煮茧工艺经验谈

对多年从事的煮茧工作进行经验总结,调强了煮茧的重要性,论述了真空渗透热处理煮茧的要领,对生产中几种不同原料的煮茧方法进行了分析,并对触蒸工艺提出了见解,对生产实践具有一定的参考价值.     

己酸菌筛选新途径及工艺参数正交试验

采用加大琼脂用量制成固体斜面培养基，以稀释分离，真空培养的方法进行己酸菌分离纯化，并采用正交试验法对己酸菌的生长繁殖条件进行了探讨，其影响因素依次为酒度,pH值，培养时间，培养温度及热处理温度，优化因子为pH6，酒度2％，热处理温度80℃，培养温度30℃，培养时间6d。     

热处理对实木地板尺寸稳定性影响的研究

探讨热处理对两种实木地板坯料尺寸稳定性的影响,结果表明,真空热处理的板材抗膨胀率明显高于常压热处理板材的抗膨胀率。     

深冲成型用TA1钛带热处理工艺研究

文章主要以深冲成型用钛带为代表,通过工艺试验,比较常规时间大气退火、长时间真空退火、氩气保护连续退火等不同热处理方式与制度的性能参数,冲压情况。结果表明:常规时间大气退火的最佳热处理制度是750℃/30min;长时间真空退火的最佳热处理制度是650℃/10h;氩气保护连续退火的最佳热处理制度是780℃/10min;深冲成型用钛带的最佳热处理方式是氩气保护连续退火。     

真空热处理技术及其应用

本文介绍了真空热处理的若干技术问题，并描述了它在模具热处理中的应用，显示了它所具有的优越性。     

真空热处理、可控气氛热处理在钢丝生产中的应用

真空热处理有４大作用，使处理的钢丝具有光亮的表面；多种的可控气氛热处理可保护钢丝，防止钢丝表面发生化学反应。合理选用热处理方式将确保产品的高质量。     

真空热处理落叶松木材动态粘弹性的研究

为了揭示真空热处理温度与时间对落叶松木材动态粘弹性的影响,以落叶松木材为研究对象,分别在160℃、200℃和240℃的条件下对其进行真空热处理4h,在200℃的条件下对其进行真空热处理2h、6h、10h。利用动态粘弹性分析仪测试了未处理材与热处理材在温度30~300℃范围内,测试频率1Hz条件下的动态粘弹性。结果表明:随着测试温度的逐渐升高,未处理材与热处理材的储存模量均呈下降的趋势,损耗模量呈现先升高后下降的变化趋势;在相同的测试条件下,热处理木材的储存模量均高于未处理材的储存模量;随着热处理温度的升高和热处理时间的延长,木材的储存模量逐渐增大;在测试的温度范围内,可以观察到2个力学松弛过程,热处理木材的α力学损耗峰温度高于未处理材的α力学损耗峰温度,热处理后木材的β力学损耗峰强度降低。     

饲料制粒机环模的真空气淬热处理工艺

对饲料制粒机环模的真空气淬工艺,从热处理设备的选用、工艺参数的设置、气淬冷却介质的比较及变形量的控制等多个方面进行了分析和讨论.根据以往的实践经验,针对此工艺中可能会出现的问题提出了相应的解决方案,并给出了一些有用的工艺参数值以供参考.     

超声波热处理对真空包装泡椒猪肝质构特性的影响

实验探讨超声波热处理对真空包装泡椒猪肝硬度、胶黏性、咀嚼性和弹性等质构特性的影响。结果表明:超声强度在126~162W/m~2、超声时间在15~25 min、热处理温度在60~70℃、真空处理时间在40~60 s、料液比在1:3~1:5(m/V)范围内,超声波热处理对真空包装泡椒猪肝质构特性有较佳的改善作用,且产品质构特性与各工艺参数问有良好的相关性。通过L_(16)(3~5)正交试验证实超声强度、热处理温度、真空处理时间、超声时间是影响真空包装泡椒猪肝质构特性的关键因素;超声强度、热处理温度、真空处理时间对泡椒猪肝质构特性的影响达到极显著水平(P0.01);超声时间对泡椒猪肝质构的影响达到显著水平(P0.05);料液比对泡椒猪肝质构影响不显著;最佳工艺参数为:超声强度为144W/m~2、超声时间为15 min、热处理温度为65℃、真空处理时间40 s、料液比1:5(m/V)。     

多用炉热处理渗碳工艺及应用分析

随着工业自动化的飞速发展,多用炉热处理渗碳工艺得到广泛应用。文章就曲柄热处理工艺的试制过程进行研究,对设备和数据进行分析,探讨多用炉热处理渗碳工艺技术的加工效果达到理想水平的方法,为企业创造了效益。工件进行炉热处理的过程主要为渗碳、淬火后再进行磨削加工,同时要求磨削后产品硬度符合工艺及使用要求。文章笔者就曲柄热处理工艺的试制过程作为论点,围绕试制过程中,曲柄的扭矩、过盈量、硬度、耐磨度、韧性等情况,对炉热处理渗碳工艺应用进行分析。     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Encapsulation of food ingredients

Microencapsulation is a relatively new technology that is used for protection, stabilization, and slow release of food ingredients. The encapsulating or wall materials used generally consist of starch, starch derivatives, proteins, gums, lipids, or any combination of them. Methods of encapsulation of food ingredients include spraydrying, freeze‐drying, fluidized bed‐coating, extrusion, cocrystallization, molecular inclusion, and coacervation. This paper reviews techniques for preparation of microencapsulated food ingredients and choices of coating material. Characterization of microcapsules, mechanisms of controlled release, and efficiency of protection/ stabilization of encapsulated food ingredients are also presented.     

Prediction of worst case migration: presentation of a rigorous methodology

An improvement of the Piringer model, allowing the prediction of a worst case migration from packaging to food is presented here. The authors are proposing other constants for the calculation of the upperbound value of the diffusion coefficient, using experimental data determined by a film to film method. Considering the plasticizing effects of food simulants, a model involving the variation of the diffusion coefficient versus space and time must be used. Future fields of investigation are discussed: the relationship between diffusion coefficients and the volume of the migrant (instead of molar mass), and the variation of diffusion coefficient activation energy with temperature.     

Original semiologic standardized evaluation of stratum corneum hydration by Diagnoskin stripping sample

In a normal and healthy skin, the regular elimination of the superficial corneocytes, called desquamation, is a fundamental physiologic process intended to protect the barrier function of the skin. This invisible loss of corneocytes, individually or in small groups, is incessantly compensated by the divisions of the proliferative layer and the upward cellular maturation in order to maintain the harmonious renewal of the epidermis and the integrity of the stratum corneum. The harmony of this desquamation process is intimately conditioned by a sufficient hydration of the stratum corneum: (i) an abnormal desquamation leads to a disruption of the water barrier function and consequently to a dehydration tendency of the stratum corneum, and (ii) a cutaneous dryness (whatever the cause) is able to disturb the desquamation process. Protecting the water content of the stratum corneum has always been a major preoccupation of the cosmetic industry scientists. Consequently, the moisturizing properties of a cosmetic product are objectively measured by various explorations directly targeted on the hydration (corneometry) and on the level of the water barrier function (transepidermal water loss (TEWL) measurements), which depends directly on the skin hydration state. This intimate linkage of the desquamation process and the water content of the stratum corneum enable us to suggest an indirect assessment of the hydration from a direct study of the desquamation by examining a skin-stripping sample (D-Squames) by an optical microscope (linked to a computer). We will describe this already known technique and mainly its new and unpublished semiologic exploitation, named Diagnoskin, whose advantages are its simplicity and its reproducibility particularly interesting in the case of sequential appraisal of dermatologic or cosmetic treatments.     

Peptides from milk proteins and their properties

This review has attempted to study the literature pertaining to peptides derived from milk proteins. Hydrolysis of milk proteins to generate peptides has been practiced for a long time and it was recognized early on in this process that the taste of hydrolyzates might hinder use of these products in food formulations. Modification of protein is necessary to form a more acceptable or utilizable product, to form a product that is less susceptible to deteriorative reactions and to form a product that is of higher nutritionall quality. Modifications may be achieved by a number of chemical and enzymatic means. This review has considered only enzymatic modification of dairy proteins. Modified proteins contain peptides and some of these peptides have been purified and their functionalities have been compared with unmodified proteins. This paper has examined the literature pertaining to improvement in functionality of enzyme-modified proteins. Improvements in solubility, emulsification, foaming and gelation were examined. There is limited information available on the sequence of the peptides necessary to improve the functional characteristics of proteins. Knowing the sequences of desirable functional peptides can lead to genetic alteration of proteins to improve functionality. Addition of synthetic peptides to intact proteins may be another way in which the functionality of proteins can be augmented. Some of the peptides in milk proteins are capable of affecting biological functions of an organism. These effects can be antimicrobial and probiotic, i.e., prevent the growth and proliferation of undesirable and pathogenic organisms, or they may promote the growth of desirable bacteria in the digestive tract of humans and animals. Peptides derived from milk protein have been shown to exert digestive and metabolic effects as well. They may also influence the immune system. These biological effects may play an important role in the development of medical foods that treat or mitigate the effects of diseases. Proteins are allergens and therefore it is possible that products derived from modification of proteins may also be allergens. The known literature about the allergenicity of peptides derived from milk proteins has been examined in this article. Last, but not the least, the taste attributes of peptides is also considered. Bitterness of hydrolyzates is a common occurrence and the origins of these bitter peptides and possible ways of mitigating this sensory defect has been discussed. Many of the peptides that enhance functionality and exert biological activity are likely to be bitter. Therefore, the bitter taste of hydrolysis products has to be dealt with in boosting the functional or nutraceutical aspects of foods containing these peptides. Analytical techniques for sequencing peptides have become more accessible and purification of peptides is commercially feasible. Computer based modeling techniques have aided the prediction of structures in these peptides. These advances, coupled with the advances in biotechnology, promise to revolutionize the future of nutraceutical and functional foods.     

Tailoring fatty food simulants made from solvent mixtures (1): comparison of methanol, ethanol and isopropanol behaviour with polystyrene

To investigate the use of solvent mixtures as test media replacing olive oil in migration tests, the interaction of polystyrene with mixtures composed of various amounts of tert.butyl acetate (mimicking the ester functions of oil) and of a low molecular weight alcohol (methanol, ethanol and isopropanol as inert co-solvent) was studied, using FTIR. Isopropanol, which has a lesser tendency to form hydrogen bonds in the plastic, can be used as main component of alternative fatty test media, its aggressiveness to polystyrene being tailored by adjusting the concentration of tert.butyl acetate. Concentrations below 20% seem useful on the basis of the mechanism of displacement of the alcohols.     

古贝春酒中的呈香呈味物质GC-MS分析研究

利用闻香,结合气相色谱-质谱仪分析方法对古贝春白酒中的各种香味成分进行定性和定量分析。结果表明,定性、定量出70多种风味化合物,包括25种酯类、13种酸类、10种醇类、5种醛类、1种酮类、10种芳香族及酚类、5种呋喃类、2种吡嗪类、2种缩醛类物质和1种硫化物。(晓文)