共查询到18条相似文献,搜索用时 140 毫秒
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热敏性、高粘度物料的干燥仍是现代干燥技术中的一个难题。灵芝水提后,由薄膜蒸发器浓缩至含水量70%左右,然后采用微波真空干燥(真空度3000Pa)至水分含量10%左右,改用传统的电热真空干燥(55~60℃)至含水量6%~7%。对干燥产品的主要生物活性成分——灵芝多糖和三萜酸进行了分析检测并与其它干燥方法进行了比较。结果表明:利用微波真空干燥的灵芝产品其灵芝多糖和三萜酸的保留率与冷冻干燥产品十分接近。而比传统真空干燥(60—65℃)的产品要高得多,此外采用微波真空干燥的干燥时间要短得多。 相似文献
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热风与真空冷冻联合干燥毛竹笋的试验研究 总被引:1,自引:0,他引:1
对毛竹笋进行了热风与真空冷冻联合干燥(AFD)的研究,应用热风与真空冷冻(AD FD)和真空冷冻与热风(FD AD)两种方式做不同转换点试验,将得到的产品分别与完全的热风干燥和冷冻干燥的产品比较其能量消耗和物化特性,并对它们的产品进行理化分析,确定了AFD联合干燥的方式和最佳转换点,得出了真空冷冻与热风(FD AD)联合干燥的产品接近完全真空冷冻干燥(FD)产品的结论,AFD联合干燥对于提高脱水笋干的质量、节省能量消耗是有效的。 相似文献
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为提高漂白紫胶产品质量及生产效率,采用微波-真空干燥漂白紫胶研究了不同压强、微波功率和干燥时间对漂白紫胶产品颜色指数和含水率的影响,用响应曲面法(RSM)设计试验并建立了该工艺条件的拟合方程。结果表明,拟合方程的拟合度较高,所建立的数学模型可以用于描述漂白紫胶的微波-真空干燥。漂白紫胶微波-真空干燥的最优条件:干燥压强为3.0 kPa,微波功率为795 W,干燥时间为30 min。在优化条件下进行了验证实验,得到了颜色指数为0.9、含水率为0.028 9kg水/kg干料的产品。 相似文献
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微波真空干燥技术现状 总被引:12,自引:0,他引:12
阐述了国内外微波真空于燥的研究现状,重点分析了脉冲微波真空干燥(间歇式微波干燥)的主要参数脉冲比、真空度、微波功率和能量效率。对微波真空于燥技术的发展提出了个人的看法。 相似文献
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胡萝卜微波真空干燥试验研究 总被引:3,自引:0,他引:3
以胡萝卜为原料,采用均匀设计对微波真空干燥的微波功率、干燥温度及料层厚度进行试验研究,分析各试验条件下的水分含量及胡萝卜素含量,得到了干燥曲线和胡萝卜素保有量曲线,得出了胡萝卜失水量、胡萝卜素含量与各因素之间的回归方程,可用于描述胡萝卜的微波真空干燥特性。 相似文献
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草莓冻干-真空微波联合干燥节能保质研究 总被引:2,自引:0,他引:2
微波真空干燥与冷冻干燥串联联合以减少草莓单纯冻干中的高能耗,同时使产品的质量得到很好的保持。从工艺角度出发,选取最佳水分转换点和后续微波真空干燥的最佳微波功率。另外,将冻干和真空微波干燥过程中的能耗分为有效能耗和无效能耗并进行计算,得出了FD11.5h+VMD的联合干燥能够得到外观最好的草莓,且无效能耗节约率为28.19%;而FD7h+VMD的联合干燥可使无效能耗节约50.28%,虽然没有最好的外观,但其产品仍然可被消费者接受。 相似文献
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The general objective of this work is to analyze energy input in a vacuum process with the incorporation of microwave heating. Thus, necessary criteria for designing an efficient freeze-drying operation are considered through the analysis of strategies based on the combination of different intensities of radiant and microwave heating. The other aim of this research topic is to study the kinetics of drying in relation to mass transfer parameters. Five freeze-drying strategies using both heating systems were used. Consequently, energy input could be related to diffusivity coefficients, temperature and pressure profiles during dehydration of the product and analyzed in comparison to a conventional freeze-drying process. 相似文献
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The general objective of this work is to analyze energy input in a vacuum process with the incorporation of microwave heating. Thus, necessary criteria for designing an efficient freeze-drying operation are considered through the analysis of strategies based on the combination of different intensities of raxiiant and microwave heating.The other aim of this research topic is to study the kinetics of drying in relation to mass transfer parameters.Five freeze-drying strategies using both heating systems were used. Consequently, energy input could be related to diffusivity coefficients, temperature and pressure profiles during dehydration of the product and analyzed in comparison to a conventional freeze-drying process. 相似文献
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Abstract The aim of this work is to model the drying kinetics of mushrooms under several operational conditions, to evaluate the effective diffusivity coefficient of moisture removing by a drying model and inverse calculus method in finite differences and to study the effect on the final quality of dehydrated mushrooms. Different ways of microwave vacuum drying were compared to freeze-drying. Results show that a decrement of the applied pressure produces a certain increase in the drying rate together with a lower moisture in the dehydrated product at the end. Temperature control inside the sample helps to ensure a better quality in the dehydrated product, than when controlled at the surface. Diffusivity coefficients show a correspondence with product temperature during drying. The microwave dried samples obtained with moderate power and temperature control of product shown an important degree of quality similar to that obtained by freeze-drying. 相似文献
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The aim of this study was the methodological use of experimental planning for the optimization of microwave vacuum drying of enzymes using α-amylase as a model. A factorial in star designwas used to optimize the microwave vacuum–drying process, and the variables were power output and vacuum pressure. The material dehydrated by this technique was analyzed with regard to its enzymatic activity, water activity, and moisture content. Response surface methodology was used to estimate the main effects of vacuum pressure and power on the enzymatic and water activities. The experimental in star design revealed that microwave vacuum drying is influenced mainly by power. The dehydrated product showed high enzymatic activity and low water activity. 相似文献
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A mathematical model of multicomponent vacuum desorption, which occurs in vacuum freeze-drying process, was developed. In freeze-drying porous biomaterials and pharmaceuticals are considered and the vacuum freeze-drying process, especially the moisture desorption in its final stage, is investigated. In this article, the drying with conductive heating and constant contact surface temperature was considered. Pressure drop is taken into account in the model formulation but was neglected in process simulation because of thin material layers undergoing freeze-drying. Model equations were solved by numerical method of lines. Moisture content and temperature distributions within the drying material were predicted from the model as a function of drying time. 相似文献
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Tzu-Ching Hsu 《Drying Technology》2013,31(5):566-572
It is well known that the drying of liquid-borne powders will create agglomerates and the problem of agglomeration is particularly acute in the nanoscale range. To eliminate/mitigate the agglomeration problem, in this study, a vacuum drying technique was used for drying the colloid solution with θ-Al2O3 ultrafine particles. For comparison purposes, other drying methods including oven drying, microwave drying, and freeze drying were also applied for drying of the same kind of colloid solution. The results indicate that the redispersibility, which is closely related to the degree of agglomeration, of the dried powders obtained from vacuum drying is better than that obtained from freeze drying. More surprisingly, results showed that the dried powders obtained from the vacuum drying assisted by microwave heating has the redispersibility close to 100%. 相似文献
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《Drying Technology》2013,31(8):1693-1709
Abstract A mathematical model of multicomponent vacuum desorption, which occurs in vacuum freeze-drying process, was developed. In freeze-drying porous biomaterials and pharmaceuticals are considered and the vacuum freeze-drying process, especially the moisture desorption in its final stage, is investigated. In this article, the drying with conductive heating and constant contact surface temperature was considered. Pressure drop is taken into account in the model formulation but was neglected in process simulation because of thin material layers undergoing freeze-drying. Model equations were solved by numerical method of lines. Moisture content and temperature distributions within the drying material were predicted from the model as a function of drying time. 相似文献