Smallholder farmers in Uganda and Kenya produce a variety of fruits, traditional and exotic vegetables, spices, and herbs that have unique nutritional, nutraceutical and functional properties. However, the value derived from these crops is limited due to postharvest losses, seasonal production, limited value addition and market access problems. Developing and applying affordable food preservation technologies could reduce postharvest losses by up to 68%. Additionally, food preservation by drying not only prolongs shelf life, but it also minimizes storage, transportation and packaging costs.

About the project

In 2017, Makerere University through the Department Agricultural and Biosystems Engineering at the College of Agricultural and Environmental Sciences (CAES) received funding under the BioInnovate Africa Programme Phase II to implement a project titled; “Adaptation and Promotion of Refractance Window Drying Technology (RWDT) for Production of High Quality Bio-products”. The RWDT uses heat to dry fruits and vegetables, while maintaining the nutritive qualities. With RWDT, liquid foods, purees or slices are dried on one side of a thin plastic film, whose other side is in close contact with hot water at temperatures below boiling point. The plastic film, usually in the form of a conveyer, is susceptible to infrared radiation, therefore allowing thermal energy to be transferred from the water to the food. Transmission of infrared radiation stops when the food is dry, and the product scraped off the conveyor. The temperature of the product remains relatively low during drying, resulting in better quality retention due to reduced moisture content and inhibited microbial growth. The heated water is recycled, further improving thermal efficiency of the system.

The Project Leader, Prof. John Muyonga disseminating the research findings and outputs

Project duration and objectives

The three-year project worth 750,000 USD had been scheduled to end in December 2020 but was extended to June 2021 due to the outbreak of COVID19 and the subsequent restrictions aimed at curbing the spread of the pandemic. The development objective of the project was to create new business opportunities in food value addition and agro-processing equipment fabrication. The project specifically aimed to develop a heat drying technology that is affordable yet yields high quality products, even from heat sensitive materials. It also aimed to; support local fabricators to make quality Refractance Window Drying equipment suitable for use by local agro-processors; improve the quality of products, mainly fruits, vegetables and herbs on the Ugandan & Kenyan markets; minimize post-harvest losses; increase the use of locally produced food ingredients derived from fruits, vegetables and herbs; and to enhance collaboration among farmers, agro-processors, researchers and support agencies.


Project activities

 Working with various partners namely; Jomo Kenyatta University of Agriculture and Technology, Kenya Industrial Research and Development Institute (KIRDI), TONNET Agro-engineering Company Limited, East Africa Nutraceuticals Ltd (EAN), Food and Nutrition Solutions Ltd (FONUS) and the Ministry of Trade, Industry and Cooperatives, Uganda, Makerere University implemented several activities under the project. These included designing and fabrication of low cost dryers, techo-economic evaluation of the dryers, evaluation of the refractance window dried products, assessment of the capacity of agro-processors and fabricators; training of farmers, agro-processors, and fabricators; and training of graduate students.


Project closure workshop

On 22nd March 2022, the research team led by Prof. John Muyonga held the project closure meeting at which they disseminated the findings and outputs. The meeting heeld in the School of Food Technology, Nutrition and Bio-Engineering Conference Hall was graced by the Vice Chancellor, Prof. Barnabas Nawangwe, the Principal CAES, Dr Gorettie N. Nabanoga, the Programme Manager of Bio-Innovate Africa Programmes, Dr Julius Ecuru, and representatives of partner institutions.

The Hybrid Refractance Window Drying Technology (RWDT) Developed by BioInnovate Project Team

Achievements registered under the project

Disseminating the research findings, Prof. Muyonga noted that the project had registered significant achievements.

Guided by Prof. Muyonga, the project members including; Dr Julia Kigozi (Lecturer – Department of Agricultural and Biosystems Engineering, Makerere University) Dr. Peter Tumutegyereize (Department of Agricultural and Biosystems Engineering, Makerere University), Mr Shaffic Ssenyimba and Mr Raymond Mutumba (both MSc Students at Makerere University), and the TONNET Agro-engineering Company Limited team designed and fabricated several low cost refractance window drying machines. Additionally, the project team optimised the refractance window drying conditions for different products including passion fruit juice, pineapples, mango puree, jackfruit puree and cowpea leaves. They also developed protocols and guidelines for use of refractance window dried fruits as ingredients in foods. Using the RWD technology, the research team has produced a number of marketable products including – dried fruit slices, dices and strips; fruit powders; bread and cake containing refractance window dried fruits; as well as fruit gummies. The team is in the process of evaluating results for refractance window and solar dried pineapple slices. The team is also evaluating results for drinks produced from mixing refractance window dried pineapple powder in water, the different yoghurts, cookies and porridge made with different proportions of refractance window dried jackfruits, and breakfast cereal containing different proportions of refractance dried pineapple.

Some of the products produced using the refractance window drying technology

Other achievements registered under the project included; obtaining a Certificate of Grant of Utility Model from the Uganda Registration Services Bureau patenting the Electric and Biomass Powered Refractance Window Drying Apparatus invented by the research team; training of farmers in the use of Refractance Window Drying Technology and the use of RWD products as ingredients, training of 16 fabricators, training of 6 graduate students (2 PhD & 4 M.Sc.), refurbishment of facilities at Makerere University Agricultural Research Institute Kabanyolo (MUARIK); and publication of 12 articles in internationally recognized journals. Articles published included; (1) Adoption of the Refractance Window Drying Technology in the Drying of Fruits and Vegetables in Uganda Journal of Advances in Food Science & Technology, 1-10; (2) Design and Evaluation of a Refractance Window Lab-scale Dryer Journal of Engineering, Design and Technology;  (3) Techno-Economic Analysis of a Refractance Window Dryer Prototype Developed by Kenya Industrial Research and Development Institute Current Journal of Applied Science and Technology; (4) Drying Behaviour and Optimization of Drying Conditions of Pineapple Puree and Slices using Refractance Window Drying TechnologyJournal of Food Science and Technology, 1-10; (5) Optimization of Refractance Window Drying Conditions for Passion Fruit Puree; (6) Optimization of Drying Conditions for Jackfruit Pulp using Refractance Window Drying technologyFood Science & Nutrition; (7) Performance Analysis of An Arduino Based Calibration and Temperature Control System for a Refractance Window Dryer; (8) Arduino based control of the Food and Water Conveyance Systems of a Refractance Window Dryer; (9) Techno Economic Analysis of Refractance Window Drying of Fruits: A Case of Small-Medium Scale Agro Processors in Uganda; (10) Physicochemical Properties, Sensory Acceptance and Storage Stability of Yogurt Flavoured with Refractance Window Dried Passion Fruit Powder – Asian Food Science Journal, 38-49; and (11) Exploring the Potential of Jackfruit (Artocarpus heterophyllus Lam), (2021) – Asian Food Science Journal. Page 97-117.

According to Prof. Muyonga, plans are underway to develop a Memorandum of Understanding between Makerere University and a private firm to oversee the utilisation of Refractance Window Drying equipment at MUARIK for commercial production of value added foods. “There are also plans to facilitate three agro-machinery companies – 2 in Uganda and 1 in Kenya to produce Refractance Window Dryers under the guidance of Makerere University and Kenya Industrial Research and Development Institute (KIRDI). We also hope to engage development agencies to support farmer groups to procure Refractance Window Dryers,” he noted while explaining the research team’s commercialization arrangements.

Explaining the design process of the Refractance Window Dryer, Dr Julia Kigozi said the technology is mechanically simple, cheaper to purchase, energy efficient with high drying speed and low operational costs, and ensures retention of product quality. Dr Kigozi revealed that the steps were being taken to promote the use of RWD technologies through Jazi Agro-processing Solutions Limited. Jazi Agro-processing Solutions Limited is a private company that specializes in food processing and doubles as a consultancy in regards to agro-processing solutions with a goal of promoting the agro-processing sector in Uganda. The company carries out training and mentoring on fundamentals necessary for the operation of agro-processing industries.

Dr. Julia Kigozi explaining the design process.

During the meeting, Mr. Raymond Mutumba shared the outreach and dissemination programmes conducted by Food and Nutrition Solution Ltd (FONUS) with regard to the Refractance Window Drying Technology. Based at the School of Food Technology, Nutrition and Bio-Engineering, Makerere University, FONUS provides consultancy services in the fields of food value addition, community nutrition, food handling and hygiene, post-harvest handling of foodstuffs, facilitation of farmer group learning processes and project evaluations. The main purpose of FONUS’ engagement with the project was to promote uptake of the RWD technologies among end users. This was done through a series of engagements with farmer groups, small and medium agro-processors, and processors that utilise the RWD products and ingredients in foods.

Community engagements undertaken by FONUS included a situational analysis on the potential utilization of the Refractory Window Drier Technology in food value addition, training agro-processors in the use of hybrid RWD, and training of medium and large scale agro-processors in the use of RWDT in the drying of fruits and vegetables. In addition, FONUS conducted trainings on the use of RWDT products and ingredients and flavours in foods, and assessed the marketability of RWDT products.

According to Mr. Mutumba, the community engagements revealed that the RWDT presented a viable solution for preservation of fruits and vegetables in Uganda. The engagements also revealed that the incubatees were more willing to adopt the technology compared to already established processors. It was also discovered that more research needs to be done in RWDT energy efficiency if the RWDT products are to have competitive process on the market. The team called for government support to increase uptake of the technology, noting that individuals and small processor groups may not easily afford it.

Addressing participants, the Vice Chancellor, Prof. Barnabas Nawangwe appreciated SIDA for the enormous support extended towards research and training programmes at Makerere University. “The University has reached the 1,000 mark of staff with PhDs, and almost half of these have been trained under SIDA,” he noted.  In addition to other research programmes, SIDA supports the BioInnovate Africa Programme. The Vice Chancellor applauded the Department of Agricultural and Biosystems Engineering at CAES for the commendable initiative aimed at improving the quality and increasing shelf life of agricultural products in Uganda. “The products produced out of this initiative can be major exports for Uganda. We need to move towards commercializing our products. We however need to improve our marketing skills,” he explained while cautioning the research team on the importance of marketing the products. He also advised researchers to make use of the Intellectual Property Management Office at the University to patent their products.

The Vice Chancellor, Makerere University, Prof. Barnabas Nawangwe addressing participants

Commenting on the significance of agriculture in the development of the economy, the Vice Chancellor said the CAES has a great role to play in improving the sector. Appreciating the research output at CAES, he called on the College to take lead in the establishment of a central business incubation unit to promote research and innovation at Makerere.

In line with 2020-2030 Strategic Plan that aims to transform Makerere into a research-led University, the Vice Chancellor said it was time to do things differently. “At the moment, Makerere is a research-intensive not research-led University. We have excelled in research publications. We need to move towards churning out companies if we are to make positive impact on our economy. You can remain top on research while churning out companies,” he explained, sharing an example of the University of Istanbul that churns out 300 companies per year worth about three billion USD, and is greatly contributing to the development of the country’s economy. The Vice Chancellor echoed the need for Makerere University to make contribution towards the Parish Development Model. “We will be judged harshly if we do not do anything to liberate our people,” he said.

In her remarks, the Principal of CAES, Dr Gorettie N. Nabanoga appreciated SIDA and BioInnovate Africa for the support extended towards the research project. She applauded the School of Food Technology, Nutrition and Bio-Engineering for always writing successful projects. “Despite the small number of staff at the School, they feature prominently in resource mobilization,” she said. She commended the project implementation team for the significant outputs and strong partnerships. “The project has all that is required to be considered successful and is key to obtaining practical solutions for the agricultural sector,” she explained, noting that CAES is academically productive due to the tireless efforts of staff in different units. Commending the quality of the research outputs, Dr Nabanoga said the project would significantly address the current market needs.

The Principal of CAES, Dr Gorettie N. Nabanoga delivers her remarks at the workshop.

Like the Principal, the Dean, School of Food Technology, Nutrition and Bio-Engineering, Dr Abel Atukwase appreciated BioInnovate Africa for the support extended to the project. He expressed gratitude to the Vice Chancellor for his unwavering supports towards programmes at CAES and the University in general. He congratulated the project team upon the worthwhile initiative.

Dr Abel Atukwase, Dean School of Food Technology, Nutrition and Bio-Engineering (SFTNB), CAES speaking at the workshop.

The Head, Department of Agricultural and Biosystems Engineering, Makerere University, Dr. Ivan Muzira Mukisa, acknowledged the efforts of Prof. Muyonga in promoting research and innovation at the College and University in general. “The success we continue to register is largely due to the commitment of staff. Prof. Muyonga has been a key pillar in research, teaching and mentorship of students,” he said. Highlighting the different research initiatives, including the Food Technology and Business Incubation Centre as well as FONUS, Dr Mukisa said the School had greatly provided opportunities for the processors to improve their skills.

The Head, Department of Agricultural and Biosystems Engineering (DABE), Makerere University, Dr. Ivan Muzira Mukisa, acknowledged the efforts of Prof. Muyonga in promoting research and innovation at the University.

Delivering a presentation on government-academia-private sector partnership in technology development and promotion, the Representative of the Commissioner of Small and Medium Enterprises at the Ministry of Trade, Industry and Cooperatives, Dr Steven Mbogo Kiya thanked the sponsors of the project, as well as the partnering academic institutions for the efforts towards advancing agricultural technologies. He called for continued training of the youth and women in the utilization of new technology to boost the quality of agricultural products in the country.

The Programme Manager, BioInnovate Africa, Dr Julius Ecuru acknowledged the great work done by the research team, saying the project demonstrated that it is possible for academia, industry and government to work together to move ideas to the market. He commended Makerere University for winning 8 out of the 20 projects supported under BioInnovate Africa Programme Phase II. He pledged continued support for scientists in the region.

The workshop was moderated by Dr Gaston Ampe Tumuhimbise from the School of Food Technology, Nutrition and Bio-Engineering, CAES.

Dr. Gaston Ampe Tumuhimbise, Senior Lecture, Department of Food Technology & Nutrition, Makerere University, Managing Director FONUS and Country Director, African Institute for Capacity Development (AICAD), moderated the meeting.

About BioInnovate Africa

BioInnovate Africa is a regional innovation-driven initiative stimulating a bio-economy in eastern Africa. The initiative is supported by the Swedish International Development Cooperation Agency (Sida), and implemented by International Centre of Insect Physiology and Ecology (icipe). The initiative supports multidisciplinary teams of scientists, researchers, and innovators to co-develop and pilot innovative and economically viable bio-based ideas, interventions, and technologies. BioInnovate Africa offers grants for innovative bio-based research ideas and technologies with prospects for business and the market. While funding bio-based innovation projects remains the core activity of BioInnovate Africa, the initiative’s strategy now includes developing a knowledge-based bioeconomy in eastern Africa. This is built on the premise that collaboration at the national and regional level, and between researchers and private sector partners, is the surest way to translate scientific outputs into usable, and commercially scalable products and technologies. Current BioInnovate Africa partner countries are: Burundi, Ethiopia, Kenya, Rwanda, Tanzania and Uganda.

Please see Downloads below for presentations from the BioInnovate Closure Workshop

FONUS presentation_ Bioinnovate closure meeting 22.3.22

Dr. Julia_RWD – Design process

Bioninovate presentation by MTIC 22.03.22

Prof-Muyonga-Overview BioInnovate


Bioninovate presentation by MTIC 22.03.22


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