Enhanced Quick-Cooking Red Beans: An Energy-Efficient Drying Method with Hot Air and Stepwise Microwave Techniques

Area of Science:

• Food Science and Technology
• Agricultural Engineering
• Process Optimization

Background:

• Traditional drying methods for legumes can be energy-intensive and time-consuming.
• Developing energy-efficient processing techniques is crucial for sustainable food production.
• Quick-cooking beans offer convenience but require optimized drying to maintain quality.

Purpose of the Study:

• To introduce and optimize an energy-efficient drying method for producing quick-cooking red beans.
• To investigate the effects of hot-air and stepwise microwave heating on drying parameters.
• To determine optimal conditions for maximizing effective diffusivity and minimizing energy consumption.

Main Methods:

• Combined hot-air drying with stepwise microwave heating.
• Response surface methodology (RSM) for parameter optimization.
• Evaluation of step-up and step-down microwave heating modes.
• Analysis of effective diffusivity coefficient (De) and specific energy consumption (SEC).

Main Results:

• Optimal conditions identified: 90 °C hot air, 450 W microwave power, 0.2 Hz rotation.
• De ranged from 0.53 × 10⁻⁹ to 3.18 × 10⁻⁹ m²·s⁻¹; SEC ranged from 16.58 to 68.06 MJ·(kg·h⁻¹).
• Step-down microwave heating (450 W-to-150 W or 300 W-to-150 W) proved most effective for energy saving.

Conclusions:

• Hot-air drying combined with step-down microwave heating is a promising energy-saving technique for quick-cooking beans.
• The optimized method preserves rehydration qualities and texture comparable to traditional methods.
• This approach offers a sustainable solution for efficient legume processing.