共查询到20条相似文献,搜索用时 125 毫秒
1.
鱿鱼热泵-热风联合干燥节能研究 总被引:4,自引:0,他引:4
以热泵干燥阶段的温度、分阶段干燥的水分转换点、后期热风干燥阶段的温度为影响因素,以单位能耗除湿值(SMER)和总挥发性盐基氮值(T—VBN)两者的综合指标Y为最终评价指标进行响应面优化分析,得出了联合干燥最佳工艺参数:热泵干燥温度(X1=54.3℃)、水分转换点(X2=32.3%)和热风干燥温度(X3=43.5℃)。在最优工艺条件下比较HPD、HPD+AD、AD三种干燥方式下的样品品质和耗能,联合干燥得到的鱿鱼干品质高于热风干燥,而且降低了干燥能耗38.67%。 相似文献
2.
3.
4.
5.
6.
7.
8.
9.
10.
玉米干燥中应力裂纹的生成、扩展、检测和预防分析 总被引:5,自引:0,他引:5
针对谷物干燥过程中产生裂纹的类型和对粮食品质的影响作了概述。以玉米为例,就干燥工艺中热风温度、湿度、干燥速率、玉米初始含水率及玉米的种类、粒度、大小形状和内部结构以及干燥机的选型、冷却、缓苏等因素对玉米产生应力裂纹的影响进行了分析;介绍了裂纹产生的机理和检测方法,提出了减少裂纹的措施,并介绍了近年来该项技术的最新进展。 相似文献
11.
12.
The fluidized bed drying process of green peas was optimized using the response surface methodology for the process variables: drying air temperature (60–100°C), tempering time (0–60 min), pretreatment, and mass per unit area (6.3–9.5 g/cm2). The green peas were pretreated by pricking, hot water blanching, or chemical blanching. Product quality parameters such as rehydration ratio, color, texture, and appearance were determined and analyzed. Second-order polynomial equations, containing all the process variables, were used to model the measured process and product qualities. Rehydration ratio was influenced mostly by pretreatment followed by tempering time, temperature, and mass per unit area. Pretreatment and mass per unit area significantly affected color and texture. Higher levels of temperature and lower levels of tempering time and mass per unit area increased the rehydration ratio. The optimum process conditions were derived by using the contour plots on the rehydration ratio and sensory scores generated by the second-order polynomials. Optimum conditions of 79.4°C drying air temperature, 35.8-min tempering time, pretreatment of the once pricked peas with chemical blanching in a solution of 2.5% NaCl and 0.1% NaHCO3, and mass per unit area of 6.8 g/cm2 were recommended for the fluidized bed drying of green peas. At these conditions the rehydration ratio was 3.49. 相似文献
13.
Yingting Zhao Weiwei Wang Jingyi Xie Baodong Zheng Song Miao Y. Martin Lo 《Drying Technology》2017,35(13):1561-1570
This study evaluated the effects of a single-stage tempering treatment during microwave vacuum drying (MVD) on drying characteristics and quality of lotus (Nelumbo nucifera Gaertn.) seeds using two parameters: intermediate moisture content (IMC) and tempering temperature (4 and 25°C). Magnetic resonance imaging (MRI) was used to examine moisture migration and distribution in individual lotus seed during tempering. Results from MRI showed tempering could reduce the moisture gradient in lotus seeds during MVD. The tempering treatments led to increased moisture diffusivity (3.96–43.56%) and a shortened drying time (6.25–31.25%) when compared with continuous MVD. Furthermore, tempered samples exhibited a greater rehydration capacity, a limited overall color change, and increased amounts of taste-active amino acids when compared with nontempered lotus seeds. High IMC improved rehydration ratios of dried samples. Low tempering temperature provided favorable free amino acid content and desirable product color. 相似文献
14.
15.
固体聚合硫酸铁的制取及工艺优化研究 总被引:9,自引:0,他引:9
以绿矾为原料、KCIO3为氧化剂,研究了固体聚合硫酸铁的制取方法。考察了绿矾氧化及其产物聚合硫酸铁在真空干燥等过程中的原料加入方式、加入量、反应温度、反应时间、干燥温度、真空度以及时效等参数的影响。实验结果表明,在水量为25g、绿矾用量为350g、绿矾与硫酸摩尔比为1.0:0.1、反应温度在55~60之间、反应时间为90min、干燥固化温度为55~60、真空度为0.09MPa时,产品不仅盐基度较高,质量稳定,而且外形优美,色泽好。通过时效研究认为反应产物应直接进入干燥固化为好;最后通过正交试验,获得了优化的工艺条件。 相似文献
16.
Multi-stage intermittent drying of rough rice in terms of tempering and stress cracking indices and moisture gradients interpretation 总被引:1,自引:0,他引:1
In this study, multi-stage intermittent drying (MSID) of rough rice is considered based on stress cracking index (SCI), tempering index (TI), and total drying/tempering duration for Hashemi and Koohsar varieties experimentally and theoretically. The samples were dried at 60°C for 20, 40, and 60?min and tempered at 60°C for 40, 80, 120, 160, 200, and 240?min after each drying stage. Afterward, the completion of the tempering process was assessed using the TI along with analysis of moisture content kinetics by a simplified drying model. For both varieties, the SCI decreased significantly until continuing the tempering operation to certain durations and increased for longer drying durations in each drying stage. Considering the SCI and the total drying/tempering duration, the tempering durations of 200 and 160?min after 40?min drying in each stage were determined as the best performed conditions for MSID of Hashemi and Koohsar varieties, respectively. The results achieved by the TI were in conformity with those obtained by the mathematical model. It was concluded that the TI and simulation of surface moisture content on a kernel could be applied for estimating the time required for supplementation of the tempering process to eliminate moisture content gradients created inside the kernels during the drying process. 相似文献
17.
Somchart Soponronnarit Somboon Wetchacama Thanit Swasdisevi Ponglhep Chotijukdikuld 《Drying Technology》1999,17(6):1227-1238
The objective of this work is to study systematically how to decrease corn moisture content using processes consisting of fluidized bed drying, tempering and ambient air ventilation. Effects of drying, tempering and ventilation on moisture reduction and quality of dried corn in terms of stress crack, breakage and color are experimentally investigated. Experimental results show that stress crack depends on final moisture content of com. Tempering is found useful for increasing the quality of dried com after fluidized bed drying. The optimum tempering time is 40 minutes. Among the ambient air velocity ranging from 0.075 to 0.375 m/s, the appropriate velocity is 0.15 m/s. Final moisture content of com after ambient air ventilation is about 13.0 - 14.5 %(w.b.) with breakage and stress crack lower than 2% and 5% by wt., respectively. Slight change of color of dried corn is observed. 相似文献
18.
Low-field nuclear magnetic resonance (LF-NMR) has been increasingly popular as analytical tools for evaluating the dynamics of water mobility and distribution. In this study, dynamics of moisture mobility and constitution of surf clam during constant drying process and intermittent drying process were evaluated by LF-NMR, while the differences of physical and chemical indexes were measured. Intermittent drying improved the product quality of clam, such as moisture content, shear force, color indices, sugar content, peroxide value, thiobarbituric acid value, and the bulk water ratio, which were closely related with moisture distribution and microstructure. The moisture constitution of constant drying process and intermittent drying process were distinctly different. Tempering process reduced drying time and resulted in lower moisture content in dried surf clam. In the meanwhile, the boundary between A21 and A22 was acquired by LF-NMR, revealed that bound water and immobilized water transformed from each other. During tempering process, the myofibril stretched out, verifying that moisture approached a relatively homogeneous. In addition, R2 value reached 0.9897 and 0.9926 for calibration and validation, respectively, displaying good linear correlations between the T21 parameters and moisture content. This study interpreted the dynamics of water mobility and distribution on the proton level to explain the reason that tempering processes to improve physicochemical indexes of surf clam. 相似文献
19.
新鲜的榴莲蜜舍糖量高,水分多,是一种很容易腐烂的水果。为了能够延长贮存时间必须降低含水量。由于舍糖量高,当用传统的热风干燥进行干燥时,榴莲蜜表面会出现焦糖化。为了克服这个问题,在干燥的开始阶段应用间歇热泵干燥机,在干燥中期应用低温的除湿空气。结果表明:利用循环温度和递升温度干燥的样品湿含量可降低到0.081—0.110(g水/g干物质k此研究中用有限差分法来估算有效扩散系数值,较好地模拟了干燥动力学数据。就产品质量而雷,在循环温度干燥中减少热风干燥时间可生产柔软的干燥产品。而且,低温除湿空气的缓苏作用能减少干燥样品的总体颜色变化。 相似文献
20.
AN APPLICATION OF GLASS TRANSITION TEMPERATURE TO EXPLAIN RICE KERNEL FISSURE OCCURRENCE DURING THE DRYING PROCESS
* 总被引:5,自引:0,他引:5
Auke G. Cnossen Terry J. Siebenmorgen Wade Yang Rustico C. Bautista 《Drying Technology》2001,19(8):1661-1682
Fissure formation during rice drying is a major cause of rice milling quality reduction. This work has applied principles of polymer science in studying thermal and hygroscopic properties of rice kernels, particularly the glass transition temperature (Tg). This data was used to develop a hypothesis that explains the occurrence of rice kernel fissuring as a result of drying. The drying process was mapped onto a state diagram to illustrate the changes in state that a kernel could incur through drying and tempering operations. An experiment was designed to validate the hypothesis in which the effect of the Tg on rice drying and tempering in terms of milling quality was determined. Results showed that drying air temperatures up to 60°C and high moisture removal rates could be used without reducing the milling quality, as long as sufficient tempering was allowed at a temperature above the Tg of the rice. 相似文献