几种国产超滤膜在苹果汁澄清中应用的比较

选用国光苹果为原料研究了超滤技术对苹果汁澄清作用的影响，筛选出了适合苹果汁超滤澄清的国产超滤膜。对国产的聚砜（ＰＳ）、磺化聚砜（ＳＰＳ）、聚砜—磺化聚砜共混膜（ＰＳ－ＳＰＳ）及聚丙烯腈（ＰＡＮ）四种膜进行筛选，通过比较压密曲线、澄清效果、衰减曲线、可溶性固形物、ｐＨ值及其它理化、感官指标，认为ＰＳ膜及ＰＳ－ＳＰＳ膜适于在苹果汁澄清中应用。     

冷榨及热榨芹菜汁超滤效果的比较及膜材料的筛选

采用国产超滤膜聚砜(PS)、磺化聚砜(CMPS)、聚丙烯腈(PAN)对芹菜冷榨及热榨汁的超滤效果进行了比较。结果表明不论超滤前还是超滤后,冷榨汁可溶性固形物、pH、透光率均比热榨汁高。热榨汁对超滤膜的污染比冷榨汁重,不论超滤芹菜冷榨汁还是热榨汁,PAN 膜抗污染能力均较CMPS、PS膜强。     

改性后的超滤膜对苹果汁中芳香成分的影响

采用中空纤维PAN膜、羧基化改性的PAN板式膜、PS膜和PS-SPS膜四种国产膜材料对苹果汁进行超滤澄清处理,选用中空纤维PAN膜和羧基化改性的PAN板式膜研究了超滤过程对芳香成分的影响.结果表明羧基化改性的PAN板式膜对芳香成分有较好的保留作用.通过大量实验证明,同时蒸馏萃取通过Likens--Nickerson装置,可达到用少量的溶剂提取大量食品中芳香物的目的.该法具有缩短实验时间、操作简便、节约试剂等特点.     

超滤技术在芹菜汁澄清工艺中的应用研究

选用芹菜(犹他改良5270品种)为原料,研究了国产超滤膜聚砜(PS)、磺化聚砜(CMPS)、聚丙烯腈(PAN)对芹菜澄清汁的质量影响,获得了超滤芹菜汁的工艺参数。结果表明,国产PAN-1万平板超滤膜对芹菜汁的澄清效果明显,在0.15MPa压力下,透光率由18.7%.上升至98.8%,除果胶和蛋白质被截留外,超滤前后芹菜汁中可溶性固形物、总糖、还原糖、pH、矿质元素的含量变化不大,表明超滤可较大程度地保存芹菜汁中的营养物质。     

超滤膜澄清酱油的研究

酱油是人们日常生活中所必须的一种调味品,为提高酱油品质,减少杂质和细菌,选用聚砜、磺化聚砜、聚丙烯腈、聚醚砜等多种材料和不同切割分子量（ＭＷＣＯ）的平板膜对酱油进行了超滤实验,并对被污染的膜进行清洗实验,从而确定了适用于超滤澄清酱油的膜材料和清洗剂浓度。     

超滤澄清海螺报春花提取液的研究

研究了聚砜中空纤维膜超滤海螺报春花提取液过程中不同截留分子量的膜组件及操作压力和温度对膜通量的影响 ,比较了几种清洗剂清洗后膜通量的恢复率。结果表明 ,超滤可以有效地澄清报春花提取液 ,为超滤技术应用于报春花的开发提供了依据。     

超滤法澄清西番莲果汁的研究

以寻求提高西番莲原汁超滤时的渗透通量为目的，用国产芳香聚酰胺膜平板超滤器进行试验，对超滤操作条件，果汁预处理，膜的清洗进行研究。结果表明，西番莲原汁超滤时渗透通量最高的操作压力为0．15MPa，最佳进料速度为22mL/s，操作温度为室温；原汁经海藻酸钠—碳酸钠澄清剂预处理后可以明显增大渗透通量；超滤处理后。原汁的西番莲固有滋味和品质得到较好保留。采用超滤澄清法生产高质量的西番莲原汁是可行的。     

电子鼻检测改性聚砜膜用于啤酒澄清处理的研究

为研究膜处理技术对啤酒风味的影响,使用自制的共混改性聚砜膜(孔径100 nm)处理精滤前的啤酒,选用电子鼻PEN3系统对啤酒原液及膜澄清处理过的2种啤酒的芳香成分进行分析。通过电子鼻系统动态采集啤酒芳香成分,得到电子鼻的响应值,使用PCA、LDA模式识别方法进行数据分析。分析结果表明电子鼻能够快速、无损地检测到不同处理工艺对啤酒风味的影响,为检测共混改性聚砜膜对啤酒的澄清效果提供技术支持。     

超滤技术对苹果汁中芳香成份的影响

研究了不同截留分子量的国产聚砜膜对国光苹果超滤汁中几种芳香成份的影响。结果表明:国产聚砜膜对国光苹果汁中的酯类和醛类物质影响较大,能较好地保留醇类物质。不同截留分子量的聚砜膜中,尤以10000dalton的膜对芳香成份的影响最小,其对丁酸乙酯和醇类的保留率分别为61.4％和97.2％～78.6％。     

陶瓷膜在苹果汁澄清中的应用研究

采用国内研制的陶瓷膜进行苹果汁的澄清实验研究.实验结果表明氧化锆陶瓷膜可有效地澄清苹果汁,澄清果汁的各项指标达到出口果汁指标;并与国外陶瓷膜设备作同期运行对比,其澄清效果、通量的稳定性等方面均达到或超过国外陶瓷膜的处理结果.同时实验还对湍流促进器强化无机膜微滤过程以及膜清洗方法进行了考察,确定了无机陶瓷膜膜过滤苹果汁合适的操作参数.     

Clarification of Apple Juice by Hollow Fiber Ultrafiltration: Fluxes and Retention of Odor-Active Volatiles

Fresh apple juice was clarified in a pilot scale ultrafiltration (UF) unit, with membranes made of polysulfone and polyamide and plate and frame and vacuum drum filters. Flux of apple juice (L/m² hr) vs UF transmembrane pressure data showed an optimum at a pressure of about 140 kPa. Retention of odor-active volatiles was highest in plate and frame filtered apple juice and lowest in vacuum drum filtered juice; the retention of odor-active volatiles in UF juice was intermediate to the two traditional filtration methods. Retention of odor-active volatiles in the permeate of a polyamide membrane was higher than that of a polysulfone membrane.     

Effect of membrane pore size on quality of ultrafiltered apple juice

Fresh apple juice was processed using an ultrafiltration (UF) unit, with polysulphone membranes of 10 000 and 50 000 daltons pore size. Trans-membrane pressures of 103, 120.5, 138 and 155 kPa were studied. Recovery percentages of 0, 25, 50 and 75 were tested for the smaller pore membrane, as well as 0, 10, 20, 30, 40, 50 and 60 for the larger pore membrane. The responses to these factors were evaluated for the quality attributes pH, acid content, soluble solids and colour. In general terms, pH, acid content, and soluble solids did not change but presented less variability for the smaller pore membrane treatment. Relative colour changes were observed for both membranes, with an evident browning trend, which was more detectable for the larger pore membrane treatment.     

膜技术在苹果汁加工中的应用

应用平板式超滤技术对苹果浊汁进行了过滤澄清和除菌。研究了巴式杀菌酶解或未酶解的苹果浊汁、未巴式杀菌未酶解的苹果浊汁、温度对膜通量的影响,超滤组件形式、操作参数对3种不同预处理料液的滤液质量的影响及反渗透系统的浓缩效果。结果表明:平板式超滤膜通量能满足工业需求且大于管式超滤膜,操作温度宜为50℃,当加水倍数0.09倍时,可使浓缩倍数达到20倍。苹果汁超滤液的透光率在97%以上、色值在50%以上、浊度指标小于0.3,pH值、总酸、糖度、氨基态氮等却未发生明显的变化。苹果汁超滤液质量指标和耐热细菌检查结果比较表明,平板式超滤可代替对苹果汁巴式杀菌及酶解。反渗透系统对苹果汁超滤液进行浓缩,浓缩倍数为2～2.3倍,糖截留率为100%。     

Production of Microbiologically Stable Apple Juice by Metallic Membrane Ultrafiltration

The potential for production of microbiologically stable apple juice by metallic membrane ultrafiltration was assessed. Thermal sterilization treatments caused no detectable changes in membrane performance. Sterile membranes were challenged with approximately 3 × 10⁶ colony forming units per gram of each of three organisms, Pseudomonas diminuta, Bacillus coagulans, and Saccharomyces cerevisiae, suspended in apple puree or peptone. Reductions achieved by ultrafiltration of peptone at operating pressure were 5.1, 7.6, and >9.0 logs for the three organisms, respectively. Reductions of organisms in apple puree were at least 1.5 logs greater. Metallic membranes eliminated yeasts and molds from juice. Apple juice produced from uninoculated apple puree was stable at 20–25°C for 1 yr.     

Evaluation of hybrid pressure-driven and osmotically-driven membrane process for non-thermal production of apple juice concentrate

This study investigates the potential of hybrid membrane processes including microfiltration (MF), ultrafiltration (UF) and forward osmosis (FO) for non-thermal concentration of apple juice. The process performance and characteristics (physicochemical properties, nutritional and aroma components and microbiological quality) of apple juice were studied. The clarity of apple juice was significantly promoted as pore size of membrane reduced. MF and UF can also ensure microbiological safety in pre-treated apple juice. According to its efficiency of filtration as well as performance of simultaneous clarification and cold-sterilization, 0.22 μm MF membrane was identified as the optimal membrane for the pre-treatment. The pre-treated apple juice can be concentrated up to 65°Brix by subsequent single stage FO. FO retained nutritional and volatile compounds of apple juice while significant reductions were found in the juice concentrated by vacuum evaporation. Hybrid MF-FO can be a promising non-thermal technology to produce apple juice concentrate with high quality.     

不同国产超滤膜对苹果浓缩汁产生后混浊影响的比较

ＰＳ－ＳＰＳ、ＰＳ、ＳＰＳ、ＰＡＮ四种国产超滤膜对苹果浓缩汁产生后混浊的影响不同。利用上述四种膜澄清制得的澄清汁经减压蒸发浓缩制成苹果浓缩汁常温放置三个月后测Ｔ值及后混浊沉淀湿重,以用ＰＳ澄清制成的浓缩汁发生后混浊最为严重,其余三种差异不显著。ＰＳ－ＳＰＳ共混膜具有较高的工业化应用价值。     

Ultrafiltration and reverse osmosis for clarification and concentration of fruit juices at pilot plant scale

The process of ultrafiltration of raw juices (peach, pear, apple and mandarin) through tubular polysulphone membranes (8 kDa) and finally concentrated by reverse osmosis membranes of tubular composite polyamide film (99 g/100 g NaCl rejection) with filtration area of 0.9 m² was studied. Furthermore, in order to obtain a higher permeate flow, the fluids were previously treated with commercial pectinolytic enzyme.The following parameters were analyzed: permeate flow, soluble solids, viscosity, density, pH, acidity, formol index, starch, pulp content, color and presence of pectin. The use of a pectinolytic enzyme provides increased permeate flux of approximately 40%, retaining the juice properties. The highest total soluble solids content was clarified peach juice from 12.2 °Brix concentrated up to 30.5 and 21.52 °Brix by using RO with transmembranes pressures of 4 and 2 MPa respectively.The results show a cross-flow velocity (1.8 m/s) which corresponds with Reynolds number that is on the lower border of a laminar flow and above of transition rate (2090 < Re < 2900). Also the (VCF) for mandarin (1.49), pear (1.53), apple (1.56) and peach (1.58) was obtained for RO process. The membranes used were characterized morphologically using scanning electron microscopy.