Overview
Mode and colleagues ripened mature green banana, mango and plantain from one market source in Sokoto, Nigeria, either naturally or with technical calcium carbide at 10 or 30 g per kg of fruit, then measured proximate composition, phytochemicals, antioxidant capacity, minerals and arsenic, cadmium and lead. Metals were determined by AAS after nitric/perchloric digestion of homogenised fruit, in triplicate, with five fruits per group. Table 3 reports means ± SD in mg/kg together with the composition of the carbide itself.
Key numbers
- Plantain total arsenic: 1.640 ± 0.364 mg/kg naturally ripened, 5.930 ± 1.176 with 10 g/kg and 9.940 ± 2.436 mg/kg with 30 g/kg carbide (Table 3, p. 12).
- Plantain lead: 0.052 ± 0.021 (control), 0.143 ± 0.038 and 0.183 ± 0.011 mg/kg; cadmium 0.001–0.003 mg/kg (Table 3).
- The calcium carbide used contained arsenic 21.75, cadmium 0.052 and lead 0.881 mg/kg (Table 3).
Methods (brief)
HNO3/HClO4 wet digestion of 0.5 mL homogenate; AAS (PerkinElmer PinAAcle 900H). No detection limit, reference material or recovery is reported for arsenic, cadmium or lead, and the arsenic technique (for example hydride generation) is not described.
Evidence Fitness
A controlled within-study comparison of ripening treatments on fruit from one bunch. Absolute arsenic levels are far above other plantain data, so the size of the levels is uncertain even though the increase with carbide is reported as significant. The plantain control lead is printed identically to the mango control lead (0.052 ± 0.021), so a copying error cannot be excluded. Whether metals were measured on peeled pulp or whole fruit is not stated.