胶原蛋白/羧甲基纤维素(CMC)膜的制备及其力学性能研究

从废皮屑中提取胶原蛋白,与羧甲基纤维素(CMC)和甘油共混制成复合膜,并对复合膜力学性能的影响因素进行了研究。结果表明:在共混体系中加入一定的羧甲基纤维素,有利于提高膜的强度;将羧甲基纤维素加入膜体系后,膜的力学性能有了显著提高。在羧甲基纤维素与胶原蛋白质量比1∶2,羧甲基纤维素质量分数4%,胶原蛋白质量分数12%,膜液pH值为3.5,溶液温度60℃,溶液共混时间60min,甘油质量分数3%条件下,制得的共混膜力学性能最佳。     

柠檬果渣果胶提取工艺研究

研究以柠檬果渣为主要原料提取果胶的最佳工艺条件,采用微波辅助酸法提取柠檬果胶。通过单因素试验研究萃取剂、微波加热时间、加热功率、pH及料液比对果胶提取率的影响。再通过正交试验进一步优化提取条件,得出影响果胶提取率的因素的主次顺序为微波加热时间＞pH＞微波加热功率＞料液比。最终确定了提取果胶的最佳工艺为选用盐酸溶液作为萃取剂,微波加热时间2 min,pH值为2.0,微波加热功率480 W,料液比1∶30（g∶mL）,其提取率为27.96%。     

纤维素氨基甲酸酯纤维纺丝工艺探讨

通过研究纤维素氨基甲酸酯(CC)溶液中CC与NaOH配比(质量比)、溶液纺前处理时间及温度、纺丝凝固浴及再生浴的组成和温度对纤维素氨基甲酸酯溶液可纺性及其纤维性能的影响,得到湿纺工艺制备纤维素氨基甲酸酯纤维的最佳纺丝工艺条件.结果表明:配制CC质量分数为7%,CC与NaOH质量比为1的纤维素氨基甲酸酯的氢氧化钠溶液,在15℃以下进行纺前处理10～12 h,溶液可纺性良好.这种溶液在温度为加℃的含H2SO4(150 g/L)、Na2So4(200 g/L)、Al2(SO4),(50 g/L)的凝固浴中成形后,在温度为85℃、质量分数为1%的氢氧化钠水溶液中再生,可得到具有一定强度及伸长率的再生纤维素纤维.     

纤维素LiCl/DMAc溶液的制备及溶液稳定性

 研究了制备纤维素LiCl/DMAc（氯化锂/N,N-二甲基乙酰胺）溶液的制备工艺及溶液稳定性。结果表明：将活化处理的纤维素加入到LiCl溶解在DMAc形成的LiCl/DMAc体系中,在100℃下搅拌一定时间后冷却到室温搅拌数小时,可得到均匀透明的纤维素LiCl/DMAc溶液。配制该溶液,纤维素浓度越大, 所需加热搅拌和室温搅拌时间越长;同样,纤维素聚合度越大,其溶解效果越差;LiCl含有结晶水,纤维素只溶胀不溶解,而且只当LiCl质量分数超过6%时, 纤维素才能完全溶解,LiCl含量随纤维素浓度而提高。另外,通过研究纤维素LiCl/DMAc溶液在不同温度下的粘度随时间的变化率,得出了在低于50℃下,该溶液在30天内很稳定;溶液加热至100℃后,可稳定存在15小时的结论。     

竹溶解浆的碱预处理及其溶解性能研究

选用聚合度为1228的商品竹溶解浆为原料,通过偏光显微镜、纤维素溶液紫外-可见光（UV-Vis）光谱、动态光散射（DLS）和透射电镜（TEM）分析及溶解率测定研究了经不同浓度NaOH（质量分数1%～12%）预处理后的竹溶解浆在7%NaOH/12%尿素水溶液溶剂体系中的低温溶解行为。结果表明,适宜浓度碱液的预处理提高了纤维素的反应活性及7%NaOH/12%尿素水溶液溶剂对竹溶解浆纤维素的可及度,其中,9% NaOH预处理后的竹溶解浆表现出最佳的溶解效果。     

影响NMMO纤维素溶液流变性的因素

研究了体系温度、剪切速率、纤维素质量分数和不同聚合度配比等因素与纤维素/NMMO溶液流变性的关系,尤其是通过聚合度配比这一方法更准确地探讨了聚合度大小对纤维素溶液表观黏度的影响。研究结果表明:浓度为4%的纤维素/NMMO·H2O溶液体系其ΔEη为24.45k J/mo L。不同聚合度的纤维素溶液都属于假塑性流体,存在剪切变稀现象,高聚合度纤维素溶液的剪切变稀现象比低聚合度的更明显。相同浓度但不同聚合度配比条件下,溶液黏度增加与纤维素聚合度增加大致呈比例,但是配比为1∶1的纤维素溶液例外。     

咖啡果壳微晶纤维素制备及其吸附性能研究

目的：利用咖啡果壳制备高吸附能力微晶纤维素。方法：用酸解法制备咖啡果壳微晶纤维素,考察酸解时间、酸解温度、盐酸质量分数和料液比对微晶纤维素得率和吸附能力的影响。结果：咖啡果壳微晶纤维素的最佳制备工艺为酸解时间95 min,盐酸质量分数16%,料液比（m_{咖啡果壳纤维素}∶V_酸）1∶22 （g/mL）,酸解温度60 ℃,该工艺条件下咖啡果壳微晶纤维素得率为80.08%,对香精的吸附能力为0.89 g/g。结论：料液比对咖啡果壳微晶纤维素得率影响最大,酸解温度对其吸附能力影响最大,优化工艺得到的咖啡果壳微晶纤维素得率高,吸附能力强。     

半纤维素-甲基纤维素复合膜的制备及其性能分析

将甲基纤维素和山梨醇分别添加到半纤维素中制备半纤维素-甲基纤维素复合膜及半纤维素-山梨醇复合膜,对复合膜的成膜性和强度性能进行分析,并探讨半纤维素-甲基纤维素及半纤维素-山梨醇混合溶液的粒径和Zeta电位。结果表明,随着甲基纤维素质量分数增加,半纤维素-甲基纤维素混合溶液粒径先增大后减小;Zeta电位则随着甲基纤维素质量分数的增加先降低后提高,甲基纤维素质量分数为75%时,半纤维素-甲基纤维素混合溶液的Zeta电位达到最小值。当甲基纤维素质量分数为35%时,可形成完整的半纤维素-甲基纤维素复合膜,增加甲基纤维素质量分数,复合膜强度提高;当甲基纤维素质量分数为75%时,复合膜强度最大,但继续增加甲基纤维素的质量分数,复合膜强度降低。山梨醇质量分数为35%～50%时,可形成完整的半纤维素-山梨醇复合膜,且随着山梨醇质量分数增加,复合膜强度降低。     

紫薯花青素提取条件优化及淀粉等产物的制备

以‘紫罗兰’紫薯为原料,研究同步提取紫薯花青素以及制备紫薯淀粉、纤维素和紫薯蛋白的工艺及参数。紫薯与酸乙醇（pH 2）混合破碎、过滤、沉淀分离淀粉;将滤渣和分离淀粉后上清液混合,用微波辅助法提取花青素并优化提取条件;花青素提取液沉淀分离紫薯蛋白;提取花青素的滤渣制备紫薯纤维素。结果表明：微波辅助提取紫薯中花青素的最佳工艺条件为微波时间4 min、微波温度52 ℃、料液比1∶22.40（g/mL）、乙醇体积分数62%（pH 2）,在此条件下紫薯花青素的提取率（93.64±0.69）%、粗提物中花青素含量（9.58±0.20） mg/g。制备的紫薯淀粉质量分数（95.77±0.41）%、得率（占总淀粉质量分数）（73.06±1.03）%;滤渣粉中纤维素含量（117.11±2.69） mg/g;制备的紫薯蛋白中蛋白质含量（524.78±24.84） mg/g。该制备方法能够提高紫薯的利用率,降低生产成本。     

芦苇乙二醇制浆的研究

在常压下,利用低浓度的乙二醇溶液蒸煮芦苇,分别做了酸用量、液固比和有机溶剂浓度实验.研究结果表明:乙二醇在常压下表现出良好的纤维素、木质素分离趋势,在乙二醇40%、催化剂10%、水50%、酸3%和液固比20:1时,纤维素、木质素分离效果最佳,浆的质量较好;乙二醇通过蒸馏回收可以循环利用,并可得到较纯的木质素.     

脱色吸附剂对大豆脱色油返酸返色的影响

为对油脂精炼脱色加工提供参考,以活性白土、凹凸棒土以及二者复配作为脱色剂对大豆中和油进行脱色,测定脱色油的酸值、色泽,并通过返酸返色试验探究脱色吸附剂对大豆脱色油返酸返色的影响。结果表明：脱色油酸值与活性白土添加量和复配脱色剂中活性白土质量分数呈正相关,与凹凸棒土添加量呈负相关;脱色剂添加量越多,脱色效果越明显,但在活性白土或凹凸棒土添加量超过3%时,脱色效果增加较少;随活性白土或凹凸棒土添加量的增多,脱色油返酸总体呈先降后升趋势;脱色油会有不同程度的返色,与活性白土相比,凹凸棒土脱色返色程度更高。综上,在脱色过程中,通过调整脱色剂添加量和配比可在一定程度上控制成品油的返酸返色程度。     

Effect of bleaching whey on sensory and functional properties of 80% whey protein concentrate

Whey is a highly functional food that has found widespread use in a variety of food and beverage applications. A large amount of the whey proteins produced in the United States is derived from annatto-colored Cheddar cheese. Color from annatto is undesirable in whey and must be bleached. The objective of this study was to compare 2 commercially approved bleaching agents, benzoyl peroxide (BP) and hydrogen peroxide (HP), and their effects on the flavor and functionality of 80% whey protein concentrate (WPC80). Colored and uncolored liquid wheys were bleached with BP or HP, and then ultrafiltered, diafiltered, and spray-dried; WPC80 from unbleached colored and uncolored Cheddar whey were manufactured as controls. All treatments were manufactured in triplicate. The WPC80 were then assessed by sensory, instrumental, functionality, color, and proximate analysis techniques. The HP-bleached WPC80 were higher in lipid oxidation compounds (specifically hexanal, heptanal, octanal, nonanal, decanal, dimethyl disulfide, and 1-octen-3-one) and had higher fatty and cardboard flavors compared with the other unbleached and BP-bleached WPC80. The WPC80 bleached with BP had lower norbixin concentrations compared with WPC80 bleached with HP. The WPC powders differed in Hunter color values (L, a, b), with bleached powders being more white, less red, and less yellow than unbleached powders. Bleaching with BP under the conditions used in this study resulted in larger reductions in yellowness of the powders made from whey with annatto color than did bleaching with HP. Functionality testing demonstrated that whey bleached with HP treatments had more soluble protein after 10 min of heating at 90°C at pH 4.6 and pH 7 than the no-bleach and BP treatments, regardless of additional color. Overall, HP bleaching caused more lipid oxidation products and subsequent off-flavors compared with BP bleaching. However, heat stability of WPC80 was enhanced by HP bleaching compared with control or BP-bleached WPC80.     

红麻皮硫酸盐浆的高白度无氯漂白

对红麻皮ＫＰ浆常规多段漂白及无氯多段漂白工艺与机理进行了对比研究。采用ＣＥＨＰ漂白，总用氯量４．９％，Ｈ２Ｏ２用量０．５％，可漂至８７．１％白度。采用ＺＥｐＺＰ无氯漂白，Ｚ漂白浓度在５０％为最佳，Ｏ３总用量１．７％，Ｈ２Ｏ２总用量１．５％，可漂至８７．２％白度，虽然纸浆粘度比前者低１２．６％，但其强度还略优于前者。ＩＲ分析表明：臭氧漂白引起纤维素结晶指数的降低比常规漂白大。ＦＴ－ＩＲ差谱分析证明了漂白过程中木素的溶出。     

含不同纤维素酶量的木聚糖酶对麦草浆性质的影响

选用了里氏木霉的含不同纤维素酶量的木聚糖酶对麦草浆进行漂前预处理，研究了木聚糖酶中含不同纤维素酶量对浆料性能、结晶度和形态结构的影响。结果表明，随着用于预处理的木聚糖酶中纤维素酶量的增加，浆料的结晶度下降，浆料表面和横断面的孔隙增多，在相同氯用量时漂白浆白度逐渐上升，裂断长和耐破指数逐渐下降。当木聚糖酶活与CMC酶活的比值大于121时，浆料的裂断长和耐破指数大于原浆。因此，木聚糖酶中少量纤维素酶的存在对提高漂白浆的白度有促进作用，但当纤维素酶量较多时对纸浆的强度和结晶度有损伤。     

变色柞木刨切薄木的漂白工艺研究

以双氧水为漂白主剂,利用不同的漂白配方对变色柞木刨切薄木进行漂白试验。在适宜的漂白温度下,以双氧水浓度、硅酸钠浓度、漂白时间为考查因素进行正交试验,并对漂白后柞木刨切薄木的色差和白度进行检测和分析,结果表明,优化漂白工艺为双氧水浓度3%,硅酸钠浓度0.7%,常温下漂白30min,浴比为10:1,漂白溶液pH值为10。     

氧碱蒸煮麦草浆的活化H2O2漂白

研究了活化H2O2漂白过程中药品用量、漂白时间、温度、漂液pH值以及2种活化剂——TAED(四乙酰乙二胺)和乙酸酐协同作用等因素对浆料白度的影响，结果表明，采用三段漂P1P2A，当P1段H2O2用量6％、TAED用量3％、乙酸酐用量5％，TAED在pH值为9．5左右加入(本实验中时间约为50min左右)；P2段H2O2用量4％、TAED用量2％、乙酸酐用量4％；A段H2SO3用量2％时，可获得较高的浆料白度(75．2％ISO)。漂白浆所测强度指标均与普通烧碱-AQ浆的CEH漂白浆相似。     

Microwave-Assisted Bleaching of Wool Fabrics

Microwave irradiation was used to reduce consumption of energy and time during bleaching of wool fabrics with hydrogen peroxide. The effect of some reaction conditions; viz. hydrogen peroxide concentration, treatment time, presence of stabilizer, on degree of whiteness imparted to bleached wool, was studied systematically. Comparative study between bleaching of wool using microwave irradiation and conventional heating was undergone. The effect of bleaching of wool on its morphological structure was assigned by scanning electron microscopy. The change in some chemical and physicomechanical characteristics of bleached wool was monitored; namely whiteness index, alkali solubility, wettability, critical surface area, tensile strength, and elongation at break, of the treated as well as untreated fabrics were measured. The microwave-assisted bleaching of wool resulted in improved degree of whiteness comparable to that is obtained using conventional heating method. However, the microwave-assisted bleached wool shows lower degree of deterioration than that of conventionally bleached wool. The COD and BOD of the wool bleaching effluents were determined.     

微波法制备阳离子纤维素工艺的研究

以漂白硫酸盐蔗渣浆和醚化剂3-氯-2-羟丙基三甲基氯化铵(CHPTMA)为原料,用微波作为加热方式合成阳离子纤维素,探讨了CHPTMA用量、NaOH用量、体系含水量、微波功率和微波时间等因素对产物取代度和Zeta电位的影响,确定了较优的合成条件:醚化剂与纤维素质量比0.45,NaOH与醚化剂质量比4.45,微波时间9 min,微波功率400W,体系含水量60％.此条件下制备的蔗渣阳离子纤维素的取代度可达0.192,Zeta电位为25.6 mV.通过红外光谱图分析证明,已经合成了具有阳离子官能团的纤维素.     

Influence of storage, heat treatment, and solids composition on the bleaching of whey with hydrogen peroxide

The residual annatto colorant in liquid whey is bleached to provide a desired neutral color in dried whey ingredients. This study evaluated the influence of starter culture, whey solids and composition, and spray drying on bleaching efficacy. Cheddar cheese whey with annatto was manufactured with starter culture or by addition of lactic acid and rennet. Pasteurized fat-separated whey was ultrafiltered (retentate) and spray dried to 34% whey protein concentrate (WPC34). Aliquots were bleached at 60 °C for 1 h (hydrogen peroxide, 250 ppm), before pasteurization, after pasteurization, after storage at 3 °C and after freezing at -20 °C. Aliquots of retentate were bleached analogously immediately and after storage at 3 or -20 °C. Freshly spray dried WPC34 was rehydrated to 9% (w/w) solids and bleached. In a final experiment, pasteurized fat-separated whey was ultrafiltered and spray dried to WPC34 and WPC80. The WPC34 and WPC80 retentates were diluted to 7 or 9% solids (w/w) and bleached at 50 °C for 1 h. Freshly spray-dried WPC34 and WPC80 were rehydrated to 9 or 12% solids and bleached. Bleaching efficacy was measured by extraction and quantification of norbixin. Each experiment was replicated 3 times. Starter culture, fat separation, or pasteurization did not impact bleaching efficacy (P > 0.05) while cold or frozen storage decreased bleaching efficacy (P < 0.05). Bleaching efficacy of 80% (w/w) protein liquid retentate was higher than liquid whey or 34% (w/w) protein liquid retentate (P < 0.05). Processing steps, particularly holding times and solids composition, influence bleaching efficacy of whey. PRACTICAL APPLICATION: Optimization of whey bleaching conditions is important to reduce the negative effects of bleaching on the flavor of dried whey ingredients. This study established that liquid storage and whey composition are critical processing points that influence bleaching efficacy.     

麦草浆不同漂白方法的研究

以烧碱-蒽醌麦草浆为原料,分别采用二氧化氯、氯和氧进行单段漂白,对不同方法的漂白效果进行分析比较。结果表明：传统的氯化效果最差,脱木素率及处理后的纸浆白度、黏度和成纸强度是3种方法中最低的;氧气虽然脱木素能力强、纸浆白度高,但纸浆黏度低,漂白过程对纤维的损伤也较严重;二氧化氯具有较好的选择性,不仅能够有效脱除木素,而且保持了较高的黏度和成纸强度。麦草原料纤维细小、木素含量较低,因而在确定漂白方案时,首段采用二氧化氯漂白比较适宜,才能尽量减少漂白中对纤维的降解,使纸浆获得较高的机械强度。