胡萝卜的缓苏作用及其在振动流化床中的间断干燥

对胡萝卜片（或块）在通气式振动流化床中干燥时各种参数对于干燥时间的影响作了初步的定量研究。绘制了各种参数对胡萝卜干燥时间的关系曲线，通过绘制通用干燥曲线得到时间、干燥速度及湿含量的影响关联式。并指出，对胡萝卜等蔬果物料采用变温干燥及间断干燥，对节能和提高质量均有重要意义。     

微波真空干燥工艺参数对猕猴桃切片品质的影响

微波真空干燥技术是在真空条件下利用微波能对物料进行干燥加工的一项新技术,本实验以猕猴桃切片为研究对象,以干制品复水率、维生素C含量以及干燥时间为指标,在单因素试验的基础上,通过3因素3水平的二次回归正交试验,研究了微波功率、物料厚度、干燥室压力对猕猴桃切片干燥特性的影响。结果表明：在微波功率为800W、切片厚度为4mm、干燥室压力为0．04MPa的条件下,微波真空干燥猕猴桃切片的干制品质量最好,确定了猕猴桃切片微波真空干燥较优工艺参数条件。     

干燥方式对红枣动力学及挥发性成分的影响

采用热风干燥、真空冷冻干燥和微波真空干燥对红枣进行干燥处理，结合顶空固相微萃取-气相色谱-质谱（headspace solid-phase microextraction-gas chromatography-mass spectrometry，HS-SPME-GC-MS）和电子鼻对枣片挥发性成分进行了分析，并对比了3种干燥方式对红枣色泽、动力学和挥发性成分的影响。结果表明，热风干燥和微波真空干燥对枣片色泽影响较大，真空冷冻干燥能够更好的保持原始色泽；对动力学方程进行拟合，发现Page 模型为预测红枣3种干燥方式干燥特性最适合的数学模型；干燥对枣片挥发性成分种类及相对含量差异显著，其中干燥前后相同的挥发性成分有19种。挥发性物质主要有酸类、酯类、醇类、醛类、酮类、烃类、杂环类和其他化合物，干燥过后枣片中酸类和烷烃类挥发性成分相对含量显著增加，醛类和杂环类物质显著降低。电子鼻结果表明干燥后枣片香气特征与新鲜红枣有较大的区别，热风干燥和微波真空干燥香味特征较为接近，微波真空干燥枣片的焦甜香特征更为明显。相较于热风干燥和真空冷冻干燥，微波真空干燥效率较高、能耗较低、周期较短，更适于制备干燥枣片。     

菠萝蜜果肉干燥特性试验研究

用微波真空干燥设备对菠萝蜜果肉进行干燥试验,选择不同功率、时间对干燥规律进行研究。根据干燥曲线,采用多元回归分析,建立了菠萝蜜果肉干燥的数学模型;通过正交试验得出在多因素条件下,功率对菠萝蜜干燥生产率的影响最为显著,其它依次为投物量,时间。     

微波真空干燥高粘度的灵芝浓缩液

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。     

微波真空组合干燥果蔬的研究

本文论述了微波真空组合干燥的基本原理及干燥特点,剖析了国内外微波真空组合干燥果蔬的研究进展情况,探讨了影响微波真空干燥果蔬品质的主要因素及应用前景。     

微波真空组合干燥技术的研究

微波真空干燥是综合微波干燥和真空干燥各自优点的一项新技术,将微波干燥的快速高效性和真空干燥的低温高质相结合,在真空条件下利用微波对物料进行干燥处理,从而实现物料的快速低温干燥。着重阐述了微波真空组合干燥技术的机理、特点、干燥动力学以及影响微波真空干燥的重要因素,并对微波真空组合干燥的应用研究进行了介绍。     

微波干燥复肥初步研究

阐述了微波干燥复肥的可行性，进行了微波干燥复肥的实验，得到微波干燥尿基复肥的失水曲线、温度曲线及养分曲线。同时作了60℃常规干燥的对比实验，表明微波干燥复肥能够达到有关标准，并远优于常规干燥。     

黄精微波真空-热风联合干燥工艺研究

以黄精含水率为指标,采用单因素和均匀实验方法,对黄精微波真空干燥工艺进行优化,考察联用的热风干燥温度和时间对黄精多糖含量及其抗氧化活性的影响。结果表明,微波真空-热风联合干燥的最优工艺条件为:微波功率2 k W、间歇比1.67(75/45),真空度0.085 MPa,微波真空干燥37 min,再在55℃的热风下干燥约77 min。在该条件下,黄精干制品多糖含量达61.7 mg/g,对O~(2-)的抑制率达24.1%。微波真空-热风联合干燥技术可以应用于黄精的干燥。     

黄精微波真空-热风联合干燥工艺研究

以黄精含水率为指标,采用单因素和均匀实验方法,对黄精微波真空干燥工艺进行优化,考察联用的热风干燥温度和时间对黄精多糖含量及其抗氧化活性的影响。结果表明,微波真空-热风联合干燥的最优工艺条件为:微波功率2 k W、间歇比1.67(75/45),真空度0.085 MPa,微波真空干燥37 min,再在55℃的热风下干燥约77 min。在该条件下,黄精干制品多糖含量达61.7 mg/g,对O^(2-)的抑制率达24.1%。微波真空-热风联合干燥技术可以应用于黄精的干燥。     

Effect of Microwave-Vacuum Drying on the Carotenoids Retention of Carrot Slices and Chlorophyll Retention of Chinese Chive Leaves

Microwave-vacuum drying, and combined microwave-vacuum with air or vacuum drying were investigated as potential methods for drying green and high-carotenoid vegetables of Chinese chive leaves and carrot slices. The samples were dried by microwave-vacuum until the moisture content reached about 20% (wet basis), and then by conventional air drying at the temperature of 45-50°C or conventional vacuum drying at the temperature of 55-60°C or by continued microwave-vacuum drying at lower power level to final moisture content about 6% (wet basis). The carotenoid retention of carrot slices and chlorophyll retention of Chinese chive leaves, dried by these methods, was evaluated and compared with those dried by freeze-drying and conventional hot-air drying. The comparison showed that the carotenoid retention of carrot slices and chlorophyll retention of chive leaves, dried by the current methods, was very close to or even as much as those dried by freeze-drying and much better than those dried by conventional hot-air. Blanching was not necessary when using microwave-vacuum drying or combined microwave-vacuum with conventional hot-air drying or vacuum drying, because the activity of enzymes which were responsible for the degradation of color was greatly reduced with extremely rapid decreasing of moisture, and because oxygen was absent in microwave-vacuum drying.     

Combined Microwave-Vacuum and Freeze Drying of Carrot and Apple Chips

A combination of microwave-vacuum (MWV) drying and freeze drying was investigated as potential means for drying carrot and apple chips. The sample was first dried by microwave-vacuum to dehydrate some amount of internal free water and then by freeze drying to a final moisture content of less than 7% (wet basis). Chemical properties (carotene and vitamin C retention) and physical properties (shrinkage, color, texture, and rehydration ratio) of carrot and apple slices dried by this method were evaluated and compared with those dried by freeze drying alone, MWV drying alone, and conventional hot air drying, respectively. The comparison showed that the carotene retention of carrot slices and the vitamin C retention of apple slices dried by the current method were close to those of freeze-dried carrot and apple slices and much better than those of conventional hot air–dried ones. The samples prepared by the current method exhibited very close rehydration capacity, color retention, and texture with those of the freeze-dried ones but with a little higher shrinkage. However, the samples still showed the attractive external appearance without marked warp.     

EFFECT OF MICROWAVE DRYING ON SOME QUALITY PROPERTIES OF DEHYDRATED PRODUCTS

The effect of microwave and microwave-vacuum drying on some quality properties such as density, porosity, color and viscoelastic behavior of dehydrated apple, banana, carrot and potato was investigated. It is concluded that microwave drying and moreover microwave-vacuum drying tends to increase the product porosity and to prevent the color damages during drying. Microwave drying seems to decrease the maximum stress and maximum strain of dehydrated products, while it increases their elasticity and decreases their viscous nature     

Internal Resistance to Water Mobility in Seafood during Warm Air Drying and Microwave-Vacuum Drying

We present a novel microwave-vacuum drying technique as an effective method for seafood. Microwave is irradiated just for the latent heat supply to keep the material at room temperature. We made several experiments using the scallop and examined the internal resistance for water transport based on the porous media model. The experimental and theoretical study indicates that the microwave-vacuum drying keeps the channel for water transportation and results in the high permeability at the wide range of moisture content. The drying time was significantly shortened as compared with the warm-air drying and the room-temperature drying results in good quality of dried seafood.     

Dehydration of Garlic Slices by Combined Microwave-Vacuum and Air Drying

Combination of microwave-vacuum drying and air drying was investigated as a potential mean for drying garlic slices. The sample was dried by microwave-vacuum until the moisture content reached 10% (wet basis), and then by conventional hot-air drying at the temperature of 45°C to final moisture content less than 5% (wet basis). Pungency, color, texture, and rehydration ratio of garlic slices dried by this method were evaluated and compared with those dried by freeze drying and conventional hot-air drying. The comparison showed that the quality of garlic slices dried by the current method was close to that of freeze dried garlic slices and much better than that of conventional hot-air dried ones. The lab microwave-vacuum dryer which the materials to be dried could be rotated in the cavity was developed by the authors.     

Dehydration of Garlic Slices by Combined Microwave-Vacuum and Air Drying

Abstract

Combination of microwave-vacuum drying and air drying was investigated as a potential mean for drying garlic slices. The sample was dried by microwave-vacuum until the moisture content reached 10% (wet basis), and then by conventional hot-air drying at the temperature of 45°C to final moisture content less than 5% (wet basis). Pungency, color, texture, and rehydration ratio of garlic slices dried by this method were evaluated and compared with those dried by freeze drying and conventional hot-air drying. The comparison showed that the quality of garlic slices dried by the current method was close to that of freeze dried garlic slices and much better than that of conventional hot-air dried ones. The lab microwave-vacuum dryer which the materials to be dried could be rotated in the cavity was developed by the authors.     

Drying Behavior of Carrots Dried in a Spout–Fluidized Bed Dryer

The effect of water blanching treatment and the inlet air temperature on drying kinetics as well as the quality attributes of carrot cubes dried in a spout–fluidized bed dryer at 60, 70, 80, and 90°C were analyzed. The material shrinkage and the rehydration potential were calculated to assess the changes in quality of dried carrots. It was found that the value of the air velocity during the drying of carrot cubes in a spout–fluidized bed dryer should be related to the moisture content of the carrot particles. A high value of air velocity at the beginning of the drying cycle and a lower value for the later stages were also required. The linear equation was correlated to the data of shrinkage of raw and blanched carrots. Blanching significantly influenced the coefficients in the shrinkage model derived for drying of carrot cubes in a spout–fluidized bed dryer, while drying temperature did not influence the shrinkage of carrot particles. The intensity of heat and mass transfer during spout–fluidized drying of carrot cubes was dependent on the drying temperature. A correlation was developed to calculate the values of effective moisture diffusivity of dried carrot cubes as a function of the moisture content and temperature of the material. It was observed that for any given time of rehydration, both the moisture content and the rehydration ratio calculated for samples dried at 60°C were higher than for samples dried at temperatures of 60, 70, 80, and 90°C.     

THE RELATIVE INFLUENCE OF DIELECTRIC AND OTHER DRYING TECHNIQUES ON THE PHYSICO - MECHANICAL PROPERTIES OF A PHARMACEUTICAL TABLET EXCIPIENT. PARTI: COMPACTION CHARACTERISTICS.

The relative Influence of nine techniques for drying wet granulated microcrystal-lline cellulose (MCC) on the subsequent compaction characteristics was studied In terms of the tensile strength and corrected work of failure of the tablets. Wet granulation resulted in a substantial decrease in compatibility. However, the drying technique used was found to affect the degree of loss in compatibility. In general, microwave-vacuum drying using the “high” process type resulted in the production of granules with the highest compatibility followed by freeze drying and fluidized bed drying. Granules dried under ambient conditions, and granules tray dried to “just dry” or “over dried” conditions resulted In tablets possessing approximately comparable compatibilites, with the poorest compaction characteristics being exhibited by vacuum dried granules, in addition It was found that use of a “low” drying process type during microwave- vacuum drying yielded granules with inferior compaction characteristics to those dried by the “high” process type. Radio frequency drying was found to yield granules which produced tablets having slightly inferior tensile strength to tray dried material, although the tablet work of failure values were comparable. The effect of drying technique on the subsequent compaction characteristics was not found to be directly related to the moisture content of the granules.     

Dehydration of Concentrated Ganoderma lucidum Extraction by Combined Microwave-Vacuum and Conventional Vacuum Drying

Combination of microwave-vacuum drying and conventional vacuum drying was investigated as a potential method for drying concentrated Ganoderma lucidum extraction. The Ganoderma lucidum was extracted by hot water (60-65°C) and then concentrated to moisture of about 70% (wet basis) in a rising-film evaporator. The concentrated sample was dried by microwave-vacuum until the moisture content reached 10% (wet basis), and then by conventional vacuum drying at the temperature of 55-60°C to final moisture content about 6% (wet basis). The retention of polysaccharide and triterpenes of Ganoderma lucidum dried by this method were evaluated and compared with those dried by freeze drying and conventional vacuum drying alone. The comparison showed that the quality of extraction dried by the current method was close to that of freeze-dried extraction and much better than that of conventional vacuum-dried ones.     

响应曲面法漂白紫胶微波-真空干燥工艺研究

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。