Postharvest quality of underutilized African leafy vegetables as influenced by cooking and storage methods: a review

African leafy vegetables (ALVs) are traditional crops with significant nutritional and medicinal value, contributing to food security and improved nutrition, particularly in resource-limited communities. They are rich in vitamins, minerals, antioxidants and bioactive compounds, thus, effective in combating malnutrition and promoting health. Common species such as Cucurbita spp., Vigna unguiculata, Cleome gynandra, Solanum retroflexum, Amaranthus cruentus and Vigna subterranea are well adapted to harsh environmental conditions, enhancing their importance for climate change resilience. However, ALVs remain underutilized due to low market demand, negative consumer perceptions and poor postharvest handling practices. This review synthesizes evidence from peer-reviewed studies examining the effects of cooking and storage methods on nutrient and phytochemical retention in selected underutilized ALVs. Relevant literature was obtained from major scientific databases, including Google Scholar, Scopus, Web of Science and PubMed, using targeted keywords related to ALVs, cooking, storage, nutrients and phytochemicals. Storage conditions assessed included ambient, refrigerated and frozen environments for periods of up to 21 days. Refrigeration was effective in preserving most nutrients during short-term storage, though extended storage led to nutrient degradation. Freezing was more effective in maintaining sensory quality, such as leaf color and texture, and preserving essential nutrients. The review demonstrates that cooking and storage methods significantly influence the nutritional quality of ALVs. Short cooking techniques, including steaming and controlled blanching, enhance mineral bioavailability and retain heat-sensitive nutrients, whereas prolonged boiling causes substantial nutrient losses. The findings highlight the need for improved postharvest practices and policy interventions to promote ALVs in nutrition-sensitive food systems.