-dried whey protein-stabilized emulsion, showing that a coalescense of emulsion droplets occurs during the drying or redispersion process. Storage of the whey protein-stabilized powders in a humid atmosphere (relative humidity 75%, 4 days) induces changes in some powders. When the powder contains a critical amount of lactose there is a remarkable increase in emulsion droplet size after redispersion of humid stored powders compared with the emulsion before drying and with the redispersed dry stored powder. In addition, there is a release of encapsulated fat after humid storage of lactose-containing powders detected by electron spectroscopy for chemical analysis. For powders which do not contain any lactose there is no increase in emulsion droplet size after storage in a humid atmosphere compared with the redispersed dry stored emulsion. Addition of only a small amount of lactose prevents coalescence of emulsion droplets and the subsequent increase in droplet size during drying. If the lactose content is kept rather low neither an effect on the droplet size after storage under humid conditions nor a release of fat onto powder surfaces is detected. Furthermore, wettability of the spray-dried whey protein-stabilized emulsions by water is presented. It is concluded that it is beneficial to wettability in water to have as high a coverage of lactose on the powder surface as possible. In addition, a review of particle structure for powders of various composition is presented.     

Preparation and characterization of sericin powder extracted from silk industry wastewater

In this study, we developed a new effective technology for the extraction of sericin from silk wastewater. Sericin was extracted with 75% (v/v) ethanol to obtain crude powder. The chemical composition of sericin powder, including protein, sugar, ash, and amino acid, was assayed in detail. The molecular weight distribution of sericin was also investigated by gel filtration chromatography, sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), and high performance liquid chromatography (HPLC) analytical methods. The results suggested that sericin represented a family of proteins with wide-ranging molecular weight distribution. The conformation changed in the course of ethanol precipitation was studied by circular dichroism (CD) analysis. Data implied that the major conformation of sericin protein was random coil, which decreased slightly after being treated with ethanol, and the appearance of β-Turn conformation maybe associated with the packing of molecular chains induced by ethanol. Furthermore, sericin was found to inhibit tyrosinase activity when chlorogenic acid was used as a substrate, and had obvious radical scavenging effects with the 2.2-diphenyl-1-picryl-hydrazil (DPPH) assay. Result suggested that sericin might be a valuable ingredient for food.     

Dairy powder rehydration: influence of protein state, incorporation mode, and agglomeration

A simplified method to study rehydration was used on different dairy powders. The method involved dispersing powder in a stirred vessel equipped with a turbidity sensor. The changes of turbidity occurring during powder rehydration highlighted the rehydration stage, and the influence of the proteins’ state on rehydration was clarified. Casein powders had a quick wetting time but very slow dispersion, making the total rehydration process time-consuming. On the other hand, whey powders were found to have poor wettability but demonstrated immediate dispersion after wetting. Mixing casein (80%) and whey (20%) before spray drying greatly improved rehydration time compared with casein powder; whereas mixing whey powder with casein powder at the same ratio after spray drying caused a dramatic deterioration in the rehydration properties. Moreover, agglomeration was found to significantly improve the rehydration time of whey protein powder and to slow down the rehydration time of casein powder. These opposite effects were related to the rate-controlling stage (i.e., wetting stage for whey protein and dispersion stage for casein).     

干燥温度对丝胶膜结构的影响

以茧层丝胶为原料,干燥温度作为主要条件制备丝胶膜,用X射线衍射、红外光谱、DTA差热分析等测试方法研究干燥温度对丝胶膜结构的影响。实验结果表明:在30~100℃温度范围内,干燥温度对丝胶蛋白质的聚集态结构有显著影响。30℃干燥后膜内的丝胶聚集态结构基本为无定形,随着干燥温度的提高,膜内丝胶蛋白聚集态结构的紧密度增大,80℃以上增加明显。40℃左右是丝胶蛋白发生显著变性的重要温度区域。     

真空冷冻与喷雾干燥对鸡蛋全蛋粉理化性质及超微结构的影响

本文以鲜蛋为原料,目的是比较两种干燥方式对全蛋粉的理化性质和功能性质的影响。采用的方法是使用喷雾干燥与真空冷冻干燥两种干燥方式制备全蛋粉并对干燥后得到的全蛋粉的理化性质和功能性质进行了对比研究,探讨了两种干燥方式对全蛋粉的水分含量,水分活度,颗粒分布情况,溶解度,起泡性,乳化性的影响。同时分析比较了两种干燥方式制备的全蛋粉的微观结构图。结果表明,两种干燥方式制成的全蛋粉水分含量和水分活度差异不显著(p0.05),冷冻干燥全蛋粉的溶解度为93.32%,喷雾干燥全蛋粉溶解度87.88%,真空冷冻干燥全蛋粉的乳化活性和起泡力的最大值分别为0.338,62.6%,喷雾干燥全蛋粉的乳化活性和起泡力的最大值为0.248,53.4%。数据表明真空冷冻干燥制成的全蛋粉功能性质优于冷冻干燥制成的全蛋粉。而两种干燥方式制成的全蛋粉的颗粒分布情况与微观结构表征也存在显著差异。     

Effect of drying methods on the physical properties and microstructures of mango (Philippine ‘Carabao’ var.) powder

Mango powders were obtained at water content below 0.05 kg water/kg dry solids using Refractance Window® (RW) drying, freeze drying (FD), drum drying (DD), and spray drying (SD). The spray-dried powder was produced with the aid of maltodextrin (DE = 10). The chosen drying methods provided wide variations in residence time, from seconds (in SD) to over 30 h (in FD), and in product temperatures, from 20 °C (in FD) to 105 °C (in DD). The colors of RW-dried mango powder and reconstituted mango puree were comparable to the freeze-dried products, but were significantly different from drum-dried (darker), and spray-dried (lighter) counterparts. The bulk densities of drum and RW-dried mango powders were higher than freeze-dried and spray-dried powders. There were no significant differences (P ? 0.05) between RW and freeze-dried powders in terms of solubility and hygroscopicity. The glass transition temperature of RW-, freeze-, drum- and spray-dried mango powders were not significantly different (P ? 0.05). The dried powders exhibited amorphous structures as evidenced by the X-ray diffractograms. The microstructure of RW-dried mango powder was smooth and flaky with uniform thickness. Particles of freeze-dried mango powder were more porous compared to the other three products. Drum-dried material exhibited irregular morphology with sharp edges, while spray-dried mango powder had a spherical shape. The study concludes that RW drying can produce mango powder with quality comparable to that obtained via freeze drying, and better than the drum and spray-dried mango powders.