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食品贮藏保鲜技术论文英文版怎么写

发布时间:2024-07-11 16:12:32

食品贮藏保鲜技术论文英文版

食品冷藏的原理及技术要点  冷藏又称低温贮藏,是指在0℃或略高于食品冰点的低温环境条件下,对食品进行贮藏的方法。冷藏是通过抑制微生物及酶类的活动和降低食品基质中的活性,来防止食品腐败变质,保持食品的新鲜度和营养价值。冷藏是目前效果较好、价格较低、保鲜时间校长、最普遍采用的食品贮藏方法。  一、食品的冷藏原理  食品的腐败变质,主要是由于微生物的生物活动和食品中的酶所进行的生物化学反应所造成。动物性食品,如禽、畜、鱼等在贮藏时很容易被细菌污染,细菌并很快繁殖,从而造成食品的腐败。但是微生物的繁殖和酶活性的发挥,都需要适当的温度和水分条件;环境不适宜,微生物就会停止繁殖甚至死亡,酶也会丧失催化能力,甚至被破坏。把动物性食品放在低温条件下就可抑制微生物的繁殖和酶对食品的作用,可以贮藏较长时间而不会腐败变质。  对于植物性食品,腐败的原因是呼吸作用。水果、蔬菜在采摘后虽然不能继续生长,但它们仍是一个有机体,仍然有生命,有呼吸作用。低温能够减弱果蔬食品的呼吸作用,延长它们的贮藏期限。但温度不能过低,否则会引起植物性食品的生理病害,甚至冻死。因此植物性食品冷藏温度应该选择接近其冰点但又不致使植物发生冻死现象为宜。  二、冷藏库的建造要求  1、隔热层的隔热性能要好。隔热层的隔热性能越好,耗冷量越小,所引起的库温波动也就越小,从而有利于贮藏物的质量保持,延长贮藏时间,减少贮藏物的干缩损耗,同时可以节省制冷设备的投资和运转费用。  2、注意隔热层外侧的防潮。冷库围护结构两侧的温度不一致,易形成水蒸气分压差,伴随热量的传递,库外的水蒸气就会向库内渗透,故应设置防潮隔气层。常见的防潮方法有3种:沥青防潮、塑料薄膜防潮及使用金属夹心板兼作防潮层。  3、安装良好的抽气系统。食品在冷库内贮藏一定时间后易积累二氧化碳、乙烯等气体物质,故需安装良好的抽气系统,以便经常换入新鲜空气,以利于食品的贮藏保鲜。  4、选择合适的制冷系统。冷库是通过人工制冷的方法来获取冷量的。目前常用液体气化制冷法或蒸气制冷法。蒸气制冷法可分为压缩式、吸收式、喷射式3种制冷方式,其中以压缩式最为广泛。压缩式制冷机主要由压缩机、冷凝器、调节阀和蒸发器4部分组成,它是一个闭合循环系统。  三、冷藏时应注意的一些问题  1、预冷。预冷是食品在长途运输或冷藏前预先进行的一种冷却方法,其要求是将待贮食品快速降至规定温度。它是维护被运输食品的品质和延长贮藏寿命的重要措施。预冷通常在冷库和预冷间进行。常用的预冷方法有自然空气冷却、通风冷却、真空冷却及冷水冷却。经预冷处理后的食品应迅速置入低温环境中贮藏。  2、温度允许的变化范围与贮藏期限。冷藏库中的温度并不可能恒定在某一温度值上,因制冷机性能、库容大小和内外温差等因素会使库温在一定范围内波动。一般而言,食品以贮藏温度较低,且变化范围越小越好。这样有利于食品保鲜,防止损耗及低温生理病害。  3、温度的控制。不同的食品具有不同的最适冷藏温度。冷库温度和入库后食品的温度受多种因素的影响,如入库时食品的温度与库温的差别、制冷机的效能与库容、库内空气流通情况、堆码方式,食品品种及成熟度等。入库时应合理堆码,根据实际情况调节库温;出库前需采用逐步升温方法,以免因内外温差大,而造成食物表面凝结水珠。  4、湿度的控制。冷库常因蒸发器大量吸热而不断地在其上结附冰霜,又不断地将冰霜融化流走,致使库内湿度常低于食品贮藏对湿度的要求。可以采用增大蒸发器面积、减少结霜,安装喷雾设备或自动喷湿器来调节冷库内湿度。另外,当因货物出入频繁,使库内相对湿度增大时,可安装吸湿器吸湿,并加强冷库管理,严格控制货物和人员的频繁出入。

research about the skill of how food keep freshingand the trend of it development自己翻译的,希望对你有帮助

栅栏技术应用于食品保藏是德国肉类研究中心Leistner(1976)提出的,他把食品防腐的方法或原理归结为高温处理(F)、低温冷藏(t)、降低水分活度(Aw)、酸化(pH值)、降低氧化还原电势(Eh)、添加防腐剂(Pres)、竞争性菌群及辐照等因子的作用,将这些因子称为栅栏因子(hurdle factor)。国内也有将栅栏技术和栅栏因子相应译为障碍技术和障碍因子。影响食品稳定性的微生物主要是细菌、酵母和霉菌,这些微生物的生长、繁殖都要求有最底限度的水分活度。如果食品的水分活度低于这一要求,微生物的生长、繁殖就会受到抑制。在水分活度底于60时,绝大多数微生物就无法生长。部分微生物生长必需的最低水分活度(aw值)最低Aw值 细 菌 酵 母 菌 霉 菌0.96 假单孢杆菌(Pseudomonas) 0.95 沙门氏菌(Salmonella)埃希氏杆菌(Escherichia)芽孢杆菌(Bacillus)梭状芽孢杆菌(Clostridium) 0.90 0.88 0.85 0.62 接合酵母(Zygosaccharomyces) 0.60 耐干霉菌(Xeromyces)CO2在食品包装中的应用 最近,美国专家采用新技术,用CO2制塑料包装材料。即使用特殊的催化剂,将CO2和环氧乙烷(或环氧丙烷)等量混合,制成新的塑料包装材料,其特点具有玻璃般的透明度和不通气性;类似聚碳酸酯和聚酰胺树脂;在240℃温度下不会完全分解成气体;有生物分解性能不会污染环境与土壤等特点。 我国已研究成功利用纳米技术,高效催化CO2合成可降解塑料。即利用CO2制取塑料的催化剂“粉碎”到纳米级,实现催化分子与CO2聚合,使每克催化剂催化130克左右的CO2,合成含42%CO2的新包装材料。其作为降解性优异的环保材料,应用前景广阔。氮气在食品包装中的应用 氮气(N2)是理想的惰性气体,在食品包装中有特有功效:不与食品起化学反应与不被食品吸收,能减少包装内的含氧量,极大地抑制细菌、霉菌等微生物的生长繁殖,减缓食品的氧化变质及腐变,从而使食品保鲜。充氮包装食品还能很好地防止食品的挤压破碎、食品粘结或缩成一团,保持食品的几何形状、干、脆、色、香味等优点。目前充氮包装正快速取代传统的真空包装,已应用于油炸薯片及薯条、油烹调食品等。受到消费者特别是儿童、青年的喜爱,充氮包装可望应用于更多的食品包装。复合气体在包装食品中的应用 复合气调保鲜包装国际上统称为MAP包装,所用的气调保鲜气体一般由CO2、N2、O2及少量特种气体组成。CO2能抑制大多需氧腐败细菌和霉菌的生长繁殖;O2抑制大多厌氧的腐败细菌生长繁殖;保持鲜肉色泽、维持新鲜果蔬富氧呼吸及鲜度;N2作充填气。复合气体组成配比根据食品种类、保藏要求及包装材料进行恰当选择而达到包装食品保鲜质量高、营养成分保持好、能真正达到原有性状、延缓保鲜货架期的效果。 Fence technology for food preservation is the German Research Center for meat Leistner (1976), and his approach to food preservation, or the principle of attributed to high temperature treatment (F), low-temperature refrigeration (t), reduced water activity (Aw), acidification (pH value), reduced redox potential (Eh), add preservatives (Pres), competitive factors, such as bacteria and the role of radiation, these factors will be known as the fence factor (hurdle factor) There are also technical and fence fence will factor into the corresponding technical obstacles and barriers The stability of the impact of food micro-organisms mainly bacteria, yeast and mold, the growth of these micro-organisms, reproduction require a minimum water If the food is lower than the requirements of water activity, microbial growth, reproduction would be At the end of the 60 water activity, the vast majority of micro-organisms can not The growth of some micro-organisms necessary minimum water activity (aw value) Aw value of the minimum bacterial yeast fungi 96 Pseudomonas (Pseudomonas) 95 salmonella (Salmonella) bacteria Escherichia coli (Escherichia) Bacillus (Bacillus) Clostridium (Clostridium) 90 88 85 62 bonding yeast (Zygosaccharomyces) 60 mold-resistant dry (Xeromyces) CO2 in the food packaging applications Recently, the US experts to utilize new technologies, CO2 system using plastic packaging That is, the use of special catalyst, the CO2 and ethylene oxide (or propylene oxide) mixed contour, made of new plastic packaging materials, characterized with a glass-like transparency and non-aeration; similar to polycarbonate and poly acid amine resin; 240 ℃ in temperature will not be completely broken down into gas; are not biodegradable properties, such as pollution of the environment and soil China has studied the success of the use of nano-technology, highly efficient catalytic synthesis of biodegradable plastics CO Namely, the use of CO2 a catalyst for making plastics "crush" to nano-scale, the achievement of CO2 molecules and polymerization catalyst to catalyst per gram to about 130 grams of CO2, synthesis of 42% CO2 with a new packaging Outstanding as the environmental degradation of materials, the application of a broad Nitrogen in food packaging applications Nitrogen (N2) is the ideal inert gas, in food packaging are unique to the effectiveness of: No chemical reaction with the food from the food and not be absorbed to reduce the oxygen content of the package, which greatly inhibit bacteria, mold and other microbial growth and reproduction and slow down the oxidative deterioration of food and become rotten, so that fresh Nitrogen also good foods to prevent food extrusion broken or curled Food bonding to maintain the geometry of food, dry, crisp, color, smell and so Nitrogen current packaging is rapidly replacing traditional vacuum packaging had been used for frying potato chips and French fries, cooking oil and other By consumers, especially children, young people love, Nitrogen packaging is expected to apply more food Composite gas in food packaging applications Modified Atmosphere Packaging composite international collectively referred to as MAP packaging, used in modified atmosphere gas in general by the CO2, N2, O2 and a small amount of the composition of specialty CO2 can inhibit the aerobic corruption most of the growth of bacteria and mold breeding; O2 inhibited most of the growth of anaerobic bacteria breeding corruption; to maintain the color of fresh meat, fresh fruits and vegetables to maintain freshness breathing and oxygen-rich; N2 gas for Complex gas composition ratio based on food type, preservation requirements and select appropriate packaging materials to achieve high-quality fresh foods, maintain good nutrition, the original characters can really slow down the effect of shelf-life

近年来,国内外果蔬贮藏保鲜技术发展很快,其中采用降温、降氧、控制二氧化碳及乙烯含量的气凋贮藏保鲜技术应用较为广泛。现将果蔬贮藏保鲜技术的原理、方法及发展前景做一介绍。

食品贮藏保鲜技术论文英文版怎么写

食品科学与工程专业分为畜产品加工、发酵技术、园产品加工三个方向,培养具有食品生化、食品化学、食品(畜产品、发酵食品、园产品)加工、检验等技术知识。

Food preservation technology research and development trends

The Current Status and Development Trend for the study of Food Preservation Technique

食品贮藏保鲜技术论文英文版格式

食品保鲜黑科技 来源:中国农业大学

食品贮藏保鲜技术论文英文翻译版

SummaryPolyphenol oxidase (polyphenol oxidase,PPO) is a key enzyme caused Browning of Strawberry, strawberry Browning has been the factors affecting Strawberry fresh-keeping and processing of critical, the study on industrialization of deep processing of Strawberry polyphenol oxidase colour preservation during transport and storage are This paper mainly studies the optimum conditions of extraction and purification of polyphenol Sediment filter first with acetone powder extraction of polyphenols from strawberry yanghuamei, using single-factor test to determine the key factors, and came with orthogonal optimum extraction condition of polyphenols oxidase: pH is 8, solid to liquid ratio of 14, the temperature of 30 ° c, and extraction time of Factors influencing the test results of the primary and secondary order is pH> temperature > liquid > extraction Under these conditions the extracting of crude enzyme solution using fractional precipitation method for ammonium sulfate purification, found in the ammonium sulfate saturation as 50% per cent precipitation reactions, through the determination of enzyme activity, determining polyphenol oxidase in 80% precipitation By testing the enzyme was purified by 5 times times and final yield of 67%Key words: extraction and purification of polyphenol oxidase

食品贮藏保鲜技术论文英文摘要

摘要:目:解同储存条件油炸食品间情况其影响素析油脂酸败随机选取超市批发市场新市接近其便面酸氧化值价格耐久性;群抽随机抽取摊点圣圣脆别放置室温冰箱0四八别酸氧化值价格结:近便面氧化值保质期比刚市超市销售便面氧化值比批发市场高;圣-圣-克斯普并储存间氧化值比存储间提高短;存储圣脆氧化物冰箱比些室温储存结论低贮存间贮存条件影响失油炸食品脂肪酸

近年来,国内外果蔬贮藏保鲜技术发展很快,其中采用降温、降氧、控制二氧化碳及乙烯含量的气凋贮藏保鲜技术应用较为广泛。现将果蔬贮藏保鲜技术的原理、方法及发展前景做一介绍。

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