Effect of separation methods on the drying kinetics of organic pitaya (Hylocereus undatus [Haw.] Britton & Rose) seed

Organic pitaya seeds are rich in protein, lipids and bioactive compounds, but their separation from the pulp is a technological challenge. The objective of this study was to evaluate the effect of the seed-pulp separation method on the seeds' drying process. Three separation methods were evaluated: acid (AS), thermal (ES) and enzymatic (TS). After separation, the seeds were dried at 45 degrees C, and the kinetic curves, the drying rates, and the effective diffusion coefficient were determined. All treatments promoted the separation of the pulp from the seed, however, ES treatment promoted the best separation, which significantly affected the drying process. The observed effects were the decreased of the initial moisture content, reduced the drying rate by 6 times, and the diffusivity by 1.7 times when compared to the seeds obtained by the AS treatment. The constant rate period seemed to control the drying kinetics, and Page's semi-empirical model best fitted the experimental data.

Automated summary

This study evaluated the effects of different seed-pulp separation methods on the drying process of organic pitaya seeds, with thermal separation method showing the best results. The separation significantly influenced the drying process by decreasing moisture content, reducing drying rate, and affecting diffusivity.