NT—90型保鲜机在食品冷藏中的应用

食品的腐败变质主要是由于微生物的生长繁殖所致。作为防止食品腐败的技术,目前主要是冷藏、真空包装、辐射和药物防霉等。冷藏虽可抑制微生物的生长繁殖,甚至可以杀灭某些微生物,但对嗜冷性微生物如霉菌和酵母菌,即使在—8℃下孢子仍能萌发,因此冷库极有必要配备能杀灭包括嗜冷性微生物在内的专用保鲜设备。     

农产品无菌真空热包装生产线研制

一、立项的背景和意义 传统食品及农产品在真空包装后要进行二次杀菌,其目的是为了杀灭因真空包装引入的二次污染细菌,延长食品或者农产品的货架期。二次杀菌基本采用对包装产品进行蒸煮的方法,这种方法沿用多年,食品的货架期基本能得到保障,目前大多数食品及农产品仍然采用这种加工工艺,例如东坡肉、甜玉米、道口烧鸡等。但是在这种公认成熟的工艺中,仍然存在着一些弊端,主要有三：一是食品的安全问题,二是食品的营养损失问题,三是能源重复消耗问题。     

解码食品真空包装机械及其应用趋势

真空包装机械能够自动抽出装满食品的真空包装袋内的空气,达到预定真空度后完成封口工序.亦可再充入氮气或其它混合气体,然后完成封口工序.真空包装机常被用于食品行业,因为经过真空包装以后,食品能够抗氧化,从而达到长期保存的目的.根据食品真空包装机械行业的发展前景,分析了食品真空包装机械的工作原理及性能特点,介绍了真空包装机械在食品行业中的应用实例,同时指出了食品真空包装机械的发展趋势.     

真空包装气体含量验证方法及“松包”问题的分析

真空包装的气体残留一直是困扰相关企业的包装难题。对于尚未出厂的真空包装产品,可以通过文中所介绍的压差法和液位分析相结合的方法进行无损检测和控制,效果显著。但对于储藏和销售环节的真空包装产品来说,"松包"问题的影响更为严重,建议相关企业从真空包装材料、内容物及其加工过程综合分析,方能从根本上解决"松包"问题。     

台湾发布真空包装食品的标签法规

“真空包装食品良好卫生规范” 近来,台湾发布真空包装食品的标签等法规,其中“真空包装食品良好卫生规范”适用于真空包装即食食品的相关食品业者。     

如何保证真空包装机良好的抽气效果

<正>产品进行收缩包装时必须对包装膜内的空气进行抽空,使被包装产品内达到真空状态,这样有利于商品的长期保存。但有时真空包装机如果产生一些故障或者操作不当等一些原因也容易造成抽气效果不佳,值得引起重视。真空包装机是采用真空包装膜对产品进行真空包装,所以对于真空包装膜的质量控制尤为关键。必须采用质量合格并且具有一定厚度的真空包装膜,在使用前的保存过程中和使用中的包装     

包装材料透气性能测试方法的研究与探讨

一、概述中国是食品生产和出口大国 ,如何对食品进行包装是人们研究的一个重要课题 ,保护食品质量、维持食品新鲜是食品包装最重要的功能。随着科技的发展、社会的进步 ,真空包装、充气包装、无菌包装、气调包装等包装方法相继出现 ,大大地延长了食品的保质期、保鲜期 ,同时对包装材料的透气性能也提出了较高的要求。包装的食品不同 ,采用的包装方法不同 ,对包装材料的透气性能也有不同的要求。例如 :对熟肉制品 ,为防止其变质 ,多采用真空包装 ,对某些蔬菜、水果 ,为了延长其保鲜期以利于长途运输和长期保存 ,常采用充气包装、气调包装 ,这…     

《食品真空存贮与保鲜工艺》讲座（七）

《食品真空存贮与保鲜工艺》讲座（七）刘玉魁（兰州物理研究所，兰州７３００００）第七讲真空包装材料７．１对包装材料的要求真空包装材料性能，直接影响食品的存贮寿命及风味的变化，在进行真空包装和充气包装时，除正确选择包装手段及气体组分外，选择好包装材料亦是...     

键合型纳米银-腈纶纤维的制备及其抗菌性质

用部分偕胺肟化的腈纶纤维与硝酸银溶液反应,使纤维表面络合上银离子,再用甲醛溶液还原Ag(Ⅰ)成金属Ag,得银复合腈纶纤维。控制AgNO3浓度,可得到银粒尺寸在纳米级的纳米银复合腈纶纤维(Ag—PAN)。用IR光谱和SEM进行表征。对Ag-PAN进行抗菌实验,结果显示：Ag—PAN对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌有很强的杀灭作用,Ag含量达0．8％的Ag-PAN对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌的杀灭率超过99．99％。Ag含量迭1．3％时,Ag-PAN对3种菌的杀灭时间均在0．5h以内。     

复合气调保鲜包装机的原理

复合气调保鲜包装机是在真空包装机、充氮包装机的基础上研发的一种全新的食品果蔬保鲜包装设备.其最大特点是解决了真空包装加高温灭菌后食品口感品味破坏较大、充氮包装要求无菌包装而投资较大的欠缺.通过复合气调包装,能确保食品原有口感、口味,保证了食品的原汁原味、原貌.     

Modelling transport phenomena in refrigerated food bulks, packages and stacks: basics and advances

Transport phenomena, comprising airflow, heat and mass transfer, are key processes in refrigerated storage. This paper gives a review of approaches to modelling transport phenomena in food bulks, packages and stacks. Darcy–Forchheimer porous media models have been successfully used. Ergun theory was found not directly applicable when foods are stored in packages, which cause flow confinement and vent hole resistance, invalidating traditional theory. Heat and mass transfer in food bulks has been modelled using single- and two-phase models. Suggested modifications were demonstrated to not be generally valid, leaving much scope for further development of models for refrigerated system design. Direct CFD approaches were shown to be successful alternatives to achieve this goal.     

连续冻结隧道的冻结时间分析及其对能耗的影响

冻结时间影响速冻食品的质量和能耗 ,本文通过对冻结时间的编程计算 ,并针对不同的隧道冷却介质温度、隧道吹风速度和不同的食品厚度情况下的冻结时间进行分析比较 ,得出根据冻结时间来选择设备的运行工况 ,既可以节能 ,又可以使装置得到最合理使用的结论     

淀粉冻融特性及其品质影响因素研究现状

目的 针对反复冻融对淀粉质食品组织具有破坏作用,融化后产品水分会损失且质地易软化,造成品质下降、消费属性降低等现象,总结和研究该现象的机制和相关影响因素。方法 对淀粉在冻融过程中的老化回生、硬度上升、析水率提高等品质劣变问题,以及影响冻融稳定性的重要因素进行探讨。结果 淀粉来源,直链与支链淀粉含量,盐、糖的加入等均会对淀粉冻融稳定性造成影响,但具体效果受环境因素影响程度较大,有待进一步探究。结论 阐述了影响淀粉基食品冻融稳定性的重要因素,探究其可能的作用过程和机理,为含淀粉质食品的品质改良途径提供理论依据。     

Refrigeration throughout the world

The economic impact of refrigeration technology throughout the world is already very impressive, and more significant than is generally believed. While the yearly investment in machinery and equipment may approach US$100 billion, the value of products treated by refrigeration is perhaps ten times this amount. The importance of refrigeration is bound to increase since it will be an essential factor in solving two major problems of the future: the supply of enough food and the development of new energy sources. The use of low temperatures constitutes a major means of conservation of perishable foods during storage and distribution and it is widely applied in the developed countries. In the Third World, however, the use of low temperatures is mainly limited to food for export and the needs of the ‘well-to-do’ sector of the population. Refrigerated or frozen foods, in their present form, are generally priced too high for the undernourished poor. There is a pressing need for simple and inexpensive cooling methods to enable efficient low cost mass production and distribution under more primitive conditions. The future of man, and his food supply in particular, depends on the availability of sufficient energy. At present, fossil fuels carry the main load, but in the course of the next century new energy sources, such as nuclear fusion, will have to be commissioned. Refrigeration technology will play an important part in this development.     

自热食品及自热包装研究进展

目的文中对目前自热食品的研究进展进行总结研究,并针对其存在的问题进行讨论。方法综述目前自热食品的包装形式(双层罐式、分体加热式、一体加热式及水浴加热式)的研究进展,并对自热食品的发展历史进行介绍,根据国内自热食品近年来的发展现状,对自热包装现阶段存在的问题进行分析,并指出自热食品未来的发展趋势。结果目前自热食品难以满足加热过程中热量的释放与传导,还未能达到短时升温、顺应市场需求、生产多种类自热食品等条件,在一定程度上限制了自热食品的市场规模。结论自热食品的放热剂、包装材料的选择,以及自热食品的种类创新与营养改善将成为未来自热食品的研发重点。     

解读2017年日本进口食品监控检查指导计划

本文主要分析了2017年度日本进口食品监控指导计划的主要内容,作为政府食品主管部门管理出口食品的依据,企业规避贸易风险的重要参考.     

Heat transfer coefficients for forced-air cooling and freezing of selected foods

To maximize the efficiency of cooling and freezing operations for foods, it is necessary to optimally design the refrigeration equipment to fit the specific requirements of the particular cooling or freezing application. The design of food refrigeration equipment requires estimation of the cooling and freezing times of foods, as well as the corresponding refrigeration loads. The accuracy of these estimates, in turn, depends upon accurate estimates of the surface heat transfer coefficient for the cooling or freezing operation. This project reviewed heat transfer data for the cooling and/or freezing of foods. A total of 777 cooling curves for 295 food items were obtained from an industrial survey and a unique iterative algorithm, utilizing the concept of ‘equivalent heat transfer dimensionality’, was developed to obtain heat transfer coefficients from these cooling curves. Nine Nusselt–Reynolds–Prandtl correlations were developed from a selection of the 777 heat transfer coefficients resulting from this algorithm, as well as 144 heat transfer coefficients for 13 food items, collected from the literature. The data and correlations resulting from this project will be used by designers of cooling and freezing systems for foods. This information will make possible a more accurate determination of cooling and freezing times and corresponding refrigeration loads. Such information is important in the design and operation of cooling and freezing facilities and will be of immediate usefulness to engineers involved in the design and operation of such systems.     

食品营养标签分析的标准物质研究

提高测量精确性可以保证食品营养标签提供食品营养可靠可知性和产品质量,是提高食品营养质量评价的重要手段。食品营养成分标准物质可保证测量有效性,是验证营养标签分析方法和实验室内分析的质量保证所必需的,对营养标签标准和标签法具有支持和推动作用。阐述了我国和美国食品营养分析标准物质,并介绍了美国AOAC作为发展一系列基于蛋白质、脂肪和碳水化合物的代表所有食品标签分析的标准物质的食品三角形模式图。     

The Effect of Active Packaging on Minimizing Food Losses: Life Cycle Assessment (LCA) of Essential Oil Component‐enabled Packaging for Fresh Beef

Packaging plays an important role in ensuring food safety and quality, and the development of active packaging, especially antimicrobial packaging, enables actively inhibiting/killing the microorganisms causing food spoilage and thus extending the product's shelf life. A survey of the publications revealed that generally 50% shelf life extension is possible. The goal of this study is to assess the overall environmental performance of the food and packaging system considering the effect of food loss reduction by using active packaging. A comparative life cycle assessment has been carried out, focusing on a case study: essential oil component‐enabled packaging for fresh beef. Different scenarios were set up to contrast the situations of food using conventional packaging (current situation) and food using novel active packaging (containing active coating). Additionally, a sensitivity analysis has been integrated, aiming to identify the breakeven point of the balance. In the scenarios using the best‐performance active packaging, it was shown that a breakeven point can be achieved across the four impact categories evaluated, including global warming, fossil energy demand, acidification potential and eutrophication potential. It is expected that the obtained results would serve as guidelines for active packaging development striving for a positive eco‐profile of the food and packaging system. Copyright © 2015 John Wiley & Sons, Ltd.     

Use of simple thermal conductivity models to assess the reliability of measured thermal conductivity data

Thermal conductivity data are important for modelling thermal processes and designing refrigeration systems. The literature contains a large number of data for food products, but many are questionable, whether due to typographical errors during publication, indirect measurement methods or inherent variability in the properties of the food itself. This paper describes a method by which the reliability of thermal conductivity data can be checked using simple thermal conductivity models and basic heat transfer theory, provided composition data for the foods are available, or may be assumed based on foods with similar composition. The method is applied to a variety of foods to serve as worked examples. It is recommended that these models be used to check the credibility of measured data before they are published, and also to check published data before they are used in any calculations.