微波条件下二苯甲酮与1-羟基环己基苯基甲酮从微波纸向Tenax中的迁移规律

采用高效液相色谱法(HPLC)对不同微波100、250、440、600W条件下二苯甲酮(BP)和1-羟基环己基苯基甲酮(HCH)从微波纸向脂肪类模拟物Tenax中的迁移规律进行研究。在此基础上,将微波加热的迁移结果与常用恒温迁移实验方法的结果进行比较。结果表明:BP在微波250W和440W时的最大迁移率几乎相同,而HCH在微波440W和600W时最大迁移率几乎相同,且微波条件下的最大迁移率小于常用恒温条件下的最大迁移率。除了功率的作用,温度和所做功对BP和HCH的迁移也有影响,且相比常用恒温加热的迁移实验,微波加热能加快BP和HCH在脂肪类物质中迁移行为的发生,但最大迁移率降低。     

微波条件下纸包装油墨中增塑剂向食品（模拟物）的迁移

研究纸张印刷油墨中4 种增塑剂（3 种邻苯二甲酸酯类增塑剂和近年流行的环保增塑剂乙酰基柠檬酸三丁酯）向食品模拟物Tenax和奶粉的迁移,考察其在110、250、440、600、900 W微波功率下的迁移行为,探讨迁移影响因素,并与常规条件下的迁移行为做比较。结果显示在一定条件下微波功率越高,迁移量越大;且迁移行为受增塑剂的分子质量、极性等性质的影响;常规条件下的迁移影响因素也适用于微波条件。     

辣椒粉微波杀菌工艺的研究

辣椒粉可采用高温杀菌、辐照杀菌和微波杀菌等多种杀菌方式进行灭菌.本实验采用微波杀菌,在杀菌时间、微波炉功率、物料覆盖厚度不同条件下,分别以其中的一个条件为变量其他条件保持不变做单因素实验,以确定一个条件时辣椒粉杀菌的影响,找出最佳工艺条件.然后在单因素实验的基础上对辣椒粉进行正交实验,得到最佳实验工艺条件为:杀菌时间120 s、微波炉功率510 W、物料覆盖厚度15 mm.与常规加热处理相比,辣椒粉采用微波杀菌不仅能达到较好的杀菌效果,而且品质保持良好.     

微波条件下陶瓷食品接触材料中有害重金属迁移行为的研究

目的 研究微波条件下陶瓷食品接触材料中有害重金属的迁移行为。方法 向陶瓷餐具中装入乙酸溶液, 进行常规处理和微波加热处理, 最后用火焰原子吸收分光光度计检测, 研究微波功率、加热时间和迁移液pH值对陶瓷餐具中铅、镉向乙酸溶液迁移的影响, 并将该方式与常规方式作对比。结果 铅、镉的迁移量随微波功率和加热时间的增加而增大, 并基本在加热15 min后达到迁移平衡; 微波功率不但影响铅、镉的迁移速度, 还影响其达到迁移平衡时的浓度; 铅、镉的迁移量随迁移液pH值的降低而增大。结论 通过短时间的微波加热, 即可使铅、镉的迁移量达到甚至显著超出(22?2)℃温度下浸泡24 h?20 min的迁移量。     

微波条件下聚烯烃抗氧剂向食用油迁移的扩散系数研究

实验研究不同微波加热功率条件下PE膜内三种不同分子量不同分子结构的抗氧化剂(BHT、Irganox 1076和Irgafos 168)向6 种食用油的迁移,计算相应的扩散系数并给出其与微波加热功率的关系图。鉴于微波加热条件下迁移的特殊性,提出构建新的扩散系数预测模型的设想。     

微波加热对速冻油条品质的影响

为了得到速冻油条方便、快捷的加热方式,研究微波加热条件(微波功率、加热时间和加热质量)对速冻油条温度、水分含量、质构性质等品质特性的影响。依据感官评价结果,得到最佳微波加热条件。研究结果表明:240 W微波功率加热速冻油条160 s,水分损失少,食用口感好,感官品质高,是速冻油条的最佳加热条件。若要节约时间或节能省电,更适宜采用400 W加热90 s或者640 W加热60 s的加热条件。     

微波条件对食品接触材料化学迁移的影响

模拟微波炉使用条件,考察了多种不同材质的食品接触材料在4种食品模拟物(水、4%乙酸、65%乙醇、正己烷)中总迁移量大小和迁移规律。结果表明,样品在一种或多种食品模拟物中都有一定程度的迁移,且在4%乙酸中迁移相对较大。通过研究微波条件对食品接触材料迁移的影响,发现随着微波加热功率的增大和加热时间的延长,样品向食品模拟物中的迁移量增大。随着样品循环使用次数的增加,迁移量逐渐减少。     

黑莓微波真空干燥传热特性

对黑莓进行微波真空干燥,研究不同微波功率和真空度对黑莓干燥过程中温度的影响,观察样品整个温度场的分布规律。采用数值模拟的方法,建立电磁与传热耦合模型,经过2min的微波真空加热,得出不同微波功率、不同真空度下黑莓的仿真温度场分布图。选取微波功率为400 W,真空度为-60kPa的条件进行试验,对数值模拟的结果进行分析和评定。仿真的意义在于规避加热区域的冷点位置,同时选取合适的微波功率和真空度以降低热点区域的温度差异性,保证实际加热时同一批次的样品加热效果基本一致。结果表明:黑莓在微波功率为400 W,真空度为-80kPa的条件下加热2min后,热点的温度维持在60℃左右,温度差异性为0.27,在样品热点区域加热温度高度一致性的前提下,保证了合适的加热温度,满足黑莓的干燥要求。     

微波复热时间和微波功率对预油炸牛肉串品质的影响

研究了微波加热时间(30、40、60、90、120s)和微波功率(350、490、700W)对预油炸牛肉串出品率、剪切力、色差和感官评价的影响.结果表明,在不同微波复热条件下,牛肉串的出品率、剪切力、色差变化和总体可接受性存在明显差异(p＜0.05).在同一微波功率条件下,随着微波加热时间的延长,肉串的出品率逐渐下降,亮度L*值降低,红色度a*值升高;除微波加热30s外,随着微波加热时间的延长,肉串的剪切力值增加,嫩度下降.牛肉串在700W加热40s、490W加热40s和60s时,不仅明显提高了肉串的出品率,而且改善了牛肉串的色泽,并使肉串保持较低的剪切力值.     

不同功率微波加热对提取液中叶绿素含量的影响

研究以叶绿素丙酮提取液为研究对象,分析不同功率微波加热下对提取液中叶绿素含量和颜色参数的影响。结果表明,微波加热下提取叶绿素可显著减少因加热导致的叶绿素a的降解,400W功率下叶绿素a的降解幅度最小。叶绿素b的降解受微波功率的影响,微波功率越高,开始降解的时间越早,后期则含量下降幅度相似。叶绿素b的降解程度显著影响提取液颜色由绿转黄的程度变化(P<0.05),但提取液绿色值与叶绿素a、b含量均不相关(P<0.05)。     

食品加工新技术——微波灭菌

<正> 微波是辐射的电磁波,其波长约在10~(-3)～10~(-1)米数量级,频率为300兆赫～300秭赫,与电离辐射不同的是,微波用于食品加热已有一段时间,但微波用于食品灭菌处理则时间较短。 微波灭菌机理 微波与生物体的相互作用是一个极为复杂的过程。当生物体受到微波辐射后会吸收微波能,从而产生热效应,加上生物体在微波场中发生生理反应和变化,也会影响微生物的生存率。微波辐照细菌致死的原因是微波热效应和非热力生物效应共同作用的结果,两种效应相互依存、相互加强。     

Microwave Bumping: Quantifying Explosions in Foods During Microwave Heating

An apparatus was developed to quantify the degree of bumping due to the explosion of food particulates during microwave heating. The apparatus consisted of a sound recording device, a digital storage oscilloscope, and an electric filter. Degree of bumping for a product was defined by integration of the magnitude of an explosion over time of bumping. The sound spectrum of explosion was analyzed by Fast Fourier Transform (FFT) analysis. Frequency of bumping was usually in the range 1.6 kHz to 8 kHz. The character of microwave bumping varied according to localized microwave superheating effects, product formulations, and prior heat treatment of the food.     

Microwave Blanching of Vegetables

ABSTRACT: Three vegetables, spinach, carrot, and bell peppers were blanched conventionally in water and using pulsed microwave at 95 ± 2 C. The effect of various parameters like mass of the product, mobility of the product in the microwave field, and physical geometry on the temperature attained was evaluated. The study also included the kinetics of peroxidase inactivation, temperature, and power distribution during microwave blanching. The study highlights the potential application of microwave blanching in reducing the loss of valuable nutrients. The kinetics of peroxidase inactivation indicated that microwave blanching was comparable to water blanching with higher reaction rate in the case of water blanching. The temperature and absorbed power levels during microwave blanching was influenced by the vegetable itself, its quantity, shape, location in the oven, and the microwave power applied.     

Microwave digestion of proteins

 The time needed for a conventional acidic digestion of peptide bonds in proteins with 6 N HCl was reduced from 18–24 h to 2 h when microwaves were applied. The rate-determining step of the splitting of the peptide bonds depends on the amino acid composition of the proteins. Myoglobin, lysozyme and bovine serum albumin were tested as pure model proteins. The amino acid contents determined after ion-exchange HPLC and postcolumn derivatisation with ninhydrin correlated well with values obtained on the basis of known amino acid sequences. Tryptophan, methionine as well as cysteine/cystine were partly or completely destroyed under the hydrolysis conditions applied. Almost 95% of the thermolabile amino acids (based on theoretical values) could be recovered. The conditions were further applied for the hydrolysis of food proteins like casein, commercially available whey proteins as well as pea proteins, and a comparison with the results of the conventional hydrolysis (24 h) was made. Received: 26 February 1998 / Revised version: 20 March 1998     

Microwave digestion of proteins

 The time needed for a conventional acidic digestion of peptide bonds in proteins with 6 N HCl was reduced from 18–24 h to 2 h when microwaves were applied. The rate-determining step of the splitting of the peptide bonds depends on the amino acid composition of the proteins. Myoglobin, lysozyme and bovine serum albumin were tested as pure model proteins. The amino acid contents determined after ion-exchange HPLC and postcolumn derivatisation with ninhydrin correlated well with values obtained on the basis of known amino acid sequences. Tryptophan, methionine as well as cysteine/cystine were partly or completely destroyed under the hydrolysis conditions applied. Almost 95% of the thermolabile amino acids (based on theoretical values) could be recovered. The conditions were further applied for the hydrolysis of food proteins like casein, commercially available whey proteins as well as pea proteins, and a comparison with the results of the conventional hydrolysis (24 h) was made. Received: 26 February 1998 / Revised version: 20 March 1998     

Microwave phase control heating

Summary Food processors are increasingly looking towards new microwave-based technologies to deliver competitive advantage in the market place, reduce operational costs, allow greater product innovation and increase flexibility without the need for large capital investments. The technical barriers to the widespread exploitation of microwave heating, and opportunities for microwave heating in food processing, are discussed in the context of the need to understand the microwave field/material/process interaction. It is shown how a new application of interference techniques, called phase control microwave heating, may offer opportunities for enhanced heat transfer in food processing, especially for direct control of the spatial power deposition within a foodstuff. Simulations of phase control heating using a 3D FETD microwave model, validation of experimental findings and examples in other applications are presented.     

微波技术应用(英文)

As a new development technique microwave technology has applied widely in areas of food processing.This article summarized the principles and characteristics of microwave technology and applications of microwave processing technology in meat products, cereals, fruits and vegetables processing.Some problems existed in microwave applications were analyzed.The development trend of microwave processing technology in food industry was put forward.     

棉织物微波染色研究

研究了棉织物的微波活性染色与固色,并与常规染色工艺进行了比较.试验结果表明:经微波染色或固色的织物,其上染率和色牢度普遍达到或高于常规水浴加热法染色;微波加热可以大大缩短染色时间,节能效果明显.     

Microwave and Radio Frequency Processing

SCOPE OF DELIVERABLES: The use of microwave and radio frequencies to heat food for commercial pasteurization and sterilization in order to enhance microbial safety is discussed here. Although not under FDA regulations, use of microwave technology to enhance microbial food safety in the home is also discussed briefly. Mechanisms of heating food and destroying pathogens, and the validation of industrial processes are also discussed, followed by conjecture on handling deviations during industrial processing. This document summarizes information obtained through published literature and personal contacts with industry, academia, and government. Although radio frequency is covered whenever possible, very little information on radio frequency heating for commercial pasteurization or sterilization of food is available in the published literature and no commercial facility for this purpose could be located. The microbial inactivation mechanisms of radio frequency heating are also quite similar to those of microwave heating. Thus, this document refers mostly to microwave processing with the implicit assumption that the principles are generally applicable to radio frequency. Specific information on radio frequency is included whenever available.