基于温度控制的猕猴桃片微波真空干燥特性研究

目的：研究温度控制下猕猴桃片微波真空干燥特性,并确定其最佳数学干燥模型。方法：以猕猴桃片为原料,利用自制的温度自适应微波真空干燥机干燥猕猴桃片,研究不同控制温度、真空度和微波功率密度对其干燥特性和水分有效扩散系数的影响,利用SPSS 19.0软件将试验数据与6个常用的薄层干燥模型进行非线性拟合,以确定系数R²,均方根误差R_MSE及卡方χ²作为评价指标,筛选出最佳干燥模型。结果：温度控制条件下的猕猴桃片的微波真空干燥为降速干燥过程,无明显恒速阶段。在试验范围内,控制温度与真空度对猕猴桃片的干燥特性影响显著,控制温度越高、真空度越大,物料的干燥速率越大;根据费克第二定律计算出猕猴桃于温度控制下微波真空干燥过程中的水分有效扩散系数,且随着控制温度与真空度的增大而增大,其最大值为6.814 97×10^-6 m²/s,平均活化能为70.77 kJ/mol。所选用的6个模型中,Two-term exponential模型具有最大的确定系数R²（0.999 9）,最低的R_MSE（0.002 02）和最小的χ²（0.000 30）,是猕猴桃片温度控制下微波真空干燥的最佳模型。结论：控制温度、真空度对猕猴桃片微波真空干燥特性、干燥速率和水分有效扩散系数具有显著影响。在试验范围内,Two-term exponential模型的拟合度最高,可有效描述猕猴桃片温度自适应下微波真空干燥过程中的水分随时间的变化规律。     

利用低场核磁共振技术分析月柿果片微波间歇干燥过程中的内部水分变化

为探究广西月柿果片在微波间歇干燥过程中的水分变化规律和干燥效果,应用低场核磁共振技术,测定在不同的微波功率密度下果片干燥过程中的横向弛豫时间T₂反演谱,进而分析其内部的水分赋存状态及迁移规律。结果表明:新鲜月柿果片中主要存在三种状态的水,即自由水、不易流动水、结合水;月柿果片微波间歇干燥过程包括前期加速、中期恒速和后期降速阶段。当微波功率密度为3.1、2.7、2.3 W/g时,随着微波功率密度的增大,失水速度逐渐加快,干燥至终点所需的时间分别为 210、240、300 min;随干燥时间的延长,T₂弛豫时间均向左迁移,峰总面积减小。根据MRI图像可知柿子的失水方向是由表面向内部逐步进行,最先消失的是最外侧的部分,中心部位直到干燥后期才逐渐减少直至消失。     

微波干燥工艺对月柿果片色泽质构及感官品质的影响

采用微波干燥技术对月柿果片进行干燥,考察微波功率、切片厚度、装载量对月柿片色泽、硬度、咀嚼性、复水比、感官评分等品质特性的影响。结果表明：随着微波功率增加,月柿果片的L*值、b*值显著减小（p<0.05）,而a*值、色差值（ΔE）、硬度、咀嚼性的趋势相反;复水能力与感官评分出现先升高后下降的变化,均在280 W时达到峰值。当切片厚度不断提升,月柿果片由焦黑色逐渐转变为亮黄色,柿片的硬度、咀嚼性显著提高（p<0.05）,复水能力不断减弱,感官评分升高,但当厚度超过2.00 cm,干制品呈红褐色,L*值、b*值下降,柿片偏硬,难以咀嚼,易粘牙,感官评分降低。随着装载量的提高,干燥样品色泽越接近鲜柿,硬度变小、韧性下降,而复水比、感官评分呈现先增加后减少的趋势。综合而言,在微波功率280 W、切片厚度2.00 cm、装载量1.60 kg/m2的条件下,柿片L*值48.39,a*值12.89,b*值33.61,ΔE值24.94,硬度值2316.23 g,咀嚼性1106.97 g,复水比达1.77,感官评分为87.80分,此时产品色泽亮丽,软硬适中,富有嚼劲,复水性好,具有月柿风味浓郁和感官品质优良的优点。     

厚度控制对怀山药远红外干燥过程中水分迁移的影响

采用远红外干燥设备对鲜怀山药片进行脱水处理,应用低场核磁共振波谱分析和成像分析技术,测定怀山药片干燥过程中的水分状态,综合干燥曲线、干燥速率规律,分析不同切片厚度（4,8,12 mm）的怀山药在干燥过程中的水分扩散特性,并建立薄层干燥模型。结果表明：干燥过程中干燥速率呈现短暂的快速上升后逐渐下降的趋势,4 mm的怀山药达到干燥条件所需时间较8,12 mm的分别短36.33%,53.33%;3种状态水分T₂峰面积减小且峰向左移动,干燥过程中自由水耗尽,干燥终点怀山药内部水分主要为结合水（87%）与少量弱结合水（13%）;怀山药内部水分存在密度梯度,从高密度向低密度方向迁移,适当减小怀山药厚度可促进H⁺质子密度下降,提高干燥效率;Page模型拟合效果较好（R²＞0.9）,能很好地表征和预测怀山药远红外干燥过程。     

微波热烫和气调包装对中央厨房用胡萝卜理化特性及品质的影响

胡萝卜经去皮、切分等加工后容易受到氧气和微生物的作用而发生腐败变质,因此,需要合适的保鲜方法延缓其品质劣变。作者研究微波热烫和气调包装对鲜切胡萝卜贮藏品质的影响。对胡萝卜进行微波热烫和气调包装处理后,每隔5 d测定胡萝卜样品的硬度、β-胡萝卜素质量分数、水分质量分数、水分活度、水分状态、过氧化物酶活性、颜色和微生物数量等指标。微波热烫可以有效降低胡萝卜中的微生物数量,并降低其水分迁移率。相比之下,对照样品中自由水（T₂₄）的质量分数更为突出。360 W微波热烫300 s结合高氧气调包装（体积分数80% O₂、10% CO₂、10% N₂）降低了储藏期内胡萝卜中β-胡萝卜素的降解、硬度的损失和过氧化物酶的活性,且更好地控制了胡萝卜中水分活度和水分质量分数的增加。低功率微波热烫结合高氧气调包装是一种有效的保鲜方法,可用于改善胡萝卜的储藏品质。     

苹果片微波间歇干燥特性及模型拟合

利用微波在线检测装置将微波间歇干燥技术用于苹果片薄层干燥试验,研究了苹果片在700、600、450、250 W功率,切片厚度为3、5、7、9 mm,单次微波加热时间4、5、6、7 s下的干燥动力学特性。试验结果表明,苹果片微波间歇干燥过程属于降速干燥。微波功率、切片厚度、加热时间对干燥过程影响显著。水分有效扩散系数随着干燥功率的升高、切片厚度的增加、加热时间的延长而增加。通过模型拟合可知Weibull模型具有较高的预测精度,能很好地描述苹果片微波间歇干燥试验过程规律,利用逐步回归法,确定了Weibull模型参数α、β的表达式。模型的尺度参数α随功率增大、厚度减小、加热时间增加而减小,说明增大干燥功率、减小切片厚度、延长加热时间可以显著缩短干燥时间、提高干燥效率。功率、厚度和加热时间对形状参数β影响很小,说明干燥过程中物料状态变化较小。     

响应面优化微波辅助提取黑莓果渣黄酮及其生物活性研究

目的 以黑莓果渣为原料,采用微波辅助提取黑莓果渣中黄酮并研究其生物学活性。方法 通过单因素试验考察微波时间、微波功率、液料比和乙醇浓度这四个因素对黑莓果渣黄酮提取工艺的影响,并通过响应面设计优化黄酮的最佳提取条件,确定黄酮的最佳提取工艺条件。以清除铁还原力、2,2’-联氨-双-(3-乙基苯并噻唑啉-6-磺酸)二胺盐(ABTS)能力和超氧阴离子(O_^2-.)来评价抗氧化能力和胰脂肪酶抑制率来评价其降血脂能力。结果 结果表明：黑莓果渣黄酮最佳提取工艺条件为微波功率300 W,微波时间8 min,微波温度55 ℃,乙醇浓度60 %,料液比1：20(g：mL),在此条件下黑莓果渣黄酮最高提取率为15.45 mg/g。黑莓果渣黄酮具有较强的抗氧化活性和降血脂能力,铁还原力、清除ABTS自由基能力、清除O_^2-.能力及胰脂肪酶抑制率均表现出一定的质量浓度依赖性；黑莓果渣黄酮铁还原力、清除ABTS自由基能力、清除O2-.能力及胰脂肪酶抑制率的半数有效质量浓度(EC50)分别为0.472 g/L、0.620 g/L、0.545 g/L和10.674 g/L。S结论 黑莓果渣黄酮可以作为一种天然的食源性抗氧化和降血脂添加剂。     

利用低场核磁共振技术研究调味山药片真空微波干燥过程中水分的变化规律

为研究调味山药片真空微波干燥过程中内部水分含量、分布及状态变化情况,采用低场核磁共振技术,测定不同微波功率下微波真空干燥过程中的横向弛豫时间T2反演谱,进而分析调味山药片内部的水分状态及其变化规律。结果表明：微波功率越高,自由水和不易流动水被除去所需的时间越短,其中对自由水作用尤为明显,但过高的微波功率会导致物料出现焦化现象;调味山药片干基含水率与核磁共振总峰面积之间呈线性关系,可以预测调味山药片真空微波干燥达到干燥终点所需的时间。核磁共振图像显示调味山药片干燥过程中水分含量的增加和减少均是由外而内,干燥结束时,剩余水主要存在于调味山药内层。水分含量的变化对调味山药片干燥后的品质有显著影响,低场核磁共振及成像技术为调味山药片干燥过程中水分的变化提供了直观的参考依据,本研究可以为调味山药片的真空微波脆化工艺设计、优化干燥参数、控制干燥过程及提高产品质量提供参考。     

芒果切片热风干燥特性及模型

目的：为对芒果热风干燥过程进行预测与控制。方法：以新鲜金煌芒为试验材料,研究热风温度（60,65,70 ℃）和芒果切片厚度（0.8,1.0,1.2 cm）对芒果热风干燥曲线、干燥特性曲线、水分有效扩散系数等的影响,并选取常用的适用于果蔬的6种干燥模型进行拟合、分析及验证,选出最适合芒果热风干燥的模型。结果：随温度的升高,切片厚度的减小,加快了芒果片的干燥速率,所需的干燥时间越短。水分有效扩散系数随温度和厚度的增大而增大,为1.401 39×10^-10～3.655 46×10^-10 m²/s。Logarithmic模型的R²最大、X²和RMSE最小,分别为0.998 87,0.000 124 779,0.001 37。结论：Logarithmic模型预测值与试验值验证基本吻合,可以较好反映芒果片在干燥过程中水分含量的变化规律。     

聚乙烯醇—鱼明胶—龙葵花青素复合膜的制备、结构表征及性能分析

目的：筛选出结构与性能最优的聚乙烯醇—鱼明胶—龙葵花青素（PVA/FG-SNA）复合包装膜。方法：通过正交试验优化PVA-FG膜的制备工艺,采用厚度、水分含量、水蒸气透过率（WVP）、拉伸强度（TS）、断裂伸长率（EB）、傅立叶红外光谱分析（FTIR）、X衍射分析（XRD）、扫描电镜分析（SEM）、热重分析（TG）探究不同质量分数SNA对PVA-FG膜性能和微观结构的影响,并监测PVA/FG-SNA复合膜的pH颜色响应和NH₃灵敏度。结果：当PVA-FG复配质量比为60∶40、加热温度为95 ℃、加热时间为1.5 h时,PVA-FG膜的水溶性为（36.03±2.63）%,WVP为2.91×10^-4 g·mm/（m²·h·Pa）;随着SNA质量分数的增加,PVA-FG膜的厚度、水分含量、WVP和EB随之增加。当SNA质量分数为0.2%时,复合膜的厚度为（0.07±0.01） mm,水分含量为（11.09±0.25）%,WVP为5.45×10^-4 g·mm/（m²·h·Pa）,TS为（21.12±1.07） MPa,EB为（373.77±8.59）%,且复合膜的各组分之间相容性较好。此外,PVA/FG-0.2% SNA膜在NH₃气氛条件下的颜色响应良好,可作为pH指示膜。结论：PVA-FG复合基膜的疏水性能和机械性能与SNA质量分数呈负相关,SNA可显著增强膜的pH和NH₃敏感性。     

微波爆裂玉米花浅谈

本文主要对近年市场上新出现的一种休闲食品——微波爆裂玉米花进行综述,并对制作微波爆裂玉米花的所需的原料、包装及影响其品质的因素进行了讨索。     

Drying of carrots in microwave and halogen lamp–microwave combination ovens

Carrot slices were dried by using microwave, halogen lamp–microwave combination and hot-air drying. Microwave and halogen lamp–microwave combination drying were applied after carrots were dried to 0.47 kg moisture/kg dry solid by hot-air drying. Drying time, rehydration capacity and colour of the carrots dried by different methods were compared. The increase in microwave oven power level decreased the drying time. Microwave drying at the highest power and halogen lamp–microwave combination drying reduced the drying time to an extend of 98% in comparison to conventional hot-air drying and a high-quality dried product was obtained. Moreover, in the case of halogen lamp–microwave combination drying, moisture level was reduced to a level, which is lower than the one achieved by other methods. Less colour change occurred when microwave and halogen lamp–microwave combination drying were applied. Carrots dried in microwave and halogen lamp–microwave combination oven had lower L*, higher a* and b* values and had higher rehydration capacity as compared to hot-air drying.     

微波萃取技术

对微波萃取技术的研究近况作了总结 ,着重说明了微波萃取技术的原理、优点、设备影响因素及其应用     

微波蛋糕的原料应用

Along with the advancement of the microwave oven manufacturing technique and the constant descend of its price, microwave oven equipment is gradually becoming the familiar application in family, the manufacture and consumption of lots of food use the technique of microwave processing, so the research on microwave recuperating food is one of the hottest researching subjects.     

Role of ceramic composites and microwave pulsing on efficient microwave processing of pork meat samples

A detailed theoretical analysis has been carried out to study efficient heating of one-dimensional pork meat (PLR and WP) slabs via an alumina–meat–ceramic–meatalumina composite corresponding to one side and both side microwave incidence. The ceramic (Al₂O₃ or SiC) layer is composited to examine processing rate and thermal runaway. Detailed analysis has been carried out for PLR and a few test cases are shown for WP. The role of an intermediate ceramic layer is examined for one side and both side microwave incidence cases. In general, the processing time decreases with the thickness of the intermediate ceramic layer for samples with thickness (Ls) ≤ 1 cm in the presence of one side incidence. On the other hand, the processing time is found to increase with the thickness of an intermediate alumina layer for both side incidence and a similar trend is also observed for larger sample thicknesses with one side incidence. It is found that the degree of the thermal runaway is reduced with the intermediate ceramic layer for samples with L_s ≤ 1 cm whereas the thermal runaway is enhanced with the inclusion of the intermediate ceramic layer for larger sample thicknesses. Further, the role of pulsing has been demonstrated for L_s = 1 cm. It is found that processing time with one side incidence is smaller than that with both side incidence in the absence of pulsing, but the trend is reversed in the presence of pulsing. Thus pulsed microwave heating in the presence of both side distributed incidence with an intermediate alumina layer is found to be an optimal heating strategy for processing meat samples.     

食品工业中的微波杀菌新技术

<正> 微波(microwave)是一种频率为300MHz～300GHz的高频电磁波,目前在冶金、化工、农业、医疗、轻工业等领域已被广泛采用;在食品工业上,则可用以烘烤食品。 微波杀菌技术是近年新兴的一项辐射杀菌技术。它不同于X-射线和γ-射线,是一种非电离辐射。与传统的加热方法相比,微波具有加热时间短、加热均匀、食品营养成分和风味物质破坏或损失少等特点;与化学药剂杀菌技术相比,微波杀菌因不会残留化学物质,其     

Characterization of microwave vacuum-dried durian chips

Durian CV. Monthong was subjected to microwave vacuum drying (at 13.33 kPa) to produce durian chips. Various levels of microwave power (3.88 W g⁻¹, 5.49 W g⁻¹ and 7.23 W g⁻¹) were used. Prior to the microwave vacuum drying, the sliced durian was either chilled at 4 °C or frozen at −18 °C. Both pretreatments yielded non-significant difference in dissipation factor (p > 0.05). Among several thin layer models, the Page model was found to be the best for explaining the drying characteristics of durian chips. An increase in the microwave power intensity produced a clear increase in the drying rate and did not affect lightness and yellowness of the durian chips (p > 0.05). The structure and hardness of the dried durian chips were comparable to that of conventionally fried durian chips. In addition, microwave vacuum drying reduced the fat content of the durian chips by at least 90%, compared with conventionally deep fried durian chips.     

微波辅助浸提鱼鳞卵磷脂的工艺研究

通过单因素试验,研究了乙醇体积分数、乙醇用量、提取时间、微波功率对鱼鳞卵磷脂提取量的影响规律,采用正交试验,得出了鱼鳞卵磷脂提取工艺的最佳参数组合为:乙醇体积分数95%、乙醇用量50mL/g、提取时间4min、功率240W。在此条件下每克鱼鳞中可提取卵磷脂23.87mg。     

Far-infrared and microwave drying of peach

Little detailed information is available for the far-infrared and microwave drying characteristics on peach and far-infrared combined with microwave drying on other food products. Experiments were conducted to study microwave and far-infrared dehydration characteristics and two-stage drying process involving far-infrared following microwave drying on peach. As microwave drying power and infrared drying power increased, dehydration rate of peach increased and whole drying energy consumption decreased. Peach experienced two falling rate periods when dried with microwave drying or far-infrared drying, and the first falling rate period under moisture content of peach more than 1.7 (dry basic, d. b.), the second falling rate period under less than moisture content 1.7 (d. b.). The same water loss will consume more energy and the steeper curve of energy versus moisture content were obtained when the moisture content is less than 1.7 (d. b.). However, differed from microwave drying, an accelerating dehydration rate period existed in the initial period of far-infrared drying. The effects of infrared drying power, microwave drying power and exchanging moisture content at former far-infrared drying converting into latter microwave drying (three factors) on energy consumption rate and sensory quality (two indices) are significant. The interaction effect of infrared drying power and exchanging moisture content on two indices is significant. The effects of second-order of microwave drying power and of interaction between infrared drying power and microwave drying power on energy consumption rate were not significant. The effects of second-order of exchanging moisture content and of interaction between exchanging moisture content and microwave drying power on sensory quality were not significant.     

微波干燥粮食的研究

介绍了微波干燥原理和特性以及加热系统,详细分析了微波对粮食干燥的作用机理,展望了其运用前景,以期加速微波技术在粮食干燥工程中的运用推广.