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Subbulakshmi, 2005). Ripened sohiong fruits are drupe of dark purple color with a smooth surface. The unique color of sohiong fruits is due to the accumulation of anthocyanin, which are essential determinants for the color of many roots, leaves, stems, vegetables, fruits, and seeds (Lin-Wang et al., 2010). Sohiong is a spherical shaped fruit, and the ripened fruits are consumed in raw form. The pulp and juice have a purple color and are commonly used to prepare wine, jam, squash, ready-to-serve (RTS) beverages. The fruit is a rich source of vitamin C, β-carotene, and iron (Agrahar-Murugkar & Subbulakshmi, 2005). It has the potential in the food and pharmaceutical industries (Rymbai et al., 2016). This

The purpose of this study was to develop a predictive three‐dimensional analytical model for predicting the temperature profile during microwave and convective drying of dragon fruit. A combined electromagnetic (Maxwell's equation) and heat transfer model was used for modeling of microwave drying. This heat transfer modeling is applicable to describe the thermal dissipation during the microwave and convective drying of agricultural produces. In this process, the dragon fruit cube of 15 mm was dried at a microwave power of 200, 400, and 600 W during the microwave drying process and hot air temperature of 60°C during the convective drying process. During microwave drying, the core or center temperature was maximum compared with the temperature at the surface of the dragon fruit cube. The predicted temperature at the center of the dragon fruit cube exposed to the microwave power of 200, 400, and 600 W for 60 s of drying time was 34.67, 44.34, and 54.02°C, respectively. In convective drying, the temperature at the edges was higher than the temperature at the center point of the dragon fruit cube. During convective drying, the fruit sample attained the maximum temperature of 60°C after being exposed to hot air for 8 min. The RMSE and χ2 values between experimental and model projected values were less than 0.988 and 0.029 in microwave drying and less than 0.891 and 0.018 in convective drying, indicating that the model projected values were in good agreement with the experimental values. Practical Applications The importance of thermal processes in deciding the safety and quality of food products is emergent. This model can predict food product temperature distribution during the hot air drying and microwave drying of Dragon fruit cubes. The economy of the drying process is often influenced by the nature and operation of these processes and hence modeling of the drying process is a crucial factor for the industry. These results can be used to quantify heat and moisture distribution, as well as to monitor the drying process of fruits and vegetables, saving energy and time.

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The effect of ultrasonication on osmotic dehydration of dragon fruit (Hylocereus undatus) slices was investigated using a feed forward backpropagation neural network in this study. The four process variables were ultrasonic power (XUP: 100–300 W), ultrasound temperature (XUT: 30–50°C), osmotic solution concentration (XSC: 40–60°Brix), and liquid to solid ratio (XLS: 8:1–12:1 ml/g). Under different combinations of independent variables, the water loss (YWL), solid gain (YSG), and change in color (Y∆E) were evaluated. The ANN architecture consists of 4, 9, and 3 neurons in the input, hidden, and output layer, respectively. The three independent variables of ultrasound‐assisted osmotic dehydration XUP, XUT, and XSC found to have a positive effect on the three responses water loss, solid gain, and change in color. The liquid to solid ratio was revealed to have a negative effect on color change and a positive impact on response water loss and solid gain. The output parameters of the ANN model (weights and bias) were integrated with genetic algorithm (GA) for the optimization purpose, and the best combination was picked based on the fitness value (FV). The optimal ultrasound‐assisted osmotic dehydration condition obtained using integrated ANN‐GA was 235 W, 38.74°C, 56°Brix, and 10.5 ml/g. The relative deviation between the experimental and integrated ANN‐GA model predicted values for water loss, solid gain, and color change values under optimum conditions was less than 6.880%, suggesting that the predicted values for response were in good agreement with the experimental data. Practical applications The article describes the synergistic influence of sonication power and temperature on the osmotic dehydration of dragon fruit slices. Ultrasound‐assisted osmotic dehydration (USOD) prevents enzymatic and oxidative browning, preserving the color. In dragon fruit slices flavor retention increases when sugar syrup is used as an osmotic agent. Furthermore, the fruit pieces absorb sugar and eliminate acid, resulting in a sweeter product than a conventionally dried product. The results showed that ultrasound assisted osmotic dehydration removed water from dragon fruit more rapidly at a lower temperature, keeping color, aroma, nutritional value, and flavor components. The combined impact of ultrasound and temperature also lowered the water activity of fruit and enhanced the product's storage life significantly.