# Process optimization of microwave drying for rice based on response surface methodology

## TL;DR

This study optimizes microwave drying of rice to improve its nutritional quality using statistical methods.

## Contribution

A novel multi-index optimization model using response surface methodology to enhance rice drying quality.

## Key findings

- Optimal parameters for rice drying include 52.47°C hot air temperature, 20 kW microwave power, and 2.78 cm grain layer thickness.
- The predicted nutritional values matched closely with experimental results, with relative errors below 3%.
- Visual process charts were developed to guide practical adjustments in rice drying processes.

## Abstract

To optimize the microwave drying process of paddy rice and improve its quality, the effects of hot air temperature, microwave power, and grain layer thickness on the post-drying potassium content, calcium content, vitamin B₁ content, and free fatty acid content of rice were investigated. Using response surface methodology, an experimental scheme based on the Box-Behnken design was constructed to analyze the influence of these three factors on the four nutritional and biochemical indicators. A multi-index optimization model was established and validated. The results showed that all response indicator models were statistically significant. The optimal process parameters were determined as follows: hot air temperature of 52.47°C, microwave power of 20 kW, and grain layer thickness of 2.78 cm. The corresponding predicted values were potassium content of 3724 mg/kg, calcium content of 113.7 mg/kg, vitamin B₁ content of 0.290 mg/100g, and free fatty acid content of 21.5 mg/100g. Validation experiments demonstrated that the dried rice under these conditions exhibited excellent quality, with relative errors between predicted and measured values below 3%, indicating the reliability of the model and the significant improvement in rice drying quality achieved by the optimized process. Furthermore, visual process reference charts were developed to provide a theoretical basis for adjusting process parameters in practical production.