Janowicz Monika, Ciurzyńska Agnieszka, Lenart Andrzej
Department of Food Engineering and Process Management, Institute of Food Sciences, Warsaw University of Life Sciences, SGGW, 159c Nowoursynowska St., 02-776 Warsaw, Poland.
Foods. 2021 Oct 28;10(11):2605. doi: 10.3390/foods10112605.
The paper presents water diffusion coefficients as providing a significant contribution to the creation of a comprehensive database and knowledge of weight variation during the drying process of raw plant materials that is used for modelling the technological process and designing innovative products. Dehydration is one of the most widely used methods for improving the stability and durability of fruit and vegetables because it reduces water activity and microbial activity, and minimises the physical and chemical changes during storage. The considerable impact of pressure on heat exchange and weight during the convection drying process of osmotically pretreated apples is demonstrated. The course of the drying curves and the drying rate is determined by the use of pressures of 0.02 and 500 MPa. Varied pressure applied during osmotic impregnation significantly influences the value of the diffusion coefficient: the average determined for the entire course of the drying curve and the average determined in the intervals of the reduced water content. The lowest values of the average water diffusion coefficient are obtained for apples preboiled under overpressure conditions and, at the same time, the determined diffusion coefficients in the water content are characterised on the drying curve by a clearly decreasing course until the reduced water content reaches approximately 0.2.
本文提出，水分扩散系数对创建一个全面的数据库以及了解用于模拟工艺流程和设计创新产品的原料植物干燥过程中的重量变化具有重要意义。脱水是提高水果和蔬菜稳定性和耐久性最广泛使用的方法之一，因为它降低了水分活度和微生物活性，并使储存期间的物理和化学变化最小化。研究表明，压力对渗透预处理苹果对流干燥过程中的热交换和重量有显著影响。通过使用0.02和500MPa的压力来确定干燥曲线的过程和干燥速率。渗透浸渍过程中施加的不同压力会显著影响扩散系数的值：整个干燥曲线过程中确定的平均值以及含水量降低区间内确定的平均值。在超压条件下预煮的苹果获得的平均水分扩散系数最低，同时，在干燥曲线上，含水量降低时确定的扩散系数呈现明显下降趋势，直到含水量降低到约0.2。
