# Study of the Targeted Regulation of Rice Drying Characteristics and Quality
## 4 Conclusions  
A response regression model of rice drying under multiple factors was established using RSM with a central composite design, and a process reference chart was drawn. The results showed that the quadratic polynomial model of response quantity was statistically significant. Based on the analysis of the effects on drying characteristics and drying quality, the following conclusions were drawn:  
(1) Combined with the analysis of Design-Expert software, hot air temperature, hot air humidity, initial moisture content, hot air velocity, and slow-recovery ratio had significant effects on many indicators of rice drying efficiency and quality (\(p\) < 0.05). The initial moisture content had no significant effect on the fatty acid value. The hot air temperature had no significant effect on the germination rate, and the hot air temperature and slow-recovery ratio had no significant effect on the change in protein quality (\(p\) > 0.05). There were certain interactions among multiple factors. At the \(p\) < 0.05 level, TMC had a significant effect on net drying time, total drying time, and waist burst increase rate. T*TR had a significant interaction with total drying time, and RHTR had a significant effect on net drying time and waist burst increase rate. RH*MC had a significant effect on the waist burst increase rate. The effects of the other indicators were analyzed in detail in the main text. (2) Through the central composite experimental design, the optimal parameter combination of the slow-recovery drying process was confirmed as follows: hot air temperature, 43.138 \({}^{\circ}\)C; hot air humidity, 48.003%; initial moisture content, 23.8%; hot air velocity, 0.7 m/s; slow-recovery ratio, 3.55. Under this parameter combination, the net drying time of rice after drying was 157.606 min, the increase rate of waist burst was 3.479%, the rice  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Indicators** & **Tial Group** & **T C** & **RH (\%)** & **MC (\%)** & **V (m/s)** & **TR** & **Predicted Value** & **Actual Value** & **Error** \\ \hline \multirow{4}{*}{ACP (\%)} & 1 & 51.2 & 36.2 & 22.4 & 0.57 & 3.3 & 5.04 & 5.21 & 3.33\% \\ \cline{2-10}  & 2 & 50.5 & 31.2 & 26.2 & 0.83 & 1.5 & 4.35 & 4.48 & 3  
percentage was 70.454%, the fatty acid value was 20.932 mg, the concentration of resistant starch was 195.259 \(\mu\)g/g, the germination rate was 94.151%, the protein mass fraction was 8.531 g/100 g, and the fat mass fraction was 2.372 g/100 g. Under this parameter combination, the dried rice showed good quality, and the relative error between the validation test results and the optimization results was 4.68%, indicating that the optimized process parameters could improve the rice drying quality. (3) Using the RSM regression model, a process reference chart with a process retrieval and prediction function was drawn. The chart can provide practical guidance for the parameter regulation of drying operations, useful references for the early processing technology of rice after production, and a theoretical basis for exploring the mechanism of change in rice quality. Conceptualization, [PERSON] and [PERSON]; methodology, [PERSON]; software, J.L. ; validation, [PERSON] and [PERSON]; formal analysis, [PERSON]; investigation, [PERSON]; resources, [PERSON]; data curation, J.L. ; writing--original draft preparation, [PERSON]; writing--review and editing, [PERSON]; project administration, [PERSON]; funding acquisition, Y.J. All authors have read and agreed to the published version of the manuscript. This research was funded by the Academy of National Food and Strategic Reserves Administration, grant number JY2303, and Henana Key Laboratory of Grain and oil storage facility & safety, HAUT, Zhengzhou, 450001, China, grant number 2020 KF-A02. Data Availability Statement: Data are available on request from the authors. The data presented in this paper are available for verification by readers. We express our gratitude to the reviewers for their invaluable guidance on this article.