Recent Advances in Solar Drying Technology for Tomato Fruits: a Comprehensive Review
Abdallah Elshawadfy Elwakeel, Mohsen Gameh, Ahmed Eissa, Mostafa Mostafa
Abstract
The world's most popular and productive vegetable crop is the tomato fruit. The tomato is the second-most important vegetable crop in the world. Fresh tomatoes cannot be stored for a long time because they have a high moisture content (MC). The high MC acts as a suitable environment for the growth of fungi and molds, which leads to damage to stored tomatoes. So, MC must be decreased to a suitable level for storage and handling using a suitable drying method to maintain nutritional value and natural color properties. There are many drying methods that can be used for drying tomatoes. Throughout history, tomato drying methods have relied on direct sunlight, firewood, fossil fuels, and coal, leading to carbon emissions. These techniques are costly, unreliable, and unsanitary. There are now many modern methods, including solar drying, microwave drying, vacuum drying, infrared drying, freeze drying, oven drying, and various hybrid drying techniques. But hot air drying, solar drying (SD), sun tunnel drying (STD), microwave drying (MD), and freeze-drying (FD) are some of the popular methods of drying tomatoes for preservation. This paper aims to present the state-of-the-art solar energy technologies for tomato drying.