Solar drying of banana (“Jazi Kela”) in the rural area of Bhutan: Engineering and product quality aspects

English. Agriculture is the main employment in Bhutan, making it an agriculture-based economy. The project “Solar Food: Reducing post-harvest losses through improved solar drying” is to help indigenous people to preserve their food crops in a more efficient but still natural way by using solar energy for drying. A new idea arose to commercialize food items dried in the solar dryer instead, which would affect not only the income of farmers but the Bhutanese economy and society. The present paper investigates whether an old and a new solar dryer model situated in Bhutan are drying banana slices sufficiently and which model functions more efficient. Experiments on if the maturity of the banana or a pre-treatment affect the drying were done and the nutritional value of the samples was looked at. A focus group discussion helped to understand whether their consumers would like solar-dried food and a market for it exists. Furthermore, an investigation on socio-economic impacts for the commercialization of solar-dried banana in Bhutan was conducted. Outcomes show that the new dryer model in Bhutan dried banana slices sufficiently within 20 hours conducted throughout two days which can be explained by its design. Maturity stages of the banana did not significantly affect drying times. A focus group discussion showed that panelists with a South-East Asian Background are interested in solar-dried bananas and would consume them regularly. The nutritious value was found to change mainly regarding its moisture content before and after drying. A commercialization potentially influences socio-economic aspects. Especially food security would be increased and a steadier availability of healthy foods for the Bhutanese would exist, as well as an additional source of income for farmers develops. The pre-treatment with salt showed a reduced drying time of banana slices, which should be investigated in further research.

English. Imagine using the power of the sun to preserve your food. In Bhutan, where farming is a major occupation, a project called “Solar Food” aims to help farmers do just that. By drying crops with solar energy, food can be stored in a more efficiently and naturally. But there’s more – this idea could also transform these sun-dried foods into profitable products, benefiting not just the farmers, but the Bhutanese economy and society. The present study tested two types of solar dryers in Bhutan to see which one dries banana slices better. It was also explored whether the ripeness of the bananas or a special pre-treatment affects the drying process, and they checked the nutritional value of the dried bananas. Further, locals were asked to see if they could be interested in buying solar-dried bananas. It was found that: • The new solar dryer model was the most effective thanks to its advanced design, drying banana slices sufficiently over two days. • The ripeness of the bananas didn’t create a difference in drying time. • By doing a tasting with people of Southeast-Asian background, they showed a strong interest in solar-dried bananas and said they would eat them regularly. • The nutritional value of the bananas changed mainly in moisture content after drying, which is a normal outcome of the drying process and due to low temperatures in the process. • Commercializing solar-dried bananas could have positive socio-economic impacts, like improving food security, making healthy foods more available year-round, and providing farmers with extra income. • A simple salt pre-treatment reduced the drying time, suggesting an area for further research. This project and a commercialization of solar-dried foods could be a game-changer for Bhutan, providing a natural way to preserve food, boosting the local economy and supporting the well-being of its people.