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。     

无机陶瓷膜浓缩APMP制浆废液的研究

采用孔径为0.2μm、50 nm和20 nm的无机陶瓷膜过滤APMP制浆废液,通过对膜孔径、跨膜压差(TMP)、体积浓缩因子(VCF)3个因素进行分析,得到最佳工艺条件:陶瓷膜孔径20 nm,跨膜压差0.2 MPa,操作温度80℃,体积浓缩因子7.6,在此条件下废液通量为891 L·(h·m2·MPa)-1,浓缩液总固形物(TS)浓度从22.57 g·L-1升高到58.38 g·L-1。     

组合式中空纤维膜澄清杨梅果酒的研究

杨梅果酒是不稳定性胶体溶液,为提高其澄清度和稳定性,采用超滤膜过滤的方法,进行了单一中空纤维膜工艺和组合式中空纤维膜工艺澄清杨梅果酒的研究。以超滤压力、时间、温度和料液流速为影响因素,探讨超滤工艺条件及膜处理方式对杨梅果酒的澄清效果和品质的影响。结果表明:在温度为28℃,压力为0.08MPa,料液流速为6L/h下,用分子截留量为80000u与50000u的组合式中空纤维膜处理后得到的杨梅果酒色度值A520为0.301,澄清度T680为96%,膜通量为25L/(m2.h),蛋白质与单宁含量明显减少,且总酸、总糖、酒精度等含量几乎无变化。     

组合式中空纤维膜澄清杨梅果酒的研究

杨梅果酒是不稳定性胶体溶液,为提高其澄清度和稳定性,采用超滤膜过滤的方法,进行了单一中空纤维膜工艺和组合式中空纤维膜工艺澄清杨梅果酒的研究。以超滤压力、时间、温度和料液流速为影响因素,探讨超滤工艺条件及膜处理方式对杨梅果酒的澄清效果和品质的影响。结果表明:在温度为28℃,压力为0.08MPa,料液流速为6L/h下,用分子截留量为80000u与50000u的组合式中空纤维膜处理后得到的杨梅果酒色度值A520为0.301,澄清度T680为96%,膜通量为25L/(m2.h),蛋白质与单宁含量明显减少,且总酸、总糖、酒精度等含量几乎无变化。      

混合酶在澄清荔枝汁中的应用研究

采用正交设计研究了果胶酶、纤维素酶、木瓜蛋白酶和α 淀粉酶联合使用对荔枝果汁澄清度、稳定性与营养成分的影响。结果表明 ,混合酶用于澄清荔枝汁的最优工艺条件是纤维素酶量 6 0 0U 10 0g ,果胶酶量 10 0 0U 10 0g ,α 淀粉酶量 2 5 0U 10 0g,木瓜蛋白酶量 10 0 0 0U 10 0g ,酶解温度 6 0℃ ,酶解时间 4h ,pH4 0 ,且pH为主要影响因素。与原汁相比 ,经混合酶处理后的荔枝澄清汁的稳定性得到提高 ,且可溶性固形物、总糖、还原糖、总酸和氨基酸含量也明显得到提高      

复合型澄清剂在磷浮法清净糖浆中的试验

介绍了一种新型无机/有机高分子阳离子与超细粉体结合的复合型糖用澄清剂在甘蔗(甜菜)糖厂糖浆磷浮法清净工艺中的生产性试验.结果表明:复合型糖用澄清剂在不同条件下的糖浆气浮清净工艺中具有高效絮凝、固液分离迅速及较强的稳定性,是粗糖浆清净的理想澄清助剂.     

不锈钢膜超滤澄清甲壳素碱煮废水的研究

不锈钢膜澄清甲壳素碱煮废水,为掌握膜通量衰减规律以及膜对料液中非碱固形物、悬浮固形物的截留规律,用5批次不同浓度的蟹壳碱煮液,全循环模式下进行变跨膜压差(TMP)实验,发现TMP小于3.1 bar时为压差控制区,大于3.1 bar时为浓差极化阻力控制区.在压差控制区内,膜通量随TMP增大而增大.TMP控制在3.1 bar,料液温度控制在70℃,平均膜通量随料液初始浓度减小而增大.分别为108.15、136.65、171.48、187.09、228.57 L·m-2·h-1,非碱固形物的截留率随时间的增加而增大.滤液的悬浮固形物含量均在0.01%以下,证明不锈钢超滤膜技术可以高效澄清甲壳碱煮液,截留全部悬浮固形物.     

膜分离技术及功能高分子膜(续)

<正> 五、制膜液的配制及膜的形成制膜液主要是由成膜有机高分子聚合物(用无机材料制膜现今尚处于试验阶段)、溶剂及添加剂等组成的。膜的形成主要是制膜的工艺条件。1.有机高分子材料有机高分子材料是构成膜架的组分。适用于制作分离膜的高分子材料在成膜     

发酵型青梅酒的微滤:膜污染分析与品质评价

采用2种不同孔径(0.2和0.5μm)的陶瓷膜对发酵型青梅酒进行微滤澄清,探究了青梅酒微滤过程的膜污染行为以及微滤对青梅酒理化性质、有机酸含量和挥发性组分的影响。Hermia膜孔堵塞模型拟合结果表明,滤饼过滤是青梅酒微滤过程的主导膜污染机制,Resistance-in-series模型结果显示,该过程主要过滤阻力为可逆阻力。微滤可以极大地提高酒体透明度,并达到理想的除菌效果。HPLC分析结果显示,微滤对酒体中的有机酸含量影响很小。顶空固相微萃取-气相色谱质谱(headspace solid phase micro-extraction gas chromatography-mass spectrometry,HS-SPME-GC-MS)分析结果则表明,陶瓷膜微滤对青梅酒挥发性组分的影响不可忽略,尤其是酯类物质的含量显著下降。综上所述,0.5μm的陶瓷膜比0.2μm更适合于青梅酒的澄清。     

基于膜技术的水飞蓟油脱胶工艺优化及脂肪酸组成的变化

使用膜分离技术对水飞蓟毛油进行精制脱胶,并进行工艺优化.以通量和脱胶率为主要指标,同时参考碘值、过氧化值、酸价等指标,对孔径分别为300、800 nm和1μm的无机氧化铝陶瓷膜以及膜截留分子量均为10 kDa的聚酰胺(PAN)膜、醋酸纤维素(CA)膜、聚醚砜(PES)膜的三种有机膜进行筛选,筛选出膜污染小、脱胶率高、通...     

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.     

Clarification of passion fruit juice by microfiltration: Analyses of operating parameters,study of membrane fouling and juice quality

In this study, the performance of two membranes were compared – tubular ceramic and hollow fiber poly(imide) – under transmembrane pressure of 0.5 and 1 bar, for the clarification of passion fruit pulp pre-treated by centrifugation and enzymatic treatment at the concentrations of 150 and 300 ppm. Nutritional and sensorial qualities of the clarified juice obtained were evaluated. Thus, it was possible to observe that the most adequate condition for the clarification of passion fruit pulp was with enzymatic treatment at 150 ppm and its posterior microfiltration at the ceramic tubular membrane of 0.3 μm with transmembrane pressure of 0.5 bar. The fouling mechanism was identified by estimation of model parameters according to a nonlinear regression by Bayesian inference. Analysis of the fouling mechanism results revealed that hollow fiber membrane is controlled by a cake filtration mechanism, and internal pore blocking fouling mechanism controls ceramic tubular membrane.     

基于红糖生产的蔗汁陶瓷膜过滤工艺技术

采用孔径为8、50 nm及500 nm的陶瓷膜对蔗汁进行过滤澄清生产红糖,解决传统红糖制作利用上浮撇泡方式处理蔗汁清净效果差导致成品糖品质低的问题.对比不同孔径陶瓷膜过滤蔗汁渗透通量大小、清净效果及能耗高低,结合红糖生产工艺需求,得出孔径为50 nm的陶瓷膜最适用于蔗汁过滤澄清生产红糖.在适合的操作条件下,考察孔径为5...     

不同预处理方式对柠檬果汁超滤澄清效果和膜污染情况的影响

利用超声辅助果胶酶法和超滤技术相结合对柠檬果汁进行澄清。以柠檬汁的透光率、果胶含量为指标,讨论不同预处理方式对柠檬果汁超滤澄清效果和膜污染情况的影响。结果表明,采用切割分子量为50 kDa的聚丙烯腈(PAN)超滤膜澄清果汁,不同预处理方式对超滤膜的稳定通量大小的影响规律是酶+超声处理>酶处理>未经酶+超声处理,其稳定通量分别为30、33.5和13 L·m^-2·h^-1左右。较优的操作压力可确定为0.1 MPa,此时柠檬汁的果胶含量为0.5%,透光率约99.6%,处理效果较好。超声辅助果胶酶法澄清果汁,有利于提高果汁的透光率,并且在后续膜处理过程中,对于提高超滤膜的通量和缓解膜污染都有显著的效果。     

Rotating Disk-Assisted Cross-Flow Ultrafiltration of Sugar Beet Juice

Rotating disk module (RDM)-assisted cross-flow ultrafiltration of sugar beet juice, obtained by cold pulsed electric field-assisted pressing, was studied in full recycling and concentration modes. Results of trans-membrane pressure (TMP) stepping tests with 10- and 50-kDa membranes showed that filtration flux increased with rotation speed and TMP until 1000 rpm and 4 bar. A slight variation of filtration purity was observed for a rotation speed range of 0–2500 rpm. A TMP increase resulted in purity reduction due to the formation of thicker fouling layer. A full recycling test study with a 10-kDa membrane confirmed the influence of TMP and rotation speed on filtration flux. A rotation speed of 1000 rpm and a TMP of 4 bar were selected for sugar beet juice purification, by concentrating juice from 13 to 1 L. The results of concentration mode tests revealed that, with a 10-kDa membrane, the filtrate purity could reach 95.6 ± 0.5 %, which was comparable to the purity of sugar beet juice purified by conventional liming-carbonation method. The flux decline in cross-flow filtration was still important, justifying more effective anti-fouling technologies investigation.     

陶瓷膜在晒制酱油生产中的应用

考察了不同工艺段酱油陶瓷膜过滤的分离效果,并以酱油沉降液为料液,优化陶瓷膜过滤条件。结果表明,陶瓷膜应用在酱油沉降工段后较佳,表现在通量衰减慢、膜污染速度慢等。最佳陶瓷膜过滤操作参数为：选用孔径B陶瓷膜,温度40～50 ℃,跨膜压差280 kPa,膜面流速5.5 m/s,反冲工作压力500～600 kPa,反冲间隔时间4 min,反冲时间3 s,反冲排气5 s,浓缩10倍,平均通量85.7 kg/（h·m2）。陶瓷膜渗透液离心无沉淀,菌落总数低于10 CFU/mL,总酸、氨基酸态氮、总氮、盐分及无机盐固形物透过率均达到98%以上。陶瓷膜技术应用在晒制酱油中值得推广。     

Identification of Fouling Mechanism During Ultrafiltration of Stevia Extract

Stevioside is one of the naturally occurring sweetener, which can be widely applied in food, drinks, medicine, and daily chemicals. Membrane separation has potential application in clarification of stevioside from pretreated stevia extract by ultrafiltration. In the present study, namely 5-, 10-, 30-, and 100-kDa molecular weight cutoff membranes have been used. Quantification of membrane fouling during ultrafiltration is essential for improving the efficiency of such filtration systems. A systematic analysis was carried out to identify the prevailing mechanism of membrane fouling using a batch unstirred filtration cell. It was observed that the flux decline phenomenon was governed by cake filtration in almost all the membranes. For 100 kDa membrane, both internal pore blocking and cake filtration are equally important. Resistance in series analysis shows that the cake resistance is several orders of magnitude higher than the membrane resistance. The cake resistance is almost independent of transmembrane pressure drop, which indicates the incompressible nature of the cake. A response surface analysis was carried out to quantify the development of cake resistance with time during ultrafiltration of various membranes. Quality parameters show that the 30-kDa membrane is better suited for clarification purposes. Identification of the fouling mechanism would aid in the process of design and scaling up of such clarification setup in future.     

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.     

灭菌和贮藏温度对荔枝汁中多酚化合物组成、含量及其抗氧化活性的影响

以俊红荔枝汁为研究对象,探究不同的灭菌方式（70 ℃和121 ℃）和不同的贮藏温度（4 ℃和45 ℃）对荔枝汁中酚类物质释放的影响。主要测定其酚类物质含量、抗氧化活性和酚类物质组成的变化。结果表明,121 ℃高温灭菌荔枝汁中的酚类物质含量和抗氧化活性显著高于荔枝原汁和70 ℃巴氏杀菌荔枝汁（P<0.05）。贮藏时间为0 h时,高温灭菌荔枝汁的氧化自由基吸收能力（Oxygen Radical Absorbance Capacity,ORAC）与荔枝原汁和巴氏杀菌荔枝汁相比分别增加了40.24%和39.00%。且在高温灭菌荔枝汁中没食子酸含量显著增加 （P<0.05）,没食子儿茶素大量生成,其中没食子儿茶素的含量约占121 ℃热处理荔枝汁中酚类化合物的91.74%。4 ℃和45 ℃贮藏条件对于荔枝汁中酚类化合物含量的变化有显著影响,其中荔枝原汁和巴氏杀菌荔枝汁在45 ℃贮藏条件下,酚类物质含量显著增加（P<0.05）,而高温灭菌荔枝汁中酚类物质含量则显著降低（P<0.05）。综上,热处理和高温贮藏对荔枝汁中酚类化合物含量的变化具有显著影响,热处理能够促进荔枝汁中酚类物质的释放进而提高其抗氧化活性。