Artificial Neural Network Modeling of Drying Kinetics and Color Changes of Ginkgo Biloba Seeds during Microwave Drying Process

Ginkgo biloba seeds were dried in microwave drier under different microwave powers (200, 280, 460, and 640W) to determinate the drying kinetics and color changes during drying process. Drying curves of all samples showed a long constant rate period and falling rate period along with a short heating period. The effective moisture diffusivities were found to be 3.318 x 10(-9) to 1.073 x 10(-8)m(2)/s within the range of microwave output levels and activation energy was 4.111 W/g. The L* and b* values of seeds decreased with drying time. However, a* value decreased firstly and then increased with the increase of drying time. Artificial neural network (ANN) modeling was employed to predict the moisture ratio and color parameters (L*, a*, and b*). TheANNmodel was trained for finite iteration calculation with Levenberg-Marquardt algorithm as the training function and tansig-purelin as the network transfer function. Results showed that the ANN methodology could precisely predict experimental data with high correlation coefficient (0.9056-0.9834) and low mean square error (0.0014-2.2044). In addition, the established ANN models can be used for online prediction of moisture content and color changes of ginkgo biloba seeds during microwave drying process.