Exergy and Energy Analyses of Microwave Dryer for Cantaloupe Slice and Prediction of Thermodynamic Parameters Using ANN and ANFIS Algorithms

The study targeted towards drying of cantaloupe slices with various thicknesses in a microwave dryer. The experiments were carried out at three microwave powers of 180, 360, and 540 W and three thicknesses of 2, 4, and 6 mm for cantaloupe drying, and the weight variations were determined. Artificial neural networks (ANN) and adaptive neuro-fuzzy inference systems (ANFIS) were exploited to investigate energy and exergy indices of cantaloupe drying using various afore-mentioned input parameters. The results indicated that a rise in microwave power and a decline in sample thickness can significantly decrease the specific energy consumption (SEC), energy loss, exergy loss, and improvement potential (probability level of 5%). The mean SEC, energy efficiency, energy loss, thermal efficiency, dryer efficiency, exergy efficiency, exergy loss, improvement potential, and sustainability index ranged in 10.48–25.92 MJ/kg water, 16.11–47.24%, 2.65–11.24 MJ/kg water, 7.02–36.46%, 12.36–42.70%, 11.25–38.89%, 3–12.2 MJ/kg water, 1.88–10.83 MJ/kg water, and 1.12–1.63, respectively. Based on the results, the use of higher microwave powers for drying thinner samples can improve the thermodynamic performance of the process. The ANFIS model offers a more accurate forecast of energy and exergy indices of cantaloupe drying compare to ANN model.

Design and Performance of Scaled-Up Microwave Dryer for Seaweed Drying

Direct sunlight is commonly used to dry fresh seaweed by artisanal farmers in Indonesia due to its low cost and ease of handling. Nevertheless, this method poses some drawbacks such as lengthy duration, weather dependency and quality degradation. The application of microwave technology in food processing has progressed dramatically, including in the drying process. The microwave drying method is more efficient and can shorten the processing time. This study aimed to describe a large-scale microwave dryer (MD) design and performance to assist the fresh seaweed drying process. The design concept applies microwave energy with a volumetric heating feature to accelerate the seaweed drying process without damaging its functional groups. The MD dimensions were 2410 (l) x 270 (w) x 210 (h) mm with a dryer capacity of up to six kilograms, an enlarged cavity and multiple magnetrons. The main components of the MD were cavity, air circulation system, drying system and control system. According to the performance testing, the MD’s optimum performance was at a power level setting of P7 and six kilograms load. At this setting, we obtained a dried seaweed with a moisture ratio of 0.68±0.05, drying rate of 30.29±1.32 g/min, specific energy consumption of 3.96±0.08 MJ/kg H2O and energy efficiency of 58.45±2.65%. The total power of the P7 setting operation required 2.00 kW. Fourier-Transform Infrared (FTIR) spectra showed that the functional groups of the dried seaweed were unaltered.

Mathematical modeling of thin layer microwave drying of Jaya fish (Aspidoparia jaya)

The effect of microwave power levels on the drying attributes of Jaya fish ( Aspidoparia jaya) in a microwave dryer was investigated in this study. Microwave power levels of 100, 180, 300, and 450 W were used to dry 50 g of fish samples, and the drying kinetics were evaluated. Higher microwave power levels resulted in faster drying when increased from 100 to 450 W. The moisture ratio of fish during drying was calculated, and the data obtained were applied to 5 well known thin-layer mathematical models of drying, namely Approximate diffusion, Modified Henderson and Pabis, Two-Term, Logarithmic, and Midilli et al. model. Model constants and coefficients were calculated by nonlinear regression techniques. All the models were validated using statistical parameters namely; Coefficient of determination (R2), Root Mean Square Error (RMSE), Chi-square (χ2), and Standard Sum of Error (SSE). The Midilli et al. model gave an excellent fit to the experimental data of all the models evaluated. The effective diffusivity was calculated using Fick’s diffusion equation, and the value varied from 1.40 × 10−9 to 1.08 × 10−8 m2/s. The activation energy and the diffusivity constant were found to be 4.656W/g and 1.22 × 10−8 m2/s, respectively.

Evaluation of sensory attributes of cauliflower slices under various pre-treatment and tray drying and microwave power drying condition

Cauliflower is one of the most important winter vegetable crop of india. Dehydrated cauliflower can be used to enhance the taste and nutritional value of various product such as vegetable soup, canned and extruded products etc.Experimental study was conducted to evaluate cauliflower slices using tray drying and microwave power drying techniques. Pre treatment of cauliflower slices as unblanched , blanched and blanched with kms and dried at different temperature( 45, 55 and 65°C ) and micro wave at different power level ( 20 W,40 W and 60 W ).The physio-chemical characteristics were evaluated just after preparation of cauliflower slices. Sensory characteristics (colour, flavour, taste, texture and overall acceptability) were evaluated for pre-treated cauliflower slices which dehydrated in tray dryer at 45, 55 and 65°C temperature and in microwave power dryer at 20, 40 and 60 W power. Sensory evolution was done using hedonic rating test method to measure the consumer acceptability. Results showed that highest score was obtained as 7.9 for colour at 65°C in KMS blanched condition whereas highest score for taste was obtained as 7.9 at 65°C in blanched condition in tray dryer. The maximum value of flavour (8.0) was obtained at 65°C in blanched condition whereas highest value of texture (7.9) at 65oC in blanched condition in tray dryer in microwave dryer, the highest values of colour (7.9) was obtained at 60W in kms blanched condition where as highest value of taste (7.9) at 60 W in unblanched conditions .The highest score of flavour (8.1) and texture (7.9) were found at 60 W in kms blanched condition in microwave power drying. Overall acceptability score was highest (7.92) in microwave power drying than tray drying (7.85) in kms blanched sample at 60 W power and 65°C temperature drying, respectively. Microwave power drying was found most suitable for kms blanched cauliflower slices at 60 W power level.