陶瓷复合膜澄清黑莓果酒工艺研究

利用陶瓷膜对黑莓果酒进行过滤澄清,考察不同孔径膜过滤澄清效果及果酒品质变化情况;并考察膜面流速、物料温度、操作压差等对过滤通量的影响,确定合适的过滤操作参数。结果表明:50nm孔径的陶瓷膜对黑莓果酒中蛋白质、可溶性固形物具有较好的截留作用,滤后果酒酒体清澈透明;在膜面流速为2.5m/s、物料温度为25℃、操作压差为0.3MPa的条件下可以获得较为理想的过滤通量。     

无机陶瓷膜澄清酱油的工艺研究

采用孔径为200nm、450nm、800nm的无机陶瓷膜过滤酱油,除去其中的大分子蛋白质及菌体,以澄清酱油消除二次沉淀现象。研究了不同孔径的无机陶瓷膜处理酱油,膜通量与过滤温度、过滤时间、操作压力及流速的关系,确定了选用200nm的陶瓷膜、操作温度在30℃、操作压力为0.20MPa过滤酱油可以解决酱油的二次沉淀现象,并可获得较高的膜通量。     

陶瓷膜在淀粉糖澄清工艺中的应用研究

该实验研究了陶瓷膜技术在淀粉糖澄清工艺中的应用。 结果表明,陶瓷膜可直接对混合糖化液进行过滤,50 nm孔径陶瓷膜 的澄清效果最佳,能够节约糖化时间超过12h。 设定操作压力为0.35 MPa,温度为70～80℃,设备的回流量为3.2m3/h,50 nm陶瓷膜 对糖化液浓缩33倍,平均通量为248.6 L（/ m2·h）,且通量保持稳定。陶瓷膜过滤后清液的蛋白去除率达75.9%,透射比提高至98.4%,均优于真空转鼓。陶瓷膜浓缩后的糖化液残渣经压滤和烘干,加工成蛋白饲料,每年为企业增收590万元,实现了淀粉糖的绿色节能生产。     

几种澄清方法对梨汁理化和感官等指标的影响

本文研究了无机陶瓷微滤膜微滤、中空纤维超滤以及果胶酶对梨汁的澄清效果、理化及感官指标的影响。采用三种孔径的氧化铝膜和自制的加压微滤装置、外购中空纤维超滤装置以及果胶酶进行澄清实验。实验结果表明:(1)0.2μm孔径无机陶瓷膜微滤对梨汁的可溶性固形物含量、VC含量和还原糖含量影响不大,澄清梨汁得率较高,并且基本保持了梨汁的原有风味,适合梨汁澄清生产。(2)50nm无机陶瓷膜微滤和中空纤维超滤因孔径太小,不适合梨汁澄清生产。(3)0.8μm孔径无机陶瓷膜微滤和果胶酶澄清处理梨汁的浊度太大,短时间出现分层或沉淀,不适合梨汁澄清生产。     

基于不同孔径陶瓷膜处理对泡菜汁品质影响的初步分析

该研究使用不同孔径(0.5,0.2,0.05,0.008μm)陶瓷膜处理泡菜汁,测定不同操作参数下不同孔径陶瓷膜处理泡菜汁微生物截留率、理化指标、有机酸含量、氨基酸含量及风味物质组成,分析了陶瓷膜处理对泡菜汁品质的影响。结果表明,0.008μm孔径膜过滤除菌效果比另外3种好。综合膜通量、理化指标和有机酸含量、氨基酸含量以及挥发性物质组成等多项指标评价,0.05μm孔径陶瓷膜效果最佳。实验确定的最佳过滤条件为:孔径0.05μm,操作压力0.35 MPa,过滤温度40℃,此时膜通量最大,为395 L/(m~2·h),微生物去除率达到99.1%,泡菜汁原有风味损失较低。     

无机陶瓷膜超滤澄清酱油的研究

用10、50、100nm孔径的无机陶瓷膜超滤酱油以除去其中的大分子蛋白质,澄清酱油以消除二次沉淀的现象。研究了不同孔径无机陶瓷膜超滤酱油,膜通量与超滤温度和超滤时间关系。选择用50nm孔径无机陶瓷膜管,在40℃左右超滤澄清酱油,可以解决酱油二次沉淀问题,并且稳定的超滤膜通量超过了100L/m2.h。碱液可以很好的清洗无机陶瓷膜管,恢复其超滤能力。     

小孔径陶瓷膜澄清甜叶菊提取液的工艺研究

该文研究了小孔径陶瓷膜澄清甜叶菊提取液的效果。通过比较4、5、8、10 nm孔径的陶瓷膜过滤甜叶菊的甜菊糖提取液时的过滤通量、脱色率和收率的区别,确定较优的陶瓷膜孔径;再优化陶瓷膜操作参数。结果表明,5 nm陶瓷膜较优,在40 ℃时,操作压力5 bar,膜面流速4 m/s,浓缩10倍,加30%原液体积水洗滤效果最佳,陶瓷膜平均过滤通量可达102.6 kg/（m2·h）,甜菊糖收率可达99.2%,陶瓷膜过滤结束后先利用质量分数1%~2%的NaOH清洗1 h,再用0.5%~1%硝酸清洗1 h,陶瓷膜水通量恢复率可以达到99%以上,再生效果比较好,可以重复使用。相比絮凝工艺,陶瓷膜脱色率提高了2.6%,甜菊糖收率提高了6.8%,因此膜法工艺可取代传统絮凝工艺实现对甜叶菊提取液的澄清。     

磷酸法澄清工艺研究初报

对用磷酸替代二氧化硫处理蔗汁的磷酸法澄清工艺进行了初步研究。试验结果表明:以澄清汁钙盐含量、纯度差、清净效率和非糖分除去率为表征的澄清效果,超过了亚硫酸法的,接近或达到了碳酸法的。认为,用该法替代亚硫酸法澄清蔗汁,经济、社会和环境的效益是显著的。     

MSF-HGMS对甘蔗混合汁清净效果的初步研究

研究了磁种和絮凝剂用量对磁种絮凝-高梯度磁分离(MSF-HGMS)用于澄清甘蔗混合汁清净效果的影响,确定了最佳用量.结果表明:在磁种用量50mg/L、絮凝剂用量3.5mg/L时,澄清效果最为明显,测量澄清汁平均结果为:色值2176.1IU、浊度253.7MAU、纯度80.0%和过滤速度17.64mL/min.     

甘蔗混合汁单宁无硫澄清脱色机理的研究

依次使用截留分子量为250、100、50 k Da的管式超滤膜来对甘蔗混合汁单宁无硫澄清工艺的一清汁进行过滤,再分别在一级截留液、二级截留液及三级透过液中加入单宁溶液、Ca(HCO3)2溶液及石灰乳进行二步澄清处理,分别检测二步澄清处理前后蔗汁色值,并使用全波长扫描技术分析蔗汁紫外吸收情况,分析单宁钙、Ca(CO3)2对蔗汁的不同分子量色素脱色效果;采用扫描电镜技术对纯水体系和蔗汁体系所生成的单宁钙与碳酸钙沉淀结构进行表征,研究其蔗汁澄清脱色机理。结果表明,单宁钙与碳酸钙可减少蔗汁中含有不饱和键致色物质含量和减少致色物质不饱和健数量,具有良好的脱色作用;单宁钙与碳酸钙晶体具有多孔隙结构,能很好地将蔗汁中有胶体、色素等非糖分吸附形成共沉淀,具有良好澄清效果。     

陶瓷膜和有机膜超滤处理荔枝汁和膜垢分析及荔枝汁品质研究

应用陶瓷膜和有机膜对荔枝汁进行澄清实验,并进行采用总循环模式(TRM)研究跨膜压力(TMP)和循环流量(Qf)对膜通量(Qp)的影响,确定其各自的最优水平;采用批处理模式(TBM)研究这两个参数最优水平的组合工艺。澄清工艺中：无机陶瓷膜效果优于有机聚醚砜膜,最佳工艺条件为陶瓷膜组件、TMP 0.3MPa、Qf 40L/min。研究在TBM下,膜垢的形成原因,对微分方程--＝k(J－Jlim)J2－n进行拟合,拟合R2为无机膜0.8812和0.8478;有机膜为0.9048,并分析膜垢的形成的模式：有机膜的膜垢主要是层垢(n＝0),无机膜的膜垢形成主要是层垢和部分并在膜垢的综合情况(n＝0,n＝1)。并研究TBM模式下,总糖、总果胶、总蛋白、抗氧化活性等影响果汁品质的物质的动态过程,结果表明：在P＜0.05,无机膜在品质的保持比如总糖、抗氧化活性、总酚的截留滤等方面强于有机膜,其余的品质无显著差异。     

甘蔗混合汁粒径分布及陶瓷微滤膜过滤阻力研究

建立了甘蔗混合汁中颗粒粒径分布测定和分析方法;研究了0．1μm、0．2μm和0．45μm陶瓷微滤膜分析甘蔗混合汁时的阻力分布,探讨了不同膜元件主要阻力形式,确定了阻力分析方法。结果表明：致密性膜的制造精度越高,过滤料液时总阻力相对较小,孔隙率高的膜元件堵塞阻力随膜孔径减小而降低,利于膜通量的恢复和延长使用时间。     

Effect of membrane property and operating conditions on phytochemical properties and permeate flux during clarification of pineapple juice

The effects of membrane property on the permeate flux, membrane fouling and quality of clarified pineapple juice were studied. Both microfiltration (membrane pore size of 0.1 and 0.2 μm) and ultrafiltration (membrane molecular weight cut-off (MWCO) of 30 and 100 kDa) membranes were employed. Membrane filtration did not have significant effects on the pH, reducing sugar and acidity of clarified juice whereas the suspended solids and microorganism were completely removed. The 0.2 μm membrane gave the highest permeate flux, total vitamin C content, total phenolic content and antioxidant capacity as well as the highest value of irreversible fouling. Based on these results, the membrane with pore size of 0.2 μm was considered to be the most suitable membrane for the clarification of pineapple juice. The optimum operating conditions for the clarification pineapple juice by membrane filtration was a cross-flow velocity of 3.4 ms⁻¹ and transmembrane pressure (TMP) of 0.7 bar. An average flux of about 37 lm⁻² h⁻¹ was obtained during the microfiltration of pineapple juice under the optimum conditions using batch concentration mode.     

Modeling flux behavior for membrane filtration of apple juice

The flux behavior of ceramic membranes with different pore sizes (0.2, 0.1 and 0.02 μm) was examined during dead-end membrane filtration of depectinized control (CTJ) and ascorbic acid treated (AAJ) apple juices. A new model based on an expanded exponential relationship was developed. The model represented the flux with precision over the entire filtration process for both juice types and all membrane pore sizes. Two parameters, A and B, provided a measure of the rate of flux decline. The same approach was used to model the permeate flux of CTJ for various 0.2 μm pore size polymeric membrane materials operated in a dead-end mode, and for tubular ultrafiltration membranes of different pore sizes (9, 20 and 100 kDa) operated in crossflow mode.     

Chicory juice clarification by membrane filtration using rotating disk module

Clarification is the first step of inulin production from chicory juice, and membrane filtration as an alternative can greatly simplify this process, increase juice yield, improve product quality, and reduce the cost and waste volume. In this study, a rotating disk module (RDM) was used to investigate the clarification of chicory juice by four micro- and ultrafiltration membranes. Compared with dead end filtration, the RDM had a much higher permeate flux and product quality. High rotating speeds produced high permeate fluxes and reduced flux decline, because of the strong back transport of foulant from fouling layer to feed solution. At high rotating speeds of 1500–2000 rpm, the permeate flux increased with membrane pore size and transmembrane pressure (TMP), while at low rotating speeds (<1000 rpm), permeate flux was independent of membrane type and TMP due to a thick deposited fouling layer as a dominant filtration resistance, while carbohydrate transmission decreased at higher TMP because of denser cake layer as an additional selective membrane. The highest carbohydrate transmission (∼98%) and desirable permeate turbidity (2.4 NTU) was obtained at a TMP of 75 kPa and a rotating speed of 2000 rpm for FSM0.45PP membrane. With the RDM, the Volume Reduction Ratio (VRR) could reach 10 with a high permeate flux (106 L m⁻² h⁻¹) in the concentration test, and permeate was still rich in carbohydrate and well clarified. Chemical cleaning with 0.5% P3-ultrasil 10 detergent solution was able to recover 90% water flux of fouled membrane.     

Clarification of Apple Juice Using Polymeric Ultrafiltration Membranes: a Comparative Evaluation of Membrane Fouling and Juice Quality

The aim of this study was to evaluate the performance of three different commercial polymeric ultrafiltration (UF) membranes during clarification of raw apple juice, comparatively. The influence of membrane pore size, roughness, and hydrophobicity on flux profile and fouling was investigated. The initial flux was simultaneously decreased at the beginning of the process, and quite steady flux was obtained in the membranes with rougher surface and more hydrophobic nature. As the pore size and hydrophobicity increased, the reversible fouling became the major resistance, while cake formation was more prominent for the membranes with narrower pore size. The overall quality results revealed that the main quality characteristics of the raw juice can be better retained by using the membranes that have higher resistance to fouling.     

Clarification and sterilization of raw depectinized apple juice by ceramic ultrafiltration membranes

Raw depectinized apple juice was clarified and sterilized in a cross‐flow pilot scale ultrafiltration system using ceramic tubular membranes (MEMBRALOX^®, Pall) with mean pore size of 100 nm. The permeate flux significantly decreased with time until a steady‐state was established. An increase in filtration pressure increased the permeate flux while there is an optimum pressure (about 0.85 bar) above which the increase of pressure does not increase the flux significantly. The higher the cross‐flow velocity was, the higher was the transmembrane flux. When the operating temperature increased, the permeation rate increased subsequently. Analytical measurement showed that suspended solids and turbidity could almost be removed by the ceramic ultrafiltration membrane, but pH, acidity, sugar and soluble solid content of the juices showed no significant change. The bacteria challenge tests with Micrococcus flavus showed that the logarithm value of the bacteria reduction rate came up to above 9 in the cross‐flow tubular ceramic system. When the permeate was collected in sterile bottles in a laminar flow shell and kept at 4 °C, 8 °C, 25 °C and 35 °C, for 28 days, the apple juice experienced minimal changes in physicochemical properties at lower temperatures of 4 °C, or 8 °C. Copyright © 2005 Society of Chemical Industry     

Clarification of apple juice by electroflotation

Apple Juice industry is in search of a simplified technology which enables a quick clarification and stabilisation of apple juice. This study aimed to evaluate the potential of electroflotation as an alternative for the clarification of apple juice. Clarification of apple juice by electroflotation was first done at various current densities (10, 20 and 40 mA/cm²) with and without addition of gelatin (200 mg/l). Afterwards, the electroflotation treatments were done at a current density of 20 mA/cm² with various concentrations of added gelatin (0, 50, 100 and 200 mg/l). It was shown that electroflotation treatments alone was efficient to reduce the tannin and protein contents of apple juice. However, the decrease in the protein content was in large part due to the use of pectinases prior to the electroflotation treatments. The use of gelatin in combination with the electroflotation aided in the clarification process. The highest gelatin concentration used in this study (200 mg/l) resulted in a better reduction of tannin and protein levels, while a current density of 20 mA/cm² was found to be optimal. Turbidity observed in the juices clarified with electroflotation treatments was in average lower than 10 NTU but higher than 2 NTU which is generally required to produce a stable clarified juice. Brix degree and pH of the apple juice was not affected by the electroflotation treatments while the color was improved.

Industrial relevance

The production of clarified and stable apple juice is a subject of interest for the beverages industries. The clarification step which remained long and discontinuous implied the addition of a large quantity of pectolytic enzyme and of clarifying agents (such as gelatin) to the freshly pressed juice to induce the precipitation of proteins and other suspended matter in 15–20 h. Fining treatments were followed by a separation step usually consisting of decantation and classical filtration on filter-press, or flotation by dispersed gas. The development of membrane separation processes to replace the traditional approach has enabled the automation of the whole production resulting in lower labor requirement and a considerably shorter process time than the traditional process.However, the performance of membrane separation processes is influenced by the declining permeate flux with time, which is due to membrane fouling. In some instances, permeate flux decline makes membrane separation processes unattractive for the clarification of apple juice. To our knowledge, we are the first research group to use electroflotation (EF) for clarification of apple juice. It was shown that EF treatments alone were efficient to reduce the tannin and protein contents of apple juice. In addition, the use of gelatin in combination with the EF aided in the clarification process. Turbidity observed in the juices clarified with EF treatments for 30 min was in average lower than 10 NTU. Brix degree and pH of the apple juice were not affected by the EF treatments while the color was improved.When compared to the values reported in the literature for flotation by dispersed gas, it seems that EF shows better efficiency than flotation in decreasing the juice turbidity (99% decrease for EF as compared to 90% decrease for flotation). In addition, for experiments carried out by conventional flotation larger amount of fining agent are used (70–150 mg of gelatin/l, 400–800 mg/l of silica sol and 200–500 mg/l of bentonite). For these reasons, the new process we propose is advantageous when compared to the traditional flotation approach and it should have a measurable impact on the advancements in the production of clarified apple juice. If used as a pre-treatment to ultrafiltration clarification, it is expected that it would reduce membrane fouling resulting in higher productivity.     

Apple Juice Clarification using Mineral Membranes: Fouling Control by Backwashing and Pulsating Flow

New mineral membranes of ceramic (Ceraflo) and carbon (Carbone Lorraine), were used for apple juice clarification using cross flow microfiltration. Effect on performance of the parameters transmembrane pressure, inlet flow velocity, membrane nature, and temperature were studied. Optimum permeate flux was at a transmembrane pressure of about 3.5 bar for both membranes. Formation of a concentration layer of rejected particles was reduced by using techniques backwashing and pulsating inlet flow. These techniques provided a major flux restoration and steady state permeate flux increased by 30–50% with backwash and up to 100% with pulsating inlet flow.