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Empirical Modeling and Kinetic Study of Microwave Drying Process
Published in Kailas L. Wasewar, Sumita Neti Rao, Sustainable Engineering, Energy, and the Environment, 2022
Ruta D. Khonde, A. Waheed Deshmukh, Abdul Rahim Sheikh, Mayuresh V. Shivramwar
Drying is one of the prime preservation techniques for extending the shelf life of many food items and all the agricultural products [1], since drying prevents decay of material by micro-organisms. The drying process is a combination of thermo-physical and biochemical processes consisting of heat and mass transfer that takes place simultaneous between the material surface and surrounding medium. Generally, drying refers to an operation during which water content is removed from a wet solid material by thermal means. The process evolves the water content from a wet solid into an unsaturated gas phase. The main reasons for drying food are to prevent the growth and activity of micro-organisms and hence to preserve the food, and to reduce the weight and bulk density of food for cheaper transport and storage.
Freeze Drying and Microwave Freeze Drying as Encapsulation Methods
Published in Magdalini K. Krokida, Thermal and Nonthermal Encapsulation Methods, 2017
Vasiliki P. Oikonomopoulou, Magdalini K. Krokida
Drying is a physical process used for the removal of water from various materials. Drying processes are used for the reduction of weight and volume of the products, helping with storage and transportation, and reducing the relative costs (Maroulis and Saravacos 2003, Marques et al. 2006). In food industry, drying was firstly applied for the dehydration of vegetables and nowadays its use has been extended to a wide variety of products (Barbosa-Canovas and Vega-Mercado 1996). Drying contributes to the extension of products’ shelf-life. The reduction of water activity (below 0.5) limits the development of pathogens and spoilage microorganisms and reduces the enzymatic activity and chemical reactions inside the materials. Apart from being used as a dehydration and preservation method, drying can also be applied for the protection of bioactive compounds by their encapsulation in a stable matrix.
Drying of Agricultural Crops
Published in Guangnan Chen, Advances in Agricultural Machinery and Technologies, 2018
D. M. C. C. Gunathilake, D. P. Senanayaka, G. Adiletta, Wiji Senadeera
Drying is a major operation in the agricultural and food industry. It is often used as a primary operation for preservation of food materials, or as a secondary process in some manufacturing operations. Drying, a higher energy-consuming process, is also often practiced in the industry using direct thermal energy from the sun or driers and ovens. From the viewpoint of preservation of energy, it is desirable to store food at ambient conditions. This can be achieved by drying operations which reduces moisture content and water activity to prevent spoilage under long-term storage conditions. Key benefits of drying are an increased shelf life and a reduction of product volume and weight, which facilitates easy storage and transportation.
Optimisation techniques for solar drying systems: a review on modelling, simulation, and financial assessment approaches
Published in International Journal of Sustainable Energy, 2023
Baibhaw Kumar, Gábor Szepesi, Zoltán Szamosi
Optimised by efficiency and working conditions, the dryers could help the farmers significantly enhance their revenue. There are two broad classifications of solar dryers based on airflow: the active type (forced convection) and the passive type (natural convection). The user needs to understand the drying requirements of the product before selecting and fabricating the solar dryer (Sharma, Chen, and Vu Lan 2009). Conduction, convection, and radiation are the three basic modes of heat transfer. Solar dryers primarily work on the combinations of these modes of heat transfer. Several factors are vital in designing or fabricating solar dryers: portable design, thermally efficiency, and cost-effectiveness. A study by Chavan et al. (2021a) reveals that a conduction mechanism could consolidate the innovations in solar drying techniques in the case of natural convective and direct-type dryers. Airflow and temperature are the most important parameters affecting the drying phenomenon, among several other factors. The other parameters, which govern the optimisation, could be the sun’s radiation, the air’s humidity, the load of product, and resistance to airflow. Spoilage of crops and food products is a big concern for rural farmers with limited sources. Thus, a user-friendly low-cost solar drying solution could be a boon for them. Air and temperature control circulation should be of prime concern in manufacturing such dryers. Hence, the dryers, which are scientifically optimised, are better performing (Prakash and Kumar 2013).
Drying of food industry and agricultural waste: Current scenario and future perspectives
Published in Drying Technology, 2023
Winny Routray, Rahul Chetry, B. S. Jena
Some of the major advantages of drying include the consumption of less storage space and an increase in the shelf life of the commodity. In certain cases, raw materials might not be transferable in their original form, which might force the industries to locally dispense/sell the wastes and byproducts, mainly for low-end applications such as animal feed or manure production. However, as drying increases the stability of the processed raw materials, it provides the opportunity for conversion of the waste to value-added products or increases in their economic value attributed to the elongated usability and storage stability. Also, spoilage is prevented by drying, which can be much faster in the case of animal-based products due to the predominant microbial and enzymatic processes that render them completely unsuitable for further application.
Experimental study on the hygrothermal dynamics of peanut (Arachis hypogaea Linn.) in the process of superposition and variable temperature drying
Published in Drying Technology, 2021
Shiyu Zeng, Zhilong Du, Weiqiao Lv, Dong Li, Dianbin Su, Huangzhen Lv
The temperature and material thickness are the main factors that affect the drying process. The temperature and material thickness were set as variables, while the air velocity remained unchanged in the STVD process. The prepared raw materials were divided into 4 groups, with 1500 g of peanuts allocated for each group. In order to increase the drying efficiency and save energy, drying was carried out according to the following three stages of the SVTD process. The moisture content point at the end of each drying stage was selected according to the change of moisture in the peanuts. Most of the free water was lost during the drying process when its dry base moisture content decreased from the initial moisture content to 25%. In the process of reducing the dry base moisture content from 25% to 15%, most of the water lost in the drying process was immobilized water. And 10% is the dry basis moisture content of peanuts can be stored at room temperature. When the dry basis moisture content of materials reached approximately 25%, the first stage drying process was completed. The dry basis moisture content of materials reached approximately 15%, the second stage drying process was completed. And when the dry basis moisture content reached 10%, the drying process was stopped. The main parameters are shown in Table 1.