E 65/E 75高性能精梳机

立达的新一代精梳机E 65/E 75从工艺上和技术上把精梳技术推向了高性能的新纪元.现在450钳次/min的钳速已经在车间实际生产条件下实现.详细介绍了新一代精梳机E 65/E 75的工艺特性及其精梳条的特点和对后道工序的积极作用.     

E 65/E 75:高性能精梳机的新境界

Rieter公司的新一代精梳机E65／E75从工艺上和技术上把精梳技术推向了高性能的新纪元。现在450钳次／min的钳速已经在车间实际生产条件下实现。下面详细介绍新一代精梳机E65／E75的工艺特性及其精梳条的特点和对后道工序的积极作用。     

国内外精梳技术现状和发展展望

分析了我国发展和扩大精梳生产、加快产品结构调整的必要性,详细介绍了引进较多的瑞士立达公司E7/4、E7/5、E7/6、E62以及E72、E65、E75等机型的技术特征,还对国内上海纺机总厂等制造的精梳机进行了分析,提出了我国发展精梳生产的几点意见,认为精梳技术应向机电一体化、自动化方向发展,采用多电动机同步传动技术,提高配件的材质、加工精度和装配精度,在稳定、可靠的基础上提高速度,才能有效地提高生产效率.     

立达高性能精梳机

描述了瑞士立达机械公司生产的新一代E 65/E 75(机器成卷)型精梳机的特性和应用.E 65/E 75从技术和工艺上推进了高性能棉精梳机的发展.目前,在纺优质纱线的精纺工艺中,它的罗拉钳口速度已可达到450 钳/min.     

FA355型条并卷机的结构特点和生产使用情况

一、几种精梳准备工艺路线的特点目前国内外采用精梳小卷的准备工艺大体上有以下三种: 1.梳棉条→预并→条卷→精梳国内精梳准备工序多数采用。如A272F预并条机→A191B型或FA331型条卷机→A201D或FA251A型精梳机。 2.梳棉条→条卷→并卷→精梳如立达公司:E2/4a型条卷机→E4/1a型     

新型的立达精梳机

新型的E65型和E75型精梳机（图1）是世界上最先在纺纱厂运转中速度达到每分钟450钳次的精梳机,且每台机器精梳条的日产量超过1500kg。     

E65型精梳机喂棉工艺研究

分析精梳机喂棉长度、小卷定量对梳理效果、精梳落棉率及分离接合质量的影响.在E65型精梳机上采用不同的给棉长度及小卷定量,进行了CJ 14.6 tex纺纱工艺参数对比试验,测试了精梳落棉率、精梳台时产量、成纱条干、成纱千米细节、成纱千米粗节、成纱千米棉结.结果表明:在新型高效精梳机上,采用较小的喂棉长度及较大的小卷定量,可提高精梳机的梳理效果、改善成纱质量.     

精梳彩色棉转杯纱的生产

探讨转杯纺纺制精梳彩色棉针织用纱的生产工艺.选用配比为75%的棕色棉和25%的本白棉混和纺制了24 tex针织用精梳转杯纱,对精梳落棉率、分梳辊速度、转杯速度等工艺参数进行了优选试验,并对精梳彩色棉转杯纱的质量进行了分析.结果表明:精梳落棉率为23%、转杯纺分梳辊速度为6 700 r/min、转杯速度为42 000 r/min时,精梳彩色棉转杯纱质量好,其质量优于普梳彩色棉转杯纱和普梳彩色棉环锭纱.认为在转杯纺纱机上开发精梳彩色棉细号纱是可行的.     

浅析E65型精梳机

剖析E65型精梳机的性能特点.概述了变速传动技术、三上三下附压力棒曲线牵伸系统等创新技术在E65型精梳机上的应用,同时也提出了E65型精梳机输出棉网边缘状态不佳、分离罗拉传动机构组成复杂等缺陷.指出:我国纺机制造企业应加强吸收国外先进技术,改进其技术缺陷,尽快研发出具有自主知识产权的新一代国产精梳机.     

天丝短纤棉纺精梳工艺研究

为了获得天丝短纤的棉纺精梳优化工艺,采用理论分析与试验研究的方法,通过天丝短纤的纤维性能测试与对比,设计相应的精梳工艺,并通过调节精梳机的落棉隔距、车速、曲柄半径等工艺参数,进行天丝短纤的精梳生产试验。结果表明:小卷定量小于65 g/m,采用前进给棉,给棉长度4.3 mm,顶梳插入深度-0.5,分离罗拉定时调节盘搭接刻度+1.5,落棉隔距10 mm,,曲柄半径55 mm,车速280钳次/min的工艺方案时,精梳机落纤率为4.78%,精梳条条干CV为4.81%,精梳条总棉结数为11个/g,保证了低落纤率的基础上,有较好的精梳质量。     

AMYLOLYSIS OF SORGHUM STARCH AS INFLUENCED BY CULTIVAR,GERMINATION TIME AND GELATINISATION TEMPERATURE

The susceptibility to amylolysis of starches derived from two improved Nigerian sorghum cultivars were evaluated at assay temperatures between 50°C and 75°C. Enhancement of gelatinisation rates at temperatures up to 65°C was not significant inspite of the apparent grain modification due to germination for four days. Greater starch gelatinisation rates (20–22%) were achieved in this study compared to previously reported values, suggesting possible roles for cultivar and malting methods. There was a statistical correlation between starch gelatinisation rates over the temperature range 65°C–75°C and the duration of grain germination (r=0.91 for KSV8 and r=0.5 for SK5912 starches). Gelatinisation rate and temperature were affected significantly by assay pH. The occurrence of two pH related maxima of starch gelatinisation for both cultivera at all temperatures examined indicates the possible presence of two sets of “binding forces” within the starch granules and features of starch retrogradation .     

基于HS-SPME-GC-MS和PCA的不同萃取头对鸡肉香精香气成分萃取效果比较

为提高鸡肉香精香气成分分析的可靠性,比较不同纤维涂层萃取头萃取鸡肉香精香气成分的效果,采用顶空固相微萃取(headspace solid-phase micro-extraction,HS-SPME)结合气相色谱质谱联用仪(gas chromatography-mass spectrometry,GC-MS)检测技术对热反应鸡肉香精中的挥发性风味物质种类和组成进行提取分析,通过灵敏性及主成分分析(principal component analysis,PCA)法比较香气成分数量及含量建立香气品质评价模型,研究不同纤维涂层萃取头(75μm CAR/PDMS、65μm DVB/PDMS、85μm PA、50/30μm DVB/CAR/PDMS)与所萃取挥发性物质间的相关性。结果表明,75μm CAR/PDMS萃取头为萃取鸡肉香精样品挥发性物质的最优萃取头,萃取得到样品中共含有146种挥发性物质,包括醇类24种(16.44%)、醛类16种(10.96%)、吡嗪类12种(8.22%)、呋喃(酮)类13种(8.91%),含硫化合物10种(6.85%)等多种香气物质,检测到2-甲基-3-呋喃硫醇、2-甲基-3-戊烷硫醇、(E,E)-2,4-癸二烯醛、(E,E)-2,4-庚二烯醛及反式-2-壬烯醛等关键肉香味化合物。     

基于SPME-GC-MS和PCA的不同萃取头对新疆烤羊肉香气成分萃取效果比较

以烤羊肉中关键挥发性物质的萃取效果为目的进行萃取头类别筛选。采用固相微萃取、气相色谱-质谱联用检测技术,对新疆石河子地区烤羊肉样品的挥发性风味物质的种类和组成进行提取和分析。以灵敏性及主成分分析（principal component analysis,PCA）法得到的载荷矩阵中投影大于0.80的关键共有物质作为筛选最优萃取头的依据,研究不同纤维涂层萃取头（75?μm?CAR/PDMS、65?μm?DVB/PDMS、85?μm?PA、100?μm?PDMS、50/30?μm?DVB/CAR/PDMS）与所萃取的挥发性物质之间的相关性。结果表明：经灵敏度检验、PCA后确认75?μm?CAR/PDMS为萃取烤羊肉样品中关键挥发性物质的最优萃取头,萃取得到样品中的关键香气成分为1-辛烯-3-醇、庚醛、正戊醛、十二醛、己醛、苯甲醛、1-十四炔、萘、4-甲基壬酸、反-2-癸烯醛、6-甲基庚醛、对异丙基苯甲醛、癸醛、壬醛、2-甲基-3-甲硫基呋喃、辛醛、联二苯。     

Piezoelectric Flow Injection Analysis Biosensor for the Detection of Salmonella Typhimurium

ABSTRACT: Piezoelectric biosensors have the potential to provide direct detection of food contaminants, such as pathogens. In this study, Protein A antibody immobilization was used for the activation of the piezoelectric biosensor to detect Salmonella typhimurium. The overall system consisted of a new design for a flow cell and flow injection analysis system. The flow cell made possible a baseline stability of ± 1 Hz out of 5 MHz for hours. The sensor had responses of 5 to 65 Hz in 30 min with R²= 0.95 for S. typhimurium concentrations of 10⁷to 10⁹ CFU/ml under continuous flow, and 3 to 75 Hz in 40 min with R²= 0.96 for S. typhimurium concentrations of 10⁶ to 10¹⁰ CFU/ ml under stop flow. Cross-reactivity tests were performed with nonpathogenic Escherichia coli, Escherichia coli O157:H7, Listeria monocytogenes , and Vibrio parahaemolyticus and showed less than 10% response.     

Mechanism of Bacillus subtilis spore inactivation induced by moderate electric fields

Bacterial endospores are the key safety targets for inactivation within low-acid foods. Herein, we investigated the inactivation of Bacillus subtilis CGMCC 1.1087 spores (10⁷ CFU/mL) in sterile distilled water using moderate electric fields (MEF, 300 V/cm) under various temperatures (<30, 55, 65 and 75 °C). MEF treatment at below 30 °C resulted in 0.6-log reduction of spores, while treatments for 60 min without electric fields showed no inactivation. Inactivation induced by MEF in the same treatment time increased to 1.8-, 2.0- and 2.5-log as temperature increased to 55, 65 and 75 °C. Spores treated with MEF at <30, 55, 65 and 75 °C or mild heat (55, 65 and 75 °C) scarcely lost heat resistance, suggesting that spores did not germinate during MEF or mild heat treatment. The viability of MEF-treated spores did not increase by addition of lysozyme (3 μg/mL) in recovery plates, preincubation for 1 h in a 1:1 mixture of 60 mM Ca²⁺ and DPA, or lysozyme treatment in hypertonic medium. Confocal laser scanning microscopy photomicrographs showed that exposure to MEF induced a marked increase in the permeability of inner membrane and cortex. These findings suggested that damage of the cortex and inner membrane, rather than spore nutrient germinant receptors or cortex lytic enzymes, are possible reasons contributing to inactivation of B. subtilis spores by MEF. This study indicates that MEF at mild temperatures (55 to 75 °C) have the potential for spore inactivation.Industrial relevanceLiterature in the past few years has shown that moderate electric fields (MEF), typically associated with ohmic heating, have nonthermal effects on bacterial spores, leading to accelerated inactivation. The current work extends the range of temperatures to those well below thermally lethal conditions, and shows that some spore inactivation occurs under MEF, even when temperatures are sublethal. Little or no germination is observed, and spore inner membranes are increasingly compromised over time. The elucidation of such nonthermal effects would be significant to the food industry as it seeks increasingly nonthermal methods for inactivation of spores.     

New Automated Microwave Heating Process for Cooking and Pasteurization of Microwaveable Foods Containing Raw Meats

ABSTRACT: A new microwave heating process was developed for cooking microwaveable foods containing raw meats. A commercially available inverter-based microwave oven was modified for pasteurization of mechanically tenderized beef, inoculated with Escherichia coli O157:H7 (approximately 5 log₁₀ CFU/g) and packaged in a 12-oz CPET tray containing 150-mL de-ionized water. The new microwave heating system was equipped with an infrared sensor and a proportional feedback mechanism to allow temperature controlled microwave heating. A 2-stage heating strategy was adopted to cook the product. In the primary heating stage, the sample surface temperature was increased to an initial temperature set-point (ITSP, 65, 70, 75, or 80 °C). In the secondary heating stage, the heating was continued with a small fraction of microwave power. The effect of ITSP, hold time (0 to 3 min), and sample elevation (0, 0.03, and 0.07 m above turntable) on inactivation of E. coli O157:H7 and background microflora was evaluated. It was observed that only a small number (approximately 1.3 logs) of E. coli O157:H7 and background microflora were inactivated in the primary heating stage. The elevation 0.07 m, which was in the proximity of the geometric center of the metal cavity, was more effective in inactivating both E. coli O157:H7 and background microflora. Substantially more bacteria were inactivated in the secondary heating stage. Complete inactivation of E. coli and background microflora was observed with heating at temperatures above 70 °C for more than 1 min. This study demonstrated a new approach for ensuring the safety of microwaveable products containing raw meats.     

Effects of high-pressure carbon dioxide on Escherichia coli in nutrient broth and milk

Bactericidal effects of high-pressure carbon dioxide against Escherichia coli were studied under 100, 75, 50 and 25 bar at 20 degrees C, 30 degrees C and 40 degrees C. E. coli suspended in nutrient broth (NB, pH = 6.75) was inactivated under 100, 75, 50, and 25 bar CO2 treatments for 50, 65, 100, and 140 min at 30 degrees C, respectively. Acidification of nutrient broth by dissolved CO2 alone might account for the bactericidal effect under pressure. E. coli was inactivated in NB with initial pH 5.50 and 4.5 at 100 bar for 80 and 95 min, respectively. Treatment at 100 bar CO2 pressure for 6 h caused a decrease of 6.42 and 7.24 log cycles in whole and skim milk, respectively.     

The Evaluation of Mechanical,Thermal, Optical and Microstructural Properties of Edible Films with Solid Lipid Nanoparticles-Xanthan Gum Stored at Different Temperatures and Relative Humidities

Solid lipid nanoparticles (SLN) were obtained using the hot homogenization method and incorporated into a xanthan gum matrix (XG) to prepare edible films. The effects of SLN content (60, 65, 70, and 75 g/L) on the mechanical, color, thermal and microstructural properties, and water vapor permeability (WVP) were studied. The SLN film-forming systems remained stable for 7 weeks. Particle size was in the range of 222–257 nm. The mechanical properties of the films improved significantly when the SLN were introduced into the polymeric network to provide greater strength and flexibility with elongation at breaking of 2–9 %, affected by temperature (4–25 °C), SLN concentration (60–75 g/L), and relative humidity (60–90 %). WVP was lower when edible films based on XG were incorporated with SLN at values of 0.50–0.70 g m-2 h-1 kPa^?1. The distribution of the SLN in the XG matrix was observed under scanning electron microscopy and showed changes in the arrangement as a function of SLN concentration. This explains the positive effect on the properties of the film of SLN-XG at 60 and 65 g/L. Total color difference (ΔE) increased with SLN content at values of 3.5–14. Thermal analysis showed that higher SLN content increased the melting temperature, while the plasticizer reduced it.