Optimization and Experiment of Hot Air Drying Process of Cyperus esculentus Seeds

To improve the drying efficiency, drying uniformity and germination rate after hot air drying of Cyperus esculentus seeds, this paper proposed a drying method that combines tempering and hot air drying. The drying curve of Cyperus esculentus was obtained by experiment. The influence of the drying method on the drying quality of Cyperus esculentus seeds and the trend of drying quality with the tempering process parameters (the tempering temperature, the moisture content of Cyperus esculentus at the beginning of tempering and the tempering duration) were analyzed by single-factor experiments. The regression models were established by star point design response surface methodology, and the relationships between the tempering process parameters and seed production quality indexes were analyzed. The results showed that the optimal combination of tempering process parameters was a tempering temperature of 24 °C, a moisture content of Cyperus esculentus at the beginning of tempering of 23%, and a tempering duration of 3 h. Under this combination, the tempering process increased the drying uniformity, germination rate and drying efficiency of Cyperus esculentus seeds by 21.122%, 4.205% and 22.832%, respectively. The error between the verification test value and the software optimization parameter value was acceptable. The study showed that the optimized tempering drying process significantly improved the drying quality of Cyperus esculentus seed production, and the results could provide a theoretical basis for production practices.