Assessment of mineral and sugar contents of Plectranthus edulis landraces

ABSTRACT The Ethiopian potato [Plectranthus edulis (Vatke) Agnew] is an annual root tuber that is underutilized due to a lack of knowledge about its nutritional value. The plant is known by its local landrace names. Investigating the relatedness, and variation in nutrient composition, among P. edulis landraces is important for selecting the best genotype for breeding. The study was undertaken to examine mineral nutrients and sugars in 5 P. edulis landraces collected from southern Ethiopia. Samples were analyzed for Ca, Mg, Fe, Zn, Cu, Mn, Co, Cr Ni, Cd, Pb, and fructose, glucose, sucrose, and maltose using Inductively Coupled Plasma-Optical Emission Spectrometry and a High-Performance Liquid Chromatography-Refractive Index Detector, respectively. The P. edulis tubers accumulate large levels of macro- and micro-elements. The Mg and Ca were the most abundant macro-nutrients. The Tseka landrace had the highest Mg content. Iron was the most abundant micro-nutrient in P. edulis tubers. There were no Co, Cd, and Pb detected in P. edulis tuber landraces. All P. edulis landraces contained glucose (15.1–21.1 g/100 g) and fructose (3.34–4.10 g/100 g); sucrose and maltose were not detected. Quantities of all parameters were affected by landraces and their concentrations were different. The unnuko landrace had a lower total sugar level than the other 4 types, making it a good choice for diabetics. The P. edulis landraces can provide minerals and sugar for the human diet. Diversity in nutrient content within landraces could be an opportunity to generate improved hybrids.