Optimization of Infrared Rotary Roasting Conditions for Immature Rice: Effects on Physicochemical and Cooking
Lamul Wiset1, Chainarong Chuayjum2,3, Juckamas Laohavanich1
1Innovative Agriculture Machinery and Post-Harvest Technology Research Cluster, Mahasarakham University, Maha Sarakham 44150, Thailand.
Foods (Basel, Switzerland)
|May 13, 2026
Summary
Infrared (IR) roasting optimizes immature rice processing by adjusting temperature and time. Optimal conditions enhance nutritional value and cooked texture while maintaining desirable qualities.
Area of Science:
- Food Science and Technology
- Agricultural Engineering
- Nutritional Science
Background:
- Immature rice is a popular Asian cereal valued for its color, texture, flavor, and nutrients.
- Processing challenges arise from its fragile structure and pigment sensitivity.
- Developing efficient processing methods is crucial for value-added immature rice production.
Purpose of the Study:
- To investigate the impact of infrared (IR) roasting on immature rice quality.
- To determine optimal IR roasting temperature and time for processing.
- To evaluate the effects on physicochemical, nutritional, and cooked-rice characteristics.
Main Methods:
- Utilized a two-factor, three-level factorial design for IR roasting experiments.
- Employed response surface methodology (RSM) to analyze roasting variables (550-650 °C, 20-40 min).
- Applied multi-response optimization using desirability analysis for condition identification.
Main Results:
- Increased roasting severity reduced yield, moisture, water activity, and chlorophyll.
- Roasting promoted grain darkening, increased phenolic content, and enhanced cooked rice expansion and hardness.
- Optimal conditions (650 °C for 20 min) yielded results closely matching predictions (p > 0.05).
Conclusions:
- IR roasting is an effective green-energy approach for processing immature rice.
- Optimized IR roasting maintains desirable color, nutritional value, and texture.
- This method offers a pathway to producing value-added immature rice products.
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