Mineral Composition of Cassava Leaves (Manihot esculenta Crantz) Harvested at Various Periods and Growth Stages, and Its Changes during In Vitro Simulated Gastrointestinal Digestion

Abstract

Total and bioaccessible minerals in edible cassava (Manihot esculenta) leaves (ECLs) harvested at different maturity stages and seasons were assessed by microwave plasma atomic emission spectroscopy. The results showed significant (p < 0.05) variations at maturity stages across seasons. A two-way analysis also showed significant effects of the variety and period of harvest. However, the highest content of total minerals was obtained at 6 months after planting (MAP), except for Mn, Zn, and Cu. The total macromineral contents (mg/100 g) were K (64.14–3532.94), Ca (34.19–543.57), Mg (25.84–365.03), and Na (73.84–727.70), and micromineral contents (μg/100 g) were Mn (779.98–7550.89), Zn (55.47–997.70), Cu (31.76–7288.18), and Fe (8.57–30.85 mg/100 g). The bioaccessibilities of minerals were Fe (0.56–63.85%), Mn (0.49–63.64%), and Zn (1.77–60.82%), while bioaccessibilities of Ca (0.22–48.30%) and Na (1.53–46.80%) were low. Besides, the bioaccessibility of minerals at 6MAP was lower than that in advanced stages of maturity. The variety TMS 96/1414 showed the highest bioaccessible minerals (Mn 93.35 μg/100 g and Cu 53.01 μg/100 g) at 9MAP, while IRAD4115 presented the highest bioaccessible minerals (Fe 7.79 μg/100 g and Zn 133.64 μg/100 g) at 9MAP and 12MAP, respectively. A significant (p < 0.01) positive correlation was found between the total and bioaccessible mineral contents. The study reveals that minerals in ECLs harvested at different stages were bioaccessible, with high values at mature stages, which can be recommended as mineral sources for consumers.