知识工程在食品包装机械设计领域中的应用研究

知识工程和计算机辅助的产品设计系统的结合是近期研究的热点。本文介绍了我国食品包装工业的发展,食品包装机械设计的特点,提出了将知识工程的概念引入到食品包装机械的设计中。介绍了UG软件关于知识工程的解决方案-UG/KF知识熔接技术,以及利用UG/KF技术的食品包装机械智能设计系统的框架组成。     

基于UG的玻璃器皿套色印花机的参数化设计

基于UG的二次开发技术UG/GRIP和Menu Script,提出了玻璃器皿套色印花机的参数化设计思想,并针对相关部件举例编写了参数化设计系统.     

烟草半胱氨酸蛋白酶抑制剂（CPI）基因家族的克隆及组织表达谱分析

运用生物信息学方法,结合RT-PCR和SMART RACE技术从烟草（Nicotiana tabacum）中克隆了4个CPI基因的全长cDNA序列,分别命名为NtCPI1、NtCPI2、NtCPI3和NtCPI4, GenBank登陆号分别为KF057988、KF057989、KF057990和KF057991。基因序列分析表明4个基因分别编码98、98、120和123个氨基酸残基的蛋白质,都具有CPI反应位点的保守基序GG、QXVXQ和A/PW,同时具有植物CPI所特有的LARFAV基序,其中NtCPI3和NtCPI4的N端还包含一段27个氨基酸残基组成的信号肽。实时荧光定量PCR试验表明,4个基因的组织表达谱很广,在根、茎、叶和芽组织中都有表达。这些结果为进一步研究半胱氨酸蛋白酶抑制剂在植物中的生理功能奠定了基础。      

UG软件及其在包装机械设计中的应用

介绍UG软件三维仿真设计技术特点,从三维造型,装配仿真,有限元分析和结构优化,三维实体向二维图纸转化等几个方面,展示了该软件系统的优越性,探析UG软件在包装机械设计中的应用。     

植物源双功能染整制剂的制备及其在羊毛织物上的应用

文章选用天然植物材料KF,通过水提取及提取工艺优化,形成植物源双功能染整制剂KF - CT;然后用此制剂对羊毛织物进行染整处理,进一步测试表征了织物的颜色特征值,染色牢度和防蛀性能.研究结果表明,KF - CT的最佳提取工艺为浴比1:10,时间90 min,温度90℃,提取2次;KF - CT染色后的羊毛织物具有较好的防蛀性能,色牢度也符合国家标准.由此可见,植物源双功能染整制剂KF - CT在羊毛织物的应用方面表现出较好的染色和防蛀特性,具有良好的开发应用价值.     

基于UG软件的压铸模具设计

UG软件功能是由美国EDS公司开发的集CAD/CAM/CAE功能于一身的软件集成系统,它实现了设计优化技术与基于产品和过程的知识工程的组合,本文以UG软件为平台应用MoldWizard模块进行压铸模具设计。     

负载型固体碱催化制备生物柴油重复性能比较

采用共沉淀、浸渍及焙烧的方法制备了Ca O/Mg-Al-O及Ca O/Zn-Al-O固体碱催化剂;采用共沉淀、焙烧及研磨的方法制备了KF/Mg-Al-O及KF/Ca-Al-O固体碱催化剂。采用醇洗、干燥及焙烧的方法对使用过的催化剂进行活化处理后用于下一次实验。以蓖麻油和甲醇的酯交换反应为活性评价反应,考察了催化剂重复使用次数对催化剂活性的影响。应用Hammett指示剂滴定法、XRD技术对新催化剂及使用后经活化处理的催化剂进行了表征,并对催化过程中碱溶解流失和析出的甘油量、总甘油量进行了测定。结果表明:Ca O/Mg-Al-O、Ca O/Zn-Al-O、KF/Mg-Al-O和KF/Ca-Al-O固体碱催化剂第一次使用催化活性很好,第二次使用催化活性较差;新催化剂的碱量均比使用过的催化剂的碱量高得多;新催化剂的晶体结构和使用过的催化剂的晶体结构差别很小;新催化剂的碱溶解流失均比较大,且生成的甘油量均较多。     

基于UG的齿轮刀具设计及切齿仿真加工研究

利用计算机仿真技术，结合计算机图形学技术，在企业普遍使用的UG CAD平台上，对常用齿轮刀具进行参数设计计算并仿真加工齿轮，对形成齿廓的过程进行动态仿真，帮助刀具设计者验证刀具的齿形参数合理与否，减少甚至避免试切，直接降低齿轮的试切、调试费用，缩短试制周期。同时，提出把C／S结构引入到UG二次开发中，实现了MFC、UG／Open和C／S结构三者相结合的应用。     

基于UG的通用凸轮曲线三次开发技术

凸轮曲线是凸轮驱动从动件的运动曲线,它影响到凸轮机构的效率、精度以及寿命,故在凸轮设计中十分重要.为快速有效地进行凸轮机构设计,总结推导了通用凸轮曲线公式,综合应用Visual C++6.0、UG/OPEN MenuScript、UG/OPEN UIStyler和UG/OPEN API等开发工具,开发了基于UG软件的通...     

KF/MMT固体碱催化剂的制备及催化酯交换反应

采用蒙脱土（MMT）为载体,通过浸渍法制备了KF/MMT固体碱催化剂,将其应用于大豆油制备生物柴油的酯交换反应中。通过XRD、FTIR、Hammett指示剂法、N2吸附-脱附、SEM等方法对KF/MMT催化剂结构进行了表征,并考察了酯交换反应条件对生物柴油产率的影响。结果表明：负载的KF与载体蒙脱土之间存在相互作用,催化剂表面存在Al—O—K活性中心;以KF/MMT为催化剂,在催化剂用量4%,醇油摩尔比12∶1,反应温度65℃,反应时间2.5 h条件下,生物柴油产率达到97.4%。     

Fabrication of gastric floating controlled release tablet based on konjac glucomannan

This paper investigated the effect of ball-milling time on the structure, floating and controlled-release properties of konjac flour (KF). After 8 h of ball milling, the particle size of KF decreased from 152 μm to 19.8 μm. The structural change of KF was characterized by repose angle, GPC-MALLS, X-ray diffraction (XRD) and scanning electron microscope. The results indicated that longer ball-milling time lead to higher repose angle, lower molecular weight and coarser surface of KF. Compared with native KF, the 4 h ball-milled KF achieved the shortest floating lag time, the longest floating duration time and the best controlled-release properties when used as excipients in floating drug release system. The water distribution in tablets with different dissolution time was observed by Magnetic resonance imagining (Wolk and Dahan). For KF-4, the hydrogelling layer could prevent moisture into the inner in order to achieve the control release.     

Factors affecting the adsorption of Lactobacillus plantarum bacteriocin bacST8KF to Enterococcus faecalis and Listeria innocua

Bacteriocin ST8KF (bacST8KF), produced by Lactobacillus plantarum ST8KF isolated from kefir, inhibits the growth of Enterococcus faecalis E88, Lactobacillus casei LHS, Lactobacillus curvatus DF38, Lactobacillus sakei DSM 20017^T, Lactobacillus salivarius 241 and Listeria innocua LMG 13568. Eighty per cent of bacST8KF adsorbed to La. casei LHS and La. sakei DSM 20017^T. However, the same level of adsorption was recorded to bacST8KF-resistant Lactobacillus paraplantarum ATCC 700211^T and Streptococcus caprinus ATCC 700066, suggesting that adherence to the cell surface occurs at random and not always at specific receptor sites. Adsorption of bacST8KF is affected by inorganic salts, acids, surfactants, alcohols, temperature and pH, as observed for E. faecalis E88 and Li. innocua LMG 13568. The target of bacST8KF is the cytoplasmic membrane, as indicated by changes in cell morphology and leakage of DNA and β-galactosidase from cells of E. faecalis E88 and Li. innocua LMG 13568 treated with bacST8KF. However, the mode of activity against E. faecalis E88 and Li. innocua LMG 13568 is bacteriostatic, as concluded from slight increases in optical density levels after a few hours in the presence of bacST8KF. Activity of bacST8KF doubled (from 12 800 AU mL⁻¹ to 25 600 AU mL⁻¹) when strain ST8KF was grown in the presence of Li. innocua LMG 13568, which may indicate some sort of quorum sensing.     

Influence of konjac flour on foaming properties of milk protein concentrate and quality characteristics of gluten‐free cookie

The effects of konjac flour (KF) for modifying the foaming properties of milk protein concentrate (MPC) and characteristics of gluten‐free rice cookies were investigated. The three variables of konjac concentration (0.1–0.4%), pH (pH 5–9) and NaCl concentration (0.2–0.6 м) were studied. Both KF and pH had considerable effects on the foaming capacity (FC) and foaming stability (FS) of MPC. The NaCl had a negligible effect. Lowered FC and FS observed at pH 9 and pH 5 were increased with the increase in KF addition. Batter characteristics (flowability and consistency), cookie quality (moisture, yield, spread ratio, specific volume, hardness and colour) and sensory acceptance were evaluated in gluten‐free cookies with 0%, 0.25% and 0.4% KF. Konjac supplementation increased batter characteristics, yield, specific volume and hardness, but decreased lightness. Panellist acceptance, especially regarding texture and overall acceptability, increased in gluten‐free cookies with 0.4% KF. A higher purchasing decision was found for cookies with added KF.     

The Use of a Custom-Built Coulometric Karl Fischer Instrument for the Determination of Water Content in Chocolate

A Karl Fischer (KF) coulometric titration method was designed and optimized for the quantitative determination of water in chocolate. A number of essential KF experimental parameters were investigated and assessed, including a study of polar extraction solvents, extraction times, interfering side reactions, and a comparison of pyridine-free KF coulometric reagents. The optimized protocol was found to be applicable to a wide variety of chocolate samples. Typical coulometric titration times for the chocolate samples were between 1 and 5 min, translating to water contents from 0.18 to 0.38 %?w/w. With this contribution, the quantification of water in chocolate using KF titration methods is now a simple, safe, and reliable process, comparable in terms of precision and accuracy to any commercially available KF coulometric apparatus.     

Engineering a hybrid pseudomonad to acquire 3,4-dioxygenase activity for polychlorinated biphenyls

We constructed a hybrid strain that acquired 3,4-dioxygenase activity for polychlorinated biphenyls (PCBs). This strain, KF707-D34, possessed a chimeric biphenyl dioxygenase gene, of which a portion of bphA1 (coding for a large subunit of biphenyl dioxygenase) of Pseudomonas pseudoalcaligenes KF707 was replaced with that of a PCB-degrader, Burkholderia cepacia LB400 by homologous recombination. KF707-D34 retained the ability to degrade 4,4'-dichlorobiphenyl via 2,3-dioxygenation in a fashion identical to that of KF707 and gained novel capability to degrade 2,5,4'-trichlorobiphenyl and 2,5,2',5'-tetrachlorobiphenyl via 3,4-dioxygenation in a fashion identical to that of LB400. Sequence analysis of bphA1 from KF707-D34 revealed that three nucleotides in the 3'-terminal region of KF707 bphA1 were changed to correspond to those in LB400 bphA1. The resulting BphA1 protein in KF707-D34 was changed at position 376 from threonine (Thr) to asparagine (Asn). The results demonstrate that a minor alteration of the amino acid sequence in BphA1 improved the PCB degradation capability in biphenyl-utilizing bacteria.     

Evaluation of low-fat sausage containing desinewed lamb and konjac gel

Ground (GR) or desinewed (DS) lamb trimmings were combined with a konjac flour (KF) gel (0%, 10% or 20%) to produce a low-fat (8%) cured sausage. Physiochemical, sensory and shelf-life analyses were performed to determine the efficacy of the fat mimetic. Desinewing reduced collagen content (2.3 mg/g tissue) and cook yield (0.6%) when compared to GR trimmings. Grinding increased aerobic plate counts (APCs) ～0.4log(10)/cm(2) more than DS, but APCs were not affected by inclusion of KF. Sausages with 20% KF lowered cook yield ～1% and slightly reduced sensory panel and texture profile analysis texture values. KF gel incorporated at 10% had similar properties to a control low-fat desinewed lamb sausage, while KF at 20% could reduce "toughening" in low-fat sausage products. Use of konjac gel as a fat mimetic could reduce total caloric energy by replacing a portion of the meat in a sausage formulation.     

Potential of thermophilic amylolytic bacteria for growth in unconventional media: Potato peels

Extremozymes have gained high level of popularity for their industrial relevance. In this regard four thermophilic bacterial isolates were isolated from hot spring Chakwal in Pakistan. All the strains were screened for amylolytic activity by producing zone of clearance on starch agar plates. The bacterial isolates were cultivated employing potato peels as major energy source. All the four bacterial strains were Gram positive, motile, endospore formers and were positive for catalase and oxidase tests. Phylogenetic analysis based on 16S rRNA sequences confirmed that all the strains were belonged to the Bacillus licheniformis with 98–99% similarity under Accession numbers KF424263, KF424264, KF424265, and KF424266 for KA2, KA5, KA6, and KA9, respectively. The pH, temperature, oxygen requirement, and inocula size of the medium were optimized, which could yield amylase up to 0.61 U while growing in potato peels based media. Besides being thermostable, the enzymes have a working pH range of 5–9. The isolate KA2 showed maximum threefold purification, and percentage yield was estimated to be 93.06% as compared to crude enzyme. They yielded enough protein suggesting their potential in industrial applications in unconventional and economical substrate.

Practical applications

Amylases produced in this study could be utilized in starch hydrolysis for the production bioethanol and can be employed in different industries like food, paper, and detergent for various purposes. In addition, production of efficient amylases resolves the waste management problem of agro‐industrial waste of potato peels.     

Konjac flour improved textural and water retention properties of transglutaminase-mediated,heat-induced porcine myofibrillar protein gel: Effect of salt level and transglutaminase incubation

Functional properties of heat-induced gels prepared from microbial transglutaminase (TG)-treated porcine myofibrillar protein (MP) containing sodium caseinate with or without konjac flour (KF) under various salt concentrations (0.1, 0.3 and 0.6 M NaCl) were evaluated. The mixed MP gels with KF exhibited improved cooking yields at all salt concentrations. TG treatment greatly enhanced gel strength and elasticity (storage modulus, G′) at 0.6 M NaCl, but not at lower salt concentrations. The combination of KF and TG improved the gel strength at 0.1 and 0.3 M NaCl and G′ at all salt concentrations, when compared with non-TG controls. Incubation of MP suspensions (sols) with TG promoted the disappearance of myosin heavy chain and the production of polymers. The TG-treated MP mixed gels had a compact structure, compared to those without TG, and the KF incorporation modified the gel matrix and increased its water-holding capacity. Results from differential scanning calorimetry suggested possible interactions of MP with KF, which may explain the changes in the microstructure of the heat-induced gels.     

磁性固体碱催化剂KF/Fe3O4催化大豆油酯交换制备生物柴油

采用浸渍法制备磁性固体碱催化剂KF/Fe3O4,并用于大豆油酯交换制备生物柴油的反应。采用单因素试验,考察催化剂的焙烧温度、KF的负载量、醇油摩尔比和催化剂的用量等因素对催化剂性能的影响,并对催化剂进行了XRD表征。结果表明:当焙烧温度为400℃、KF的负载量为30%、醇油摩尔比为10∶1、催化剂用量占大豆油质量的4%时,生物柴油的产率达91.16%。该催化剂具有较好的重复使用性能,重复使用5次后生物柴油的产率仍达80%以上。     

Screening and enumeration of lactic acid bacteria in milk using three different culture media in Petrifilm Aerobic Count plates and conventional pour plate methodology

This study aimed to compare Petrifilm Aerobic Count (AC) plates and the conventional pour plate methodology using de Mann-Rogosa-Sharpe (MRS), Kang-Fung (KF) and Kang-Fung-Sol (KFS) culture media for screening and enumeration of lactic acid bacteria (LAB) in milk. Suspensions of 10 LAB species in reconstituted powder skim milk and 30 raw milk samples, without experimental inoculation, were tested. For selective enumeration, all samples were previously diluted in MRS, KF and KFS broths and then plated in Petrifilm AC and conventional pour plate methodology, using the same culture media with added agar. All plates were incubated at 37 degrees C for 48 h in anaerobic conditions. Differences in the counts were observed only for raw milk samples using KFS in conventional methodology, when compared with the counts obtained from MRS and KF (P0.05). The results showed excellent correlation indexes between both methodologies using the three culture media for LAB suspensions (r=0.97 for MRS, KF and KFS). For raw milk samples, the correlation indexes were excellent (r=0.97, for MRS) and good (r=0.84 for KF, and r=0.82 for KFS), showing some interference in Petrifilm AC when supplements were added, especially lactic acid. These results indicate the possibility of using Petrifilm AC plates for enumeration of LAB in milk, even with the use of selective supplements.