Characteristics of thin-layer drying and rehydration of nata de coco

Nata is white gelatinous bacterial cellulose produced by Acetobacter aceti ssp. xylinum through fermentation of coconut water. Drying behaviour of nata de coco was conducted with a hot air dryer for a temperature range of 50-90 degrees C. The experimental data obtained were fitted into seven empirical and/or semi-theoretical thin-layer drying models using nonlinear regression analysis. Results showed that Logarithmic model, Wang and Singh model fitted better than Verma et al. model although all these three models were suitable for predicting the drying process of nata de coco. The rehydration capacity was lost severely when the moisture content of the samples was nearly zero, but it can almost rehydrate to its initial state when the moisture content was above 8%. The drying kinetic properties and rehydration capacity of nata de coco indicated that most of the moisture in nata de coco was free water.