【作者】 张力伟；

【导师】 张伟；

【作者基本信息】 黑龙江八一农垦大学 ， 农产品加工与贮藏工程， 2010， 硕士

【摘要】 香菇营养丰富,具有较高的营养价值和医疗保健功效。香菇质地细嫩,采收后鲜度迅速下降,从而会引起开伞、菌褶褐变、菇体萎缩等,影响其风味和商品价值,故香菇不易贮存。真空冷冻干燥是一种新型的干燥技术,可以延长产品保存期,最大程度保留新鲜香菇的色、香、味及营养成分,且脱水彻底、复水性好。本研究以新鲜香菇为实验材料,测定其共晶点和共熔点。以新型冻干机为基础,对香菇真空冷冻干燥工艺进行研究。通过分析真空冷冻干燥过程和机理,利用质热交换理论,确定物料厚度、预冻速率、干燥仓压力和加热板温度为影响香菇真空冷冻干燥试验的主要因素。通过单因素实验以及四因素五水平的二次回归正交试验确定各因素的取值范围,以及通过对建立的数学模型的分析,经t检验方差分析得到,各因素对干燥时间的影响大小为:预冻速度>干燥仓压力>物料厚度>加热板温度。利用SAS软件进行二次旋转回归试验设计结果分析,进行工艺参数优化处理,得到了最佳工艺条件:干燥仓压力61.8Pa,加热板温度61.7℃,预冻速度2.58℃/min,物料厚度6.78mm。冻干时间7.27h。同时,为了进一步验证香菇干燥后的品质,设计合理干燥工艺参数,本文对不同干燥方法生产的香菇干制品进行了对比试验研究,真空冷冻干燥在产品的感官指标,复水情况和营养成分含量方面上优于热风干燥。更多还原

【Abstract】 Letinus edodes are nutritious which have high nutritional value and health effects. Letinus edodes have tender texture, and then their freshness decreased rapidly after harvest, which will lead to parachute, gill browning, fruiting bodies atrophy, affecting taste and commercial value,so it is not easy to keep in storage. Vacuum freeze-drying is a new drying technology,keep their color, aroma, taste and nutritional ingredients to a large extent , and completely dehydrated, rehydrate well.The article determined the eutectic point and eutectic point using fresh Letinus edodes as the material.It research the vacuum freeze-drying process on the base of new freeze dryer.Through analyzing the mechanism of vacuum freeze-drying process and the theory of heat exchange,it it defined the main factors of Letinus edodes vacuum freeze-drying process: material thickness, cooling rate, pressure and heating temperature by analyzing the vacuum freeze-drying process and mechanism. By single factor experiments and the four factors and five levels of the quadratic regression orthogonal experiment, analysing the model and t test analysis of variance, we got each factor antagonism the yield of starch size: cooling rate>drying chamber pressure> material thickness>heating temperature. Using SAS software to analysis the results of second rotation regression test and optimiz process parameters, we got the optimum conditions: drying chamber pressure 61.8Pa, heating temperature 61.7℃, pre-freezing rate of 2.58℃/min, material thickness of 6.78mm . Drying time 7.27h. At the same time, in order to verify the quality of dried Letinus edodes further and design reasonable dried parameters, the paper do the compared experiment of Letinus edodes which produced by different drying methods ,it found: vacuum freeze-drying are better than hot air drying in the aspects of sensory indicators, rehabilitation of water conditions and nutrient content.更多还原