热风与真空冷冻联合干燥毛竹笋的试验研究

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。     

透明质酸钠冻干球化妆品生产工艺

对透明质酸钠冻干球的生产工艺进行研究，为规模化生产提供依据。以差示量热分析技术测定的共晶点和共熔点确定预冻和一次干燥的温度并设定冻干工艺曲线，以外观性状为指标对不同质量分数的透明质酸钠溶液进行筛选，并进行冻干工艺优化和验证。结果显示，质量分数1.5%的透明质酸钠溶液，-40℃预冻2 h,-5℃一次干燥12 h,40℃二次干燥4 h，冷冻干燥阶段均采用极限真空，如此制备的冻干球呈光滑球形，成形良好。选定的处方和冻干工艺可行，经验证明能够持续稳定地生产出外观质量符合要求的产品。     

黑加仑真空冷冻与微波真空联合干燥工艺研究

以黑加仑为原料,对其进行了真空冷冻与微波真空联合干燥工艺的研究。结果表明：先真空冷冻后微波真空干燥（FDMV）的组合方式是可行的;联合干燥合理工艺参数为：微波功率1．34kW。绝对压力11kPa,转换含水率为20％（wb）;通过试验验证,联合干燥生产的脱水黑加仑的感官品质和营养成分接近真空冷冻干燥,联合干燥方式对节省干燥时间和降低能耗是有效的。     

不同干燥方式制备白果粉的性能比较

天然产物白果会因干燥方式的不同,而使得干燥白果粉性能有所差别。本研究分别采用喷雾干燥(SP)与真空冷冻干燥(FD)对白果浆进行干燥处理。然后对两种干燥白果粉的性能(含水量、颗粒度、色泽、蛋白质质量分数)进行对比来比较各自的优越性。喷雾干燥采用参数:风量120 m³/h,进料浓度8%(质量分数),进气温度205℃,出气温度100℃,雾化器转速32000 r/min。真空冷冻干燥先在-40℃下预冻4h后,再在真空度300 Pa下-50℃低温干燥48 h。结果发现含水量SP相似文献   

麻疹减毒活疫苗冻干工艺的优化

目的优化麻疹减毒活疫苗的冻干工艺。方法以预冻过程(温度、时间)、升华干燥过程(温度、时间、真空控制值)、解析干燥过程(温度、时间、真空控制值)冻干参数为影响因素,应用L(827)正交试验设计冻干曲线,对8批麻疹减毒活疫苗半成品进行冻干,采用直观分析法的综合平均值R()iⅠ和极差R(i)j分析不同批次冻干制品的干损率、病毒滴度、热稳定性和残余水分,筛选最优因素水平组合,并对其进行适用性验证。结果优化的麻疹减毒活疫苗冻干工艺参数为:预冻:温度5～-25℃、时间0.5h,温度-25～-40℃采用大于1℃/min的冻结速率,温度-40℃、保持时间3h;升华干燥:温度-40～-20℃、时间1.5h、真空控制值0.16mbar,温度-20℃、保持时间8h、真空控制值0.16mbar,温度-20～30℃、时间5h、真空控制值0.16mbar;解析干燥:温度保持30℃、时间6h、真空控制值0.005mbar,以优化的麻疹减毒活疫苗冻干工艺冻干的制品成型良好,干损率平均为1.36%,稳定性好,残余水分在1.62%～1.67%之间。结论优化的麻疹减毒活疫苗冻干工艺适合麻疹疫苗大规模生产。     

微波干燥RDX新技术研究

以含水率10%的RDX为研究对象,采用特制的微波真空干燥仪干燥一定量的炸药,详细考察了各种因素对炸药干燥时间的影响.结果表明,在真空度为0.080 MPa,微波功率为1 400 W,物料层厚度为20 mm的条件下,923 g含水率为10%的RDX完全干燥时间为1 090 s,远小于常规干燥的7～8 h;当物料厚度为15～20 mm时干燥时间最佳.微波真空干燥对RDX的机械感度等性能无明显影响.     

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。     

富含果胶和黄酮类化合物的柑橘皮渣干燥工艺研究

为全组分高值化利用柑橘皮渣,研究了富含果胶和黄酮类化合物的柑橘皮渣干燥工艺。依次采用热风干燥和微波真空干燥脱除柑橘皮渣的水分,考察柑橘皮渣铺放厚度、干燥温度、干燥时间对皮渣含水率、果胶和总黄酮含量的影响。结果表明,热风干燥的最佳工艺条件为:皮渣铺放厚度2.0 cm,60℃干燥0.5 h;微波真空干燥的最佳工艺条件为:真空度-0.085 MPa,铺放厚度2.5 cm,50℃干燥2.0 h。在该条件下,柑橘皮渣含水率降至10%以下,果胶含量损失少于20%,总黄酮含量损失少于15%。该干燥工艺简单,可操作性好,能在脱除柑橘皮渣水分的同时最大限度保留了其中的果胶和黄酮类化合物,为全组分高值化利用柑橘皮渣提供有益的参考,为异地提取柑橘皮渣中果胶、黄酮等活性物质提供方便。     

富含果胶和黄酮类化合物的柑橘皮渣干燥工艺研究

为全组分高值化利用柑橘皮渣,研究了富含果胶和黄酮类化合物的柑橘皮渣干燥工艺。依次采用热风干燥和微波真空干燥脱除柑橘皮渣的水分,考察柑橘皮渣铺放厚度、干燥温度、干燥时间对皮渣含水率、果胶和总黄酮含量的影响。结果表明,热风干燥的最佳工艺条件为:皮渣铺放厚度2.0 cm,60℃干燥0.5 h;微波真空干燥的最佳工艺条件为:真空度-0.085 MPa,铺放厚度2.5 cm,50℃干燥2.0 h。在该条件下,柑橘皮渣含水率降至10%以下,果胶含量损失少于20%,总黄酮含量损失少于15%。该干燥工艺简单,可操作性好,能在脱除柑橘皮渣水分的同时最大限度保留了其中的果胶和黄酮类化合物,为全组分高值化利用柑橘皮渣提供有益的参考,为异地提取柑橘皮渣中果胶、黄酮等活性物质提供方便。     

Studies on Decreasing Energy Consumption for a Freeze-Drying Process of Apple Slices

The shape, color, flavor, and rehydration capacity of freeze-dried (FD) products are all better than other dried products. However, the energy consumption during FD is very high, which limits the application of this drying method for common materials. In this article, microwave vacuum drying (MWVD) was applied before or after FD to decrease the energy consumption during FD. Moreover, energy consumption was divided into two parts: valid and invalid energy consumption. Apple slices were used as an example to calculate the saving percentage of invalid energy consumption by comparing combination drying with FD. Apple slices freeze dried for 8.28 h first and then dried by MWVD have the best appearance, with a savings of 39.20% in invalid energy consumption. But apple slices freeze dried for 6 h first followed by MWVD have the highest savings of invalid energy consumption, 54.02%, while still maintaining an acceptable appearance.     

Effects of different drying methods on the physical characteristics and flavor of dried hawthorns (Crataegus spp.)

ABSTRACT

The objective of this study was to compare the physical characteristics and flavor of dried hawthorns obtained by freeze-drying (FD), microwave freeze-drying (MFD), atmospheric freeze-drying (AFD), and heat pump drying (HPD). The parameters including moisture content, product temperature, rehydration ratio, chroma, hue angle, yellowness index, total color difference, and energy consumption were investigated. The use of fuzzy reasoning for the sensory evaluation of hawthorn quality was also performed. As expected, AFD, FD, and MFD produced better accepted dried hawthorn products than did HPD. Nevertheless, FD consumed the highest energy and had a long drying time, but its product was the best; AFD had a similar energy cost as HPD, but its drying time was the longest; and MFD had a higher energy cost and longer drying time than HPD, but its product quality was similar to that of FD products. As a result, MFD and AFD had potential to replace FD to yield dried hawthorns with high product quality and relatively low cost.     

Freeze Drying of Apple Slices with and without Application of Microwaves

In this study, Fuji apple slices were dehydrated using freeze drying (FD) combined with microwave assisted with vacuum drying (VMD). The optimal parameter for the diversion point of moisture content from FD to VMD process was at the moisture level of 21%, and for VMD the optimal parameter for vacuum pressure was at 9.15 kPa and microwave power density was at a level of 3.18 w/g. The results show that the two-step technique can significantly reduce total FD time required by up to 40%, while the nutritional value of the dried apple chips remained unchanged compared to FD used alone.     

Studies on the Microwave Freeze Drying Technique and Sterilization Characteristics of Cabbage

The vacuum freeze-drying (FD) technique used in the food industry can yield a high-quality product, but it is very expensive and requires a long processing time. Besides, the quantity of microorganisms in FD products can often exceed the required standard. As a result, it will be important to develop a new freeze-drying technique. In this article, cabbage was used as a model material, and the microwave field was used as a heat source to supply sublimation heat so that the drying time was shortened greatly. The effect of the microwave sterilization during the drying process was evaluated. Effects of the pressure, thickness of material being dried, and the input microwave power on such indices as drying time and the microorganism number were studied. Compared with the method of ordinary freeze drying, microwave freeze drying (MFD) can greatly reduce the drying time and has a notable sterilization effect.     

Studies on the Microwave Freeze Drying Technique and Sterilization Characteristics of Cabbage

The vacuum freeze-drying (FD) technique used in the food industry can yield a high-quality product, but it is very expensive and requires a long processing time. Besides, the quantity of microorganisms in FD products can often exceed the required standard. As a result, it will be important to develop a new freeze-drying technique. In this article, cabbage was used as a model material, and the microwave field was used as a heat source to supply sublimation heat so that the drying time was shortened greatly. The effect of the microwave sterilization during the drying process was evaluated. Effects of the pressure, thickness of material being dried, and the input microwave power on such indices as drying time and the microorganism number were studied. Compared with the method of ordinary freeze drying, microwave freeze drying (MFD) can greatly reduce the drying time and has a notable sterilization effect.     

吸湿多孔介质冷冻干燥传质传热模型

本研究在作者提出的吸附—解吸平衡关系的基础上,建立了一个全新的考虑吸湿效应的多孔介质冷冻干燥数学模型。模型用有限差分法进行求解,并带有一个移动边界,以模拟介电材料辅助的微波冷冻干燥过程。介电材料选用碳化硅（SiC）,原料液为脱脂奶。模拟结果表明：介电材料能够有效强化微波冷冻干燥过程。在典型操作条件下,介电材料辅助的微波冷冻干燥所用的时间比普通微波冷冻干燥减少33.1%。当料液中固体含量较低或者固体产品的损耗因子较小时,介电材料对微波加热的效果不明显。基于冰饱和度、温度和水蒸气浓度的分布,本文分析了干燥过程中的传质传热机理,并对干燥速率控制因素进行了讨论。     

Study on a Combination Drying Technique of Sea Cucumber

To develop a highly efficient drying technique for sea cucumber, the effects of different drying methods on the drying procedure and product quality were investigated. FD could lead to the best quality but took the longest time, and AD product quality was too poor. VMD was introduced to combine with FD to get acceptable quality and reduce drying time. In order to get optimal technique parameters, an RSA experiment was carried out. The optimal technique parameters of combination drying of FD-VMD were 45% conversion point, 20–30 kPa chamber pressure, and 350–450 W microwave power. Compared with Freeze Drying (FD), Air Drying (AD)-Vacuum Microwave Drying (VMD) could reduce the drying time to half and maintain good product quality.     

Study on a Combination Drying Technique of Sea Cucumber

To develop a highly efficient drying technique for sea cucumber, the effects of different drying methods on the drying procedure and product quality were investigated. FD could lead to the best quality but took the longest time, and AD product quality was too poor. VMD was introduced to combine with FD to get acceptable quality and reduce drying time. In order to get optimal technique parameters, an RSA experiment was carried out. The optimal technique parameters of combination drying of FD-VMD were 45% conversion point, 20-30 kPa chamber pressure, and 350-450 W microwave power. Compared with Freeze Drying (FD), Air Drying (AD)-Vacuum Microwave Drying (VMD) could reduce the drying time to half and maintain good product quality.     

Comparative study on the flavonoids extraction rate and antioxidant activity of onions treated by three different drying methods

Onions, rich in flavonoids, with antioxidant, antibacterial, and other biological activities, are often used as extraction of raw materials to obtain health products with high flavonoids content. However, the amount of raw material consumption is large due to low yield of extracts from fresh onions. As a result, dried onions often are used as extraction materials. The effects of air drying (AD), freeze-drying (FD), and microwave freeze-drying (MFD) on the flavonoids extraction yield of onions were investigated. The most effective and economical method was hot AD. On the other hand, the flavonoids extraction rate of onions dried by MFD was the fastest. FD could also obtain high extraction rate, but it cost the highest energy consumption. In order to obtain relatively rapid, economic, and effective extraction of onion flavonoids, onions can be dried by MFD or AD method.     

The Effect of Glass Transition Temperature on the Procedure of Microwave–Freeze Drying of Mushrooms (Agaricus bisporus)

Freeze drying (FD) yields the best quality of dried mushroom but at the cost of a long drying time and high overall cost. Air drying (AD) gives an unacceptably poor quality product. To achieve faster drying along with a high-quality product, a microwave–freeze drying (MFD) technique was developed to dry mushrooms. The relationship between dried mushroom quality and the glass transition temperature during the MFD process was studied to optimize the MFD process. According to the change tendency of the glass transition temperature of mushroom during MFD, a step-down microwave loading scheme for the MFD process was developed to obtain good product quality.