Hot Air Drying and Microwave-Assisted Hot Air Drying of Broccoli Stalk Slices (Brassica oleraceaL. Var.Italica)

Abstract

Drying characteristics of broccoli stalk slices under hot air drying (HA) and microwave-assisted hot air drying (MWHA) at temperatures of 40, 50 and 60C is presented. In addition, the color and shape changes of the dried sample were compared. Midilli et al. model showed a good agreement with the experimental data obtained for both drying systems. The calculated effective moisture diffusivity are varied from 2.92 3 10 28 to 7.91 3 10 28 m 2 /s under HA and 6.64 3 10 28 to 13.31 3 10 28 m 2 /s under MWHA. Less changes in color was observed under MWHA at lower temperature. Meanwhile, higher circularity of the shape was observed under HA. According to these results, MWHA promotes faster drying time with higher moisture diffusion; however, pre-treatment prior to this drying process is suggested to enhance the final dried product. PRACTICAL APPLICATIONSHabitually, just the edible floret of broccoli is consumed, leaving the stalk as crop remains. This part of the crop has the potential to be used as food since it has been identified as having many nutritional components. To develop this as a product, drying as a unit operation is essential. This work evaluates the drying behavior of different drying conditions of broccoli stalk. With these results, drying of broccoli stalk can be carried out by the food industry more effectively and efficiently.

Use of artificial intelligence for the estimation of effective moisture diffusivity, specific energy consumption, color and shrinkage in quince drying

“…It was also found that higher drying temperature resulted in larger heating energy leading to raising molecular water activity and raised D eff . The results of D eff value had a good agreement with the published values by other researchers (Ashtiani et al, ; Bhattacharya, Srivastav, & Mishra, ; Khoshtaghaza et al, ; Salim, Gariepy, & Raghavan, ; Wang, Li, et al, ).…”

Effect of microwave power on drying kinetics, structure, color, and antioxidant activities of corncob

“…Drying alters both physicochemical and nutritional characteristics of the agricultural crops by degrading and modifying the cellular components and promoting reactions between them, and concerted efforts are being made to modify such physicochemical changes in order to achieve a favorable result (Devahastin & Niamnuy, ). Quality of the final product depends largely on the choice of the technique: while low‐temperature processes such as freeze drying (FD) preserve most of the original characteristics of the product, high‐temperature processes such as hot air drying (HAD) destroy the squishy microstructure of plant products and degrade most of the thermolabile bioactive compounds(López et al, ; Md Salim, Gariépy, & Raghavan, ). Microwave drying (MWD), a novel dehydration technique based on electromagnetic (EM) radiation, offers a faster and more energy efficient alternative to these traditional techniques but is yet to be preferred by manufacturers for processing most of the agricultural crops because of its “destructive” effect on the food (Mandal, Mohan, & Hemalatha, ).…”

“…Figure 2a,b shows that there is good fit of experimental data for both MWD and FD and HAD processes with the Midilli et al's model. In earlier studies, Midilli et al's model also provided a better representation of MWD of broccoli stalk slices,leek, apple slices, and onion slices than other thin layer drying models(Md Salim et al, 2017;Süfer, Sezer, & Demir, 2017).…”

“…Drying alters both physicochemical and nutritional characteristics of the agricultural crops by degrading and modifying the cellular components and promoting reactions between them, and concerted efforts are being made to modify such physicochemical changes in order to achieve a favorable result (Devahastin & Niamnuy, 2010). Quality of the final product depends largely on the choice of the technique: while lowtemperature processes such as freeze drying (FD) preserve most of the original characteristics of the product, high-temperature processes such as hot air drying (HAD) destroy the squishy microstructure of plant products and degrade most of the thermolabile bioactive compounds (López et al, 2017;Md Salim, Gariépy, & Raghavan, 2017).…”

Drying Characteristics of Agricultural Products under Different Drying Methods: A Review

“…Combination drying methods (MW/IR drying assisted with hot air/VC, MW and IR combination) were introduced to compensate for the aforementioned drawbacks of individual drying methods. Several studies reported that combination drying methods promote faster drying time with rapid moisture diffusion and less change in color than in HA drying (Koné et al, 2013;Zhao et al, 2013;Wojdyło et al, 2014;Wu et al, 2014;Salim et al, 2016). Freeze-drying was considered a novel drying method in which frozen food or agricultural products could be dried by the sublimation of ice (Oetjen, 2000).…”