Solar drying of leafy vegetables has gained significant attention in recent years among farmers as a lucrative and effective technique for preserving leafy vegetables. Fresh leafy vegetables are known for their high nutrient content in terms of vitamins, minerals, and fiber, and therefore a great addition to people’s daily diet with numerous health benefits. Urban and rural dwellers in Kenya consume about 147 and 73 kg of fresh vegetables per Capita per year, respectively (Onim and Mwaniki 2008).
However, vegetables’ short life span poses a great challenge for producers, retailers, and consumers who want to maintain their freshness and nutritional value. Preserving the freshness and nutritional value of leafy vegetables such as kale, spinach, and sukumawiki is problematic due to their high moisture content. Therefore knowledge of the factors affecting their perishability is very important to reduce food losses.
As a matter of fact, most farmers produce vegetables during the rainy season, and they fetch a low price when sorted during peak harvest times. Moreover, some leafy vegetables are discarded due to excess supply in the market during rainy seasons. For this reason, farmers have started to solar dry their leafy vegetables to reduce wastage during peak seasons and store them until off-peak dry season when production is low and are price is high. This allow all-year-round supply of leafy vegetables.
What is solar drying?
Solar drying food according to Food and Agriculture Organization (FAO), is a method of drying agricultural produce using solar energy. It is the use of the sun’s heat to remove moisture from farm produce to preserve their quality and increase their shelf life.
How to prepare the leafy vegetables for solar drying.
Harvesting.
Harvest mature lower green leaves carefully.
Sorting.
Discard all yellow leaves, distorted, and pests affected. Wash your hands thoroughly with detergent before sorting. Start by removing the stalk from the leaves and cut the leaves into small sizes for fasf, and even drying.
Washing.
Wash the leaves thoroughly in clean water. Dissolve some salt in lukewarm water. Add the leaves in salty water and stir them thoroughly. Transfer the leaves to cold water, and drain the excess water.
Loading on trays
Spread the leaves well on the trays and place them on the solar dryer. Uniformly spread the leaves in the trays to avoid the chances of mold formation. Arrange the leaves in a single layer on drying trays. This will favor good air circulation within the dryer.
How to operate the solar dryer.
For better results, ensure the solar drier faces the sunlight directly, and the flow of air is good.
Coverer the with transparent materials or glass for sunlight to pass through while trapping the heat inside. Additionally, transparent plastics are another ideal material for solar driers.
Monitoring the drier.
In order to get good results, regularly check on the leafy vegetables drying progress. It takes about 2 to 3 days for the leafy vegetables such as kale, and spinach to completely dry. Dry leaves are brittle and crumble easily.
Storing.
Allows the dry leaves to cool down. Pack the dried leaves in plastic bags, and seal them tightly. Transfer the bags into an air tight clean containers for additional protection. Properly store them in a cool dry room.
Dried vegetables can be stored in such conditions for more than six months. These vegetables are available to the consumer even though they’re out of season. Furthermore, farmers who dry their vegetables can enjoy good prices.
Types of solar dries used for drying leafy vegetables.
Direct mode of drying leafy vegetables:
Direct mode of drying is the simplest method that uses solar energy from the sun to directly heat the chambers. This is the method is used by farmers in hot regions. In this method, leafy vegetables are exposed directly to the sunlight.
Indirect mode of solar drying leafy vegetables.
Farmers in areas with limited sunlight, and changing weather conditions, an indirect mode of drying can be employed. This is the mode where heat exchangers absorb heat energy, and transfer this solar heat to the drying chambers. This ensures constant airflow, and temperatures during the drying process.
Mixed mode of leafy vegetable solar drying.
This mode of solar dying uses both elements of direct and indirect modes of drying. This mixed hybrid increases the overall performance of the drying process. For example, mixed mode combines the traits of direct and indirect mode to enable continuous drying during fluctuating weather conditions
There are several Benefits associated with solar drying leafy vegetables.
First and foremost solar drying reduces food wastage. As discussed above, leafy vegetables are produced in large quantities during the rainy season. This leads to excess supply in the market which in turn leads to decreasing in price. Some of the leafy vegetables end up in pits and garbage. Solar drying has emerged as an alternative way of mitigating this problem of food wastage.
Secondly, solar drying is cost-effective as it relies on natural light from the sun to provide energy to dry the leafy vegetables. This reduces operating costs such as fuel or electricity bills.
Is an environmentally sustainable method. Furthermore, Solar drying does not produce harmful gasses to the ozone layer as compared to conventional methods
Solar drying preserves leafy vegetables’ proper storage. Solar dying preserves leafy vegetables in terms of nutrients, colour, and essential oil, for proper storage.
More hygienic. Compared to traditional open-air sun drying solar drying is more hygienic.
Protect the drying leafy vegetables from pests’ damage. Solar drying shields leafy vegetables from dust, insects, humans, birds, roaming pests, and microbial contamination.
Increase farmer earnings. Solar drying improves farmers’ income, food safety, food security, and food availability.
Conclusion.
In conclusion, solar drying leafy vegetables is an effective way to preserve their freshness and nutritional value for a prolonged period of times of up to six months. In the final analysis, solar drying of leafy vegetables such as kale, and spinach guarantees long long-lasting and sustainable approach to preserving leafy vegetables.
