Tropentag, September 16 - 18, 2026, Göttingen "Towards multi-functional agro-ecosystems promoting climate-resilient futures"

Utilisation of agri-food by-products within the water-energy-food nexus in sub-Saharan Africa

¹Eduardo Mondlane University, Fac. of Agronomy and Forestry Engineering, Mozambique
²University of Mohammed VI Polytechnic, College of Agriculture and Environmental Sciences (CAES), Dept. of AgroBioSciences, Morocco
³Zimbabwe Open University, Dept. of Agriculture Management, Zimbabwe

Abstract

Food processing in most African countries is semi-mechanised resulting into generation of abundant agri-food by-products that are frequently underutilised, discarded as waste, burnt or dumped. Examples include pomace, husk, bran, spent grain, oilseed cakes, which retain valuable bioactive compounds such as phenolic compounds, organic matter, minerals, fibres, proteins, functional lipids, and natural pigments. With the increasing awareness of environmental sustainability, resource and food scarcity, agri-food by-products are increasingly being viewed not as waste but as valuable resources for sustainable utilisation. Despite these advances, most of the research on agri-food by-products utilisation have been explored from isolated perspectives such as renewable energy production, soil fertility improvement, wastewater treatment and food or feed development with limited consideration of how these applications interact across interconnected resources systems. As a result, opportunities to maximize resource efficiency, reduce trade-offs and create synergies among water, energy and food systems (WEF nexus) are often overlooked. Therefore, a systematic review was carried out to collect evidence on the multifunctional contributions of agri-food by-products across the Water-Energy-Food (WEF) nexus. A search was conducted in three main data bases, PubMed, Science direct and Scopus as well as in Google Scholar for studies published between 2022 and 2026. The review followed PRISMA 2020 guidelines and 39 eligible studies met the inclusion criteria and were included in the review. The synthesis indicated that the most generated by-products are cereal brans/husks, roots and tuber peels, fruit peels/kernels, oil-seed residues, and brewery extracts that are utilised in bioenergy/ biofuel production, waste water treatment, food ingredients and biofertiliser production. Therefore, instead of focusing on isolated benefits, this review provides a comprehensive synthesis on agri-food by-products utilisation into an integrated Water-Energy-Food (WEF) nexus that reveals patterns synergies and opportunities for sustainable resources management and circular bioeconomy strategies. This is because the Water-Energy-Food (WEF) nexus provides an integrated framework that recognise that water, energy and food systems are highly interdependent, such that decision in one sector influence resources availability, efficiency and sustainability in the other.

Keywords: Agri-food by products, circular economy, functional food ingredients, gender equity, smallholders, sub-Saharan Africa

Contact Address: Reason Charachimwe, Eduardo Mondlane University, Fac. of Agronomy and Forestry Engineering, Maputo, Mozambique, e-mail: reascharagmail.com