Rediscovering traditional vegetables to enhance food and environmental sustainability of Sub-Saharan agriculture

Traditional vegetables are valuable but underutilized crops in Sub-Saharan agriculture due to the spread of staple crops (e.g., common bean and common spinach). However, staple crops are highly water demanding and usually require tilling and chemical treatments to grow. Furthermore, they rarely show a balanced equilibrium between macro and micronutrients, thus impoverishing people diet.

This study focused on the evaluation of the impact of no-tillage practices and water scarcity on the nutritional profile of cowpea (Vigna unguiculata L. Walp.) and jute mallow (Corcorhus olitorius L.) edible portions.

After harvesting, cowpea seeds and jute mallow leaves were boiled, dried and grinded.

Cowpea seeds were evaluated for their total starch, proteins and aminoacidic content. Jute mallow leaves were studied for their polyphenolic composition and folates profile.

These species proved to be an extraordinary source of healthy and nutritionally valuable compounds. For instance, HPLC analyses on cowpea seeds showed a relevant amount of aminoacids (4–33.67 mg*g⁻¹), many of which essential (e.g., threonine and tryptophan). Jute mallow leaves revealed a huge variety of polyphenols, among which cryptogenic acid (50–185 μg*g⁻¹), neochlorogenic acid (57–186 μg*g⁻¹) and many quercetin glycosides (99–683 μg*g⁻¹), as shown by mass spectrometry analyses.

Notably, these phytochemicals were not influenced by stress conditions, thus confirming the capability of such species of providing healthy diet also if cultivated under conservative agriculture managements. Therefore, these traditional vegetables are good candidates to promote and couple food and environmental sustainability of Sub-Saharan agroecosystems.