Introduction
Dehydration is a method of food preservation that removes moisture from vegetables like tomatoes and onions, extending their shelf life and reducing weight for easier storage and transport. The process involves drying the vegetables using methods such as sun drying, air drying, or mechanical drying (e.g., hot air, freeze drying).
Tomato Dehydration: Tomatoes are sliced or pureed and dried at moderate temperatures (50–70°C) to retain color and flavor. Common products include dried tomato slices, powders, and flakes.Onion Dehydration: Onions are peeled, sliced, and dried at around 50–60°C. The final product includes onion flakes, granules, or powder, commonly used in seasonings and processed foods.Dehydration helps preserve the natural taste and nutrients while preventing microbial growth.
Solar drayer
Solar dryers are devices that use solar energy to remove moisture from food products. They are more efficient than traditional sun drying as they protect food from dust, insects, and contamination.
The main types of solar dryers include:
1. Direct Solar Dryer:Food is exposed to sunlight inside an enclosed chamber with a transparent cover.Heat builds up inside, accelerating the drying process.Example: Box-type solar dryer.
2. Indirect Solar Dryer:Sunlight heats the air in a separate solar collector, and the warm air is circulated into the drying chamber.Prevents direct exposure to sunlight, preserving color and nutrients.Example: Cabinet solar dryer.
3. Mixed-Mode Solar Dryer:Combines direct and indirect drying.Sunlight heats both the drying chamber and the air, increasing efficiency.
4. Hybrid Solar Dryer:Uses solar energy along with an auxiliary heat source (electric or biomass) for drying even when sunlight is low.Suitable for commercial drying operations.
Each type is chosen based on climate conditions, the type of product, and the drying efficiency required.
Dome Solar Dryer
A Dome Solar Dryer is a type of solar drying system designed with a dome-shaped structure that efficiently traps solar heat, providing uniform drying conditions for various agricultural products like fruits, vegetables, spices, and herbs.
Features & Working Principle Dome-Shaped Structure: Maximizes sunlight absorption and enhances airflow. Transparent Cover: Usually made of polycarbonate or UV-stabilized plastic, allowing sunlight to penetrate while preventing heat loss. Ventilation System: Ensures proper air circulation to remove moisture efficiently.Solar Energy Utilization: Uses direct solar radiation to heat the air inside the dome, accelerating the drying process.
