Onwude Daniel I, Hashim Norhashila, Janius Rimfiel B, Nawi Nazmi Mat, Abdan Khalina
Dept. of Biological and Agricultural Engineering, Faculty of Engineering, Univ. Putra, Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
Dept. of Agricultural and Food Engineering, Faculty of Engineering, Univ. of Uyo, 52021, Uyo, Nigeria.
Compr Rev Food Sci Food Saf. 2016 May;15(3):599-618. doi: 10.1111/1541-4337.12196. Epub 2016 Feb 4.
The drying of fruits and vegetables is a complex operation that demands much energy and time. In practice, the drying of fruits and vegetables increases product shelf-life and reduces the bulk and weight of the product, thus simplifying transport. Occasionally, drying may lead to a great decrease in the volume of the product, leading to a decrease in storage space requirements. Studies have shown that dependence purely on experimental drying practices, without mathematical considerations of the drying kinetics, can significantly affect the efficiency of dryers, increase the cost of production, and reduce the quality of the dried product. Thus, the use of mathematical models in estimating the drying kinetics, the behavior, and the energy needed in the drying of agricultural and food products becomes indispensable. This paper presents a comprehensive review of modeling thin-layer drying of fruits and vegetables with particular focus on thin-layer theories, models, and applications since the year 2005. The thin-layer drying behavior of fruits and vegetables is also highlighted. The most frequently used of the newly developed mathematical models for thin-layer drying of fruits and vegetables in the last 10 years are shown. Subsequently, the equations and various conditions used in the estimation of the effective moisture diffusivity, shrinkage effects, and minimum energy requirement are displayed. The authors hope that this review will be of use for future research in terms of modeling, analysis, design, and the optimization of the drying process of fruits and vegetables.
水果和蔬菜的干燥是一项复杂的操作，需要大量的能量和时间。在实际操作中，水果和蔬菜的干燥可延长产品保质期，并减少产品的体积和重量，从而简化运输。偶尔，干燥可能会导致产品体积大幅减小，进而降低存储空间需求。研究表明，单纯依赖实验干燥方法，而不从数学角度考虑干燥动力学，会显著影响干燥机的效率，增加生产成本，并降低干燥产品的质量。因此，运用数学模型来估算农产品和食品干燥过程中的干燥动力学、行为及所需能量变得不可或缺。本文全面回顾了自2005年以来水果和蔬菜薄层干燥的建模情况，特别关注薄层理论、模型及应用。同时也突出了水果和蔬菜的薄层干燥行为。展示了过去10年中水果和蔬菜薄层干燥最常用的新开发数学模型。随后，列出了用于估算有效水分扩散率、收缩效应和最低能量需求时所使用的方程及各种条件。作者希望这篇综述能对水果和蔬菜干燥过程的建模、分析、设计及优化的未来研究有所帮助。
