【作者】 王宁；

【导师】 刘文秀； 李凤城； 杜志龙；

【作者基本信息】 中国农业机械化科学研究院 ， 农产品加工及贮藏工程， 2010， 硕士

【摘要】 我国新疆杏固形物含量高、品质好,适合加工制干之用,但由于当地用露天摊晒得到的杏干存在的品质、卫生差等问题,本文通过低温干燥的方法对南疆杏的干燥特性和干燥模型进行了研究,主要进行了以下探讨：对新疆阿克陶地区两种杏赛买提和索克亚格勒克在果实第二次快速生长期末的可溶性固形物、有机酸含量的动态变化进行了测定。结果表明,两种杏在此过程中的可溶性固形物含量有所增加,有机酸含量有所下降,固酸比有显著增加,且索克亚勒克固酸比增加幅度比赛买提更大。在设计制作试验台基础上,采用二次通用旋转组合设计的方法以干燥风速、干燥温度和杏果实的采摘日期(在这里用杏树停水后的天数表示)为因素对杏进行低温薄层干燥试验,并对三个常用的干燥模型进行拟合比较。试验结果表明Wang-Singh模型最能描述杏的干燥过程。在试验范围内,杏的有效扩散系数随温度上升而增加,随采摘日期增加而减小,随风速升高而增加,但风速增到一定数值时,杏的有效扩散系数随风速失去变化规律。在试验范围内,温度对色泽的影响极不显著；风速仅对白度L*有较小影响,采摘日期对白度L*、红度a*、黄度b*的影响均较大。对传统晾晒法、低温干燥法和烘晒结合法三种干燥方法干制的杏干进行了品质的对比。结果表明：传统晾晒法得到的杏干颜色最好,但硫残量过高；其内部组织结构较差,主要是干燥时温度过高、强度较大,杏失水过快的原因。对于硫残量较低的低温干燥法和烘晒结合法相比,在颜色方面和组织结构方面低温干燥法有一定优势。更多还原

【Abstract】 Apricot of xinjiang has good quality of high solids content,but the phenomenon of poor quality and bad health is quite common in dried apricot production. In order to solve these problems, thin layer drying experiments of apricot in low temperature were carried out on rotation design. The drying characteristic and the drying model of apricot were studied. In this paper the maim aspects were investigated as follows:In the period of second fast growth, the changes of soluble solids and organic acids content were studied in saimaiti and suokeyaleke. The experiments showed that the soluble solids increased gradually with the fruit maturing and the organic acids reduced during the period. The solid-acid ratio increased significantly.Based on the test bed, thin layer drying experiments of apricot in low temperature were carried out on rotation design. The drying characteristic and the drying model of apricot were studied based on temperature, velocity of drying medium and maturity. And three thin lay mathematical drying models were compared to their coefficients of determination. The results indicated that Wang-Singh model could satisfactorily describe the change regulation of moisture ratio during the drying process of apricot. The values of effective diffusion coefficient increased with the temperature in the range of 30-40℃and velocity of 1-2.2m/s,but reduced with soluble solids content increasing. In the test, temperature has no influence on color, velocity has a little influence only on L*, but maturity has notable influence on L*, a* and b*.Dried apricots made by traditional drying, low temperature drying and sun-roasting drying were compared. The results indicated that apricots made by traditional drying had a better color but poor internal organization. This is the result of excessive sulphuring and high drying strength. Compared low temperature drying to sun-roasting drying with low residual sulfur, low temperature drying was better in color and organizational structure.更多还原