Flavonoid microparticles by spray-drying: Influence of enhancers of the dissolution rate on properties and stability

Naringenin (Nn) and Quercetin (Q) have numerous health benefits particularly due to their antioxidant properties. However, their low solubility, bioavailability and stability limit their use as components for functional foods, nutraceuticals and pharmaceutical agents. In this research, Nn- and Q-microparticles were produced by a spray-drying process using a combination of cellulose acetate phthalate (CAP) as coating gastroresistant polymer and swelling or surfactant agents as enhancers of dissolution rate. Raw materials and microparticles produced were all characterized by particle size analysis, differential scanning calorimetry, X-ray diffraction, and imaged by electron and fluorescence microscopy. During 12 months, storage stability was evaluated by analyzing drug content, HPLC and DSC profiles, as well as antioxidant activity (DPPH test). In vitro dissolution tests, using a pH-change method, were carried out to investigate the influence of formulative parameters on flavonoid release from the microparticles. Presence of a combination of CAP and surfactants or swelling agents in the formulations produced microparticles with good resistance at low pH of the gastric fluid and complete flavonoid release in the intestinal environment. The spray-drying technique and the process conditions selected have given satisfying encapsulation efficiency and product yield. The microencapsulation have improved the technological characteristics of the powders such as morphology and size, have given long-lasting storage stability and have preserved the antioxidant properties.     

木葡糖酸醋杆菌发酵黄酒糟酶解液产细菌纤维素的研究

该研究利用单因素比较法,分别考察了培养基组成、培养条件及黄酒糟酶解条件对木葡糖酸醋杆菌（Gluconacetobacter xylinus）发酵产细菌纤维素的影响。结果表明,木葡糖酸醋杆菌BC19-2产细菌纤维素的培养基组成为黄酒糟酶解液6%、红茶2 g/100 mL;培养条件为初始pH 6.0、培养温度30℃、接种量6%;黄酒糟酶解条件为酶解时间3 h,黄酒糟酶解液体积分数90%。在此优化条件下,细菌纤维素产量最高为26.5 g/L,且性能较好,为低成本的细菌纤维素生产奠定了基础。     

水酶法提取花生蛋白工艺的研究

采用水酶法从花生中提取蛋白质,筛选了三种酶制剂,确定选用纤维素酶作为水解酶;得出纤维素酶提取花生蛋白的最佳条件为:碱浸提液pH7.5,浸提温度45℃,酶用量0.2g/L,反应时间120min,酸沉pH4.5;在此条件下花生蛋白的得率为69.59%,蛋白质含量为91.88%。     

Influence of cider‐making process parameters on the odourant volatile composition of hard ciders

This study was performed to explore the relationships between some parameters of the French cider‐making process and the odourant compounds of cider. Sixteen ciders were prepared on a pilot plant scale using experimental design and varying according to apple blends, pressing conditions, pre‐fermentation clarification implementation and conditions, and biomass reduction during fermentation. Odourant compounds were extracted from final ciders by headspace solid‐phase microextraction with a CAR/PDMS fibre, a method previously shown to provide extracts representative of the studied cider. Extracts were analysed by gas chromatography coupled with mass spectrometry and flame ionization detection. All of the parameters tested had at least a slight effect on the odourant composition and particularly on the esters, which bring fruity notes that are appreciated by consumers. Clarification and biomass reduction had a greater impact than apple blend and pressing conditions. This could be explained by the influence of the nitrogen content on fermentation rate and efficiency, which affects the production of secondary metabolites. Under the conditions tested, a juice obtained from a bitter blend of apples by a slow pressing of the pulp at low temperature, after 1 h of cuvage, clarified by keeving and fermented without biomass reduction, produced a cider with the highest quantity of esters. These results could help cider‐makers enhance product quality according to consumer expectations. Copyright © 2015 The Institute of Brewing & Distilling     

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.     

An Alternative Strategy to Obtain Cellulose Nanofibrils from Parenchyma Cellulose of Bagasse Pith and the Performance of Its Nanopaper

Cellulose nanofibrils (CNFs) were obtained through one-step mechano-partial dissolution by ball milling in N, N-dimethyl acetamide with a low concentration of LiCl from agricultural waste bagasse pith (BP). Compared with fibrous cellulose, parenchyma cellulose (PC) is less uniform in diameter and less aligned, causing PC to dissociate into CNFs during this process without pretreatment. The results showed that the CNFs prepared from PC of BP had a diameter of 30-200 nm and a length of several micrometers. The as-obtained CNFs, along with dissolved cellulose, formed a wet-stable and highly transparent nanopaper in a sorbitol aqueous solution bath, which exhibited a high strain of 101% and a low Young''s modulus of 4.3 MPa owing to the addition of the plasticizer sorbitol. This type of nanopaper with favorable transparency, high tensile property, and low Young''s modulus has great potential for use as electronic skin and medical dressing material.     

Description of transport mechanism during the elimination of copper(II) from wastewaters using supported liquid membranes and Acorga M5640 as carrier

The kinetics of copper facilitated transport through a flat-sheet supported liquid membrane is investigated, using the commercially available oxime Acorga M5640 as ionophore, as a function of hydrodynamic conditions, stripping phase composition, concentration of copper(II), and pH of the source phase and carrier concentration in the membrane phase. The performance of the system is also compared using organic diluents of different nature (aliphatic or aromatic) and against other available oxime extractants (LIX 860, LIX 622, LIX 973N and LIX 84-I). A model is presented that describes the transport mechanism, consisting of diffusion through source side aqueous diffusion layer, a fast interfacial chemical reaction, and diffusion carrier and its metal complex through the organic membrane. The organic membrane diffusional resistance (delta(org)) and aqueous diffusional resistances (delta(aq)) were calculated from the proposed model, and their values were 9.3 x 10(-7) and 46565 s/cm, respectively. It was observed that the copper flux across the membrane tends to reach a plateau at high concentration of copper or low concentration of H+ owing to carrier saturation within the membrane and leads to a diffusion-controlled process. The values of the apparent diffusion coefficient (Dorg(a)) and limiting metal flux (Jlim) were calculated from the limiting conditions and found to be 5.2 x 10(-11) and 1.9 x 10(-9) mmol/cm2 s, respectively. The values of the bulk diffusion coefficient (Db,org) and diffusion coefficient (Dorg) calculated from the model were 4.8 x 10(-10) and 1.3 x 10(-10) cm2/s,respectively. The method had proven its feasibility to recover copper(II) from wastewaters.     

混合酶法降解玉米芯生产低醇保健饮料的研究

以玉米芯为原料,通过纤维素酶、纤维二糖酶降解获得酶解液,酵母菌发酵酶解液生产低醇保健饮料。采用正交试验,通过测定酶解时还原糖转化率和感官评价低醇保健饮料确定最佳条件。研究结果表明:纤维素酶与纤维二糖酶混合降解玉米芯的最佳条件:纤维素酶与纤维二糖酶比例为2∶1,混合酶添加量为0.4%,酶解时间为5h,酶解温度为45℃,在此条件下玉米芯的还原糖转化率为67.78%。发酵玉米芯酶解液生产低醇保健饮料的最佳条件为:酵母菌接种量为5%,发酵时间为36h,发酵温度为32℃。在最佳条件下,发酵产品均匀一致,呈淡黄色,有浓郁的玉米香,滋味柔和,感官评价得分为94分。     

亚麻废纱制备的纤维素基高吸水保水树脂及其性能

为了解决目前麻纺工业废料后续处理及环境污染问题,以麻纺企业废弃的亚麻纱线为原料,进行化学脱胶获取纤维素,采用非均相聚合体系,以纤维素为基质接枝丙烯酸单体制备高吸水保水树脂。采用单因素实验针对制备体系的工艺条件进行优化,并对较优条件下制备的纤维素基高吸水保水树脂进行性能表征。结果表明：最优合成工艺为单体丙烯酸、引发剂过硫酸铵、交联剂N, N’-亚甲基双丙烯酰胺用量分别为5、0.1、0.04 g/g纤维素,反应温度70℃,反应时间3 h;合成高吸水保水树脂在去离子水、自来水和0.9 wt%盐水中吸水倍率分别为658 g/g、382 g/g和65 g/g;室温（25℃）下自然风干12 d,保水率为74.3 %,鼓风干燥箱内30℃放置10 h,保水率为81.2 %,60 ℃放置10 h,保水率为26.4 %。说明制备的亚麻纤维素基高吸水保水树脂具有良好的吸水保水性能,可广泛应用于在农林、园艺等实际生产领域。     

香蕉皮制备羧甲基纤维素

以香蕉皮为原料,氢氧化钠为催化剂,氯乙酸为醚化剂,制备了羧甲基纤维素。考察了NaOH用量、醚化时间、醚化温度、碱化时间、乙醇用量对羧甲基纤维素取代度的影响。通过PB筛选,确定NaOH用量、氯乙酸用量和醚化温度为继续优化的影响因素。在单因素实验基础上,采用响应面法进一步优化了制备羧甲基纤维素工艺参数。结果表明,制备羧甲基纤维素的最佳工艺参数为:m(纤维素):m(NaOH)=1:1.5 (g·g-1)、m(纤维素):m(氯乙酸)=1:1.9 (g·g-1)、醚化温度80 ℃。羧甲基纤维素取代度的平均值为1.23。通过红外光谱分析可知羧甲基纤维素制备完成。     

响应面法优化灰绿青霉Penicillium glaucum NS16产酶条件

采用响应面法对灰绿青霉Penicillium glaucum NS16生产纤维素酶的发酵条件进行了优化,通过Plackett-Burman实验方法研究有关碳源、氮源、无机盐、发酵时间、摇床转速等18个发酵因子对菌株发酵产纤维素酶活力的影响.结果显示,影响产酶的显著因子是麸皮、CMC的含量和发酵时间.根据实验结果和经验方法对显著影响因子的取值范围进行预估,并采用Box-Behnken设计实验进行优化,然后应用响应面模拟预测和摇瓶发酵实验验证,结果表明,优化发酵条件为培养基中麸皮6.0 g/L,CMC 7.0 g/L,发酵时间96 h,摇瓶发酵液中CMC酶活均接近309 IU/mL,优化预测值和实验验证值拟合度达到99%,比初始培养基和发酵条件下菌株产CMC酶活94.51 IU/mL提高了227%.     

Naßklassierung von Stärke — eine physikalische Beeinflussungsmöglichkeit der technologisch wichtigen Eigenschaften von Stärke

Wet Classification of Starch — a physical possibility to influence the technologically important properties of starch . The requirements on the sharp classification of starch are not totally fulfilled by known methods. A classification process was developed by counter-current separation in the centrifugal field. With this technique, narrow starch grain size distributions can be produced. These product fractions are different in thier grain size, viscous properties, their composition (ash, protein, grease) and other relevant starch qualities. The grain size at which the separation is carried out can be changed by a variation of the operating parameters (through-put and centrifugal field of the centrifuge) and determined by means of a given equation. The quality of the classification process depends on the starch properties (starch and protein contents in the suspension) and operating parameters (water through-put). A typical result of the classification (coarse fraction: 3%< 10μm; fine fraction: 70%< 10μm) is presented. But also the influence of the operating parameters on the separation efficiency curve and the properties of the product fractions are discussed.     

Raw and Processed Oat Ingredients Lower Plasma Cholesterol in the Hamster

The objective of this study was to determine if Oatrim, a product developed for use as a fat substitute, could also reduce plasma cholesterol due to its soluble dietary fiber content. Diets with soluble fiber contents of 0% (oat hydrolyzate) or 4.2–4.3%β-glucan from oat or Oatrim were fed to hamsters for 21 days. All oat derived diets reduced serum cholesterol compared to a control diet containing cellulose (p≥0.05). The available carbohydrate produced by the Oatrim process correlated inversely (r²0.95) with low density lipoproteincholesterol concentration.     

Electricity production from cellulose in a microbial fuel cell using a defined binary culture

Microbial fuel cells (MFCs) convert biodegradable materials into electricity, potentially contributing to an array of renewable energy production strategies tailored for specific applications. Since there are no known microorganisms that can both metabolize cellulose and transfer electrons to solid extracellular substrates, the conversion of cellulosic biomass to electricity requires a syntrophic microbial community that uses an insoluble electron donor (cellulose) and electron acceptor (anode). Electricity was generated from cellulose in an MFC using a defined coculture of the cellulolytic fermenter Clostridium cellulolyticum and the electrochemically active Geobacter sulfurreducens. In fed-batch tests using two-chamber MFCs with ferricyanide as the catholyte, the coculture achieved maximum power densities of 143 mW/ m2 (anode area) and 59.2 mW/m2 from 1 g/L carboxymethyl cellulose (CMC) and MN301 cellulose, respectively. Neither pure culture alone produced electricity from these substrates. The coculture increased CMC degradation from 42% to 64% compared to a pure C. cellulolyticum culture. COD removal using CMC and MN301 was 38 and 27%, respectively, with corresponding Coulombic efficiencies of 47 and 39%. Hydrogen, acetate, and ethanol were the main residual metabolites of the binary culture. Cellulose conversion to electricity was also demonstrated using an uncharacterized mixed culture from activated sludge with an aerobic aqueous cathode.     

Potential of a nisin-containing bacterial cellulose film to inhibit Listeria monocytogenes on processed meats

A bacterially produced cellulose film containing nisin was developed and used in a proof-of-concept study to control Listeria monocytogenes and total aerobic bacteria on the surface of vacuum-packaged frankfurters. Bacterial cellulose pellicles were produced by Gluconacetobacter xylinus K3 in Corn Steep Liquor-Mannitol Medium and were subsequently purified before nisin was incorporated into them. Investigations into the effect of nisin concentrations and contact times on incorporation of nisin into cellulose films showed that the lowest nisin concentration and shortest time needed for production of an effective antimicrobial cellulose film were 625IUml(-1) and 6h, respectively. The active cellulose films produced under these conditions did not, however, significantly reduce L. monocytogenes populations on frankfurters (P>0.05) during refrigerated storage for 14 days as compared to the controls. Films produced using a higher concentration of nisin (2500IUml(-1)) with the same exposure time (6h) resulted in a significant (P<0.05) decrease in L. monocytogenes counts on frankfurters of approximately 2logCFUg(-1) after 14 days of storage as compared to the control. Both the above-mentioned films showed a similar effectiveness in reducing total aerobic bacterial populations as measured by total aerobic plate counts on frankfurters. For both films, total aerobic bacterial levels were significantly (P>0.05) reduced by approximately 3.3logCFUg(-1) after 14 days of storage as compared to control samples. Bacterial cellulose films were demonstrated in this study to have potential applicability as antimicrobial packaging films or inserts for processed meat products.     

Influence of manufacturing conditions on the conjugated linoleic acid content and the isomer composition in ripened French Emmental cheese

In a study of the evolution of conjugated linoleic acid (CLA) during cheese production, the influence of Emmental cheese processing on the CLA content and the CLA isomer composition was evaluated. The use of raw and thermised milk, changes of processing temperature and the effect of propionic acid bacteria (PAB) were investigated. The content of CLA in raw milk was 8.6 +/- 1.9 mg/g fat and in the ripened cheese at 70 d was 8.6 +/- 1.6 mg/g fat, under normal processing conditions. No changes in the CLA content and CLA isomer composition were observed during Emmental cheese manufacturing process. Changes in cooking and moulding temperatures did not influence the CLA content. CLA content of cheese made from microfiltered milk with two different Propionibacterium freudenreichii strains was very close to cheeses made without PAB. CLA levels seem to be stable in this type of dairy product under the conditions examined.     

Energy efficient production of hydrogen and syngas from biomass: development of low-temperature catalytic process for cellulose gasification

The Rh/CeO2/M (M = SiO2, Al2O3, and ZrO2) type catalysts with various compositions have been prepared and investigated in the gasification of cellulose, a model compound of biomass, in a fluidized bed reactor at 500-700 degrees C. The conventional nickel and dolomite catalysts have also been investigated. Among the catalysts, Rh/CeO2/SiO2 with 35% CeO2 has been found to be the best catalyst with respect to the carbon conversion to gas and product distribution. The steam addition contributed to the complete conversion of cellulose to gas even at 600 degrees C. Lower steam supply gave the syngas and higher steam supply gave the hydrogen as the major product. Hydrogen and syngas from cellulose or cellulosic biomass gasification are environmentally super clean gaseous fuels for power generation. Moreover, the syngas derived liquid fuels such as methanol, dimethyl ether, and synthetic diesels are also super clean transportation fuels. However, the use of cellulose or cellulosic biomass for energy source through the gasification is challenging because of the formation of tar and char during the gasification process. It is interesting that no tar or char was finally formed in the effluent gas at as low as 500-600 degrees C using Rh/CeO2/SiO2(35) catalyst in this process.     

长余辉发光再生纤维素纤维的制备

对稀土铝酸锶长余辉粉末采用硅烷偶联剂进行包覆处理,增强了稀土铝酸锶粉末在水性溶液中的稳定性。以包覆处理过的稀土铝酸锶粉末为添加剂,以新型碱体系制备的再生纤维素为基材,通过湿法纺丝,制备出长余辉发光再生纤维素纤维。借助傅里叶红外光谱仪、扫描电镜、X射线衍射仪、单纤维强力测试仪、余辉亮度测试仪对样品的性能进行表征,结果表明:偶联剂通过化学键Si—O—Al包覆在稀土铝酸锶粉末上;经过偶联剂处理后,发光纤维的外观形貌较为光滑,直径约为60μm;纤维中稀土铝酸锶结构和纤维素Ⅱ结构同时出现,二者没有相互影响;纤维力学强度提高了10%;余辉初始亮度为0.82 cd/m~2。     

Effect of processing conditions and composition on sodium caseinate emulsions stability

Many food products such as ice cream, yoghurt, and mayonnaise are some examples of emulsion-based food. The physicochemical properties of emulsions play an important role in food systems as they directly contribute to texture, sensory and nutritional properties of food. One of the main properties is stability which refers to the ability of an emulsion to resist physical changes over time. The aim of the present work was to analyze the effect of processing conditions and composition on sodium caseinate (NaCas) emulsions stability. The main destabilization mechanisms were identified and quantified. The relationship between them and the factors that influence them were also investigated. Emulsions stabilized with NaCas were prepared using an ultrasound liquid processor or a high pressure homogenizer. Stability of emulsions was followed by a Turbiscan (TMA 2000) which allows the optical characterization of any type of dispersion. The physical evolution of this process is followed without disturbing the original system and with good accuracy and reproducibility. To further describe systems, droplet size distribution was analyzed with light scattering equipment. The main mechanism of destabilization in a given formulation depended on different factors such as NaCas concentration, droplet size or processing conditions. The rate of destabilization was markedly lower with addition of sugar or a hydrocolloid to the aqueous phase. Xanthan (XG) and locust bean (LBG) gums produced an increase in viscosity of the continuous phase and structural changes in emulsions such as gelation. Sugars interacted with the protein decreasing particle size and increasing emulsion stability. The stability of caseinate emulsions was strongly affected not only by the oil-to-protein ratio but also by processing conditions and composition of aqueous phase. The structure of the protein and the interactions protein–sugar or the presence of a hydrocolloid played a key role in creaming and flocculation processes of these emulsions.     

Kinetics of L-tryptophan production from indole and L-serine catalyzed by whole cells with tryptophanase activity

The essential amino acid L-tryptophan can be produced by a condensation reaction between indole and L-serine, catalyzed by whole cells of Escherichia coli B1t-7A with tryptophanase activity. The reaction was previously studied using soluble tryptophanase, a kinetic mechanism proposed and the catalytic properties of the enzyme described. It is important, however, to determine the kinetic parameters of the reaction catalyzed by whole cells, if the process is to be designed with the catalyst in this form. The reaction stoichiometry was established, a mole of product being formed from a mole of each reactant, with no indication of side reactions under the conditions used. The two-substrate reaction kinetics were characterized and modelled, assuming an enzyme-substituted mechanism and no product inhibition. Theoretical consumption rates of indole were compared with experimental values obtained in a batch reactor system. The K(m) values of whole cells towards L-serine and indole were 1.79 M and 0.07 M, respectively. These values are, as expected, considerably higher than their counterparts for soluble tryptophanase.