Optimization of Process Conditions for Moisture Ratio and Effective Moisture Diffusivity of Tomato during Convective Hot‐Air Drying using Response Surface Methodology

Author(s):  
Obafemi Ibitayo Obajemihi ◽  
Joshua Olanrewaju Olaoye ◽  
Jun‐Hu Cheng ◽  
John Olusegun Ojediran ◽  
Da‐Wen Sun
2016 ◽  
Vol 62 (No. 1) ◽  
pp. 15-23 ◽  
Author(s):  
H. Samimi Akhijani ◽  
A. Arabhosseini ◽  
M.H. Kianmehr

Mathematical modelling and effective moisture diffusivity of tomato (Lycopersicon esculentum) was studied during hot air solar drying. An experimental solar dryer with a swivel collector was used for experiments. The collector followed the solar radiation using a precious sensor. Drying experiments were performed in a thin layer hot air drying at slice thicknesses of 3, 5 and 7 mm and air velocities of 0.5, 1 and 2 m/s. The experimental data were fitted to different mathematical moisture ratio models and the Page model was selected as the best model according to correlation coefficient R<sup>2</sup>, chi-square &chi;<sup>2</sup> and root mean square error (RMSE) parameters. The maximum values of moisture diffusivity was&nbsp;6.98 &times; 10<sup>&ndash;9</sup> m<sup>2</sup>/s at air velocity of 2 m/s and slice thickness of 7 mm while the minimum value of the moisture diffusivity was 1.58 &times; 10<sup>&ndash;9</sup> m<sup>2</sup>/s at air velocity of 0.5 m/s and slice thickness of 3 mm.


2018 ◽  
Vol 187 ◽  
pp. 01002 ◽  
Author(s):  
Boochita Wongpanit ◽  
Sumitta Chotikamas ◽  
Supacharee Roddecha ◽  
Prapakorn Tantayotai ◽  
Malinee Sriariyanun

Herbal compress ball is currently one of important products of Thailand for exporting sales worldwide. It is used in Thai traditional medical treatment and spa to reduce muscle pain and relaxation. This research aimed to generate the mathematical models representing the behaviors of herbs in hot air drying to extend shelf life for exporting sales. Here, six types of herbs, including Prai (Zingiber cassumunar Roxb.), Turmeric (Curcuma longa Linn.), Lemongrass (Cymbopogon citratus), Kaffir lime (Citrus hystrix), Soap Pod leaves (Acacia concinna) and Tamarind Leaves (Tamarindus indica Linn.) were dried in different temperature at 60, 70, and 80 °C. Fours drying models, Page, Henderson and Pabis, and Logarithmic and Fick's second law equation were applied with experimental data of drying herbs to predict the rate of diffusion of water. The results showed that the Page model is the most suitable model due to the highest decision coefficient (R2) but the lowest Root Mean Square Error (RMSE). The effective moisture diffusivity (Deff) of the herbs in herbal compress ball was increased with increased the drying temperature. The size of the herb particle translated inversely with effective moisture diffusivity (Deff) value.


2020 ◽  
Vol 20 (9) ◽  
pp. 701-709
Author(s):  
Osman Ismail ◽  
Ozlem Gokce Kocabay

In this study, drying kinetics, chemical composition and surface color for fillets samples, namely Rainbow trout (Oncorhynchus mykiss) subjected to combined drying (ultrasonic assisted vacuum drying) and hot-air drying were compared at full length between 50-70°C. Drying process carried out entirely in the falling rate period. The results suggested that the moisture content was influenced by the combined drying method and the drying temperature. The shortest drying time was obtained using combined drying method at 70°C. The combined drying method made shorter the drying process and enhanced the effective moisture diffusivity by comparison with hot-air drying method. The activation energies were observed using a modified Arrhenius type equation as of 2.392 and 4.83 kW kg-1 for combined and hot-air drying, respectively. Quality characteristics of fillets samples were specified as physical (moisture content, color values) and chemical (protein, fat and ash). Seven different drying models were considered for moisture ratios using nonlinear regression analysis. The consequences of regression analysis stated that the Midilli et al., model best fits data set. According to the results, the highest effective moisture diffusivity was determined in the fillets dried with the ultrasonic assisted vacuum drying method and they increased with increasing drying temperatures. Ultrasonic treatment accelerated the vacuum drying process for the fillets. Also, the ultrasonic assisted vacuum drying method is a better technology to preserve the original material and prevent thermal damage.


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