Comparative evaluation of mineral elements and water-soluble vitamins present in leaves of purple-red skin potato (Ipomea batatas) and Nigerian spinach (Celosia argentea)

Abstract

Sweet potato leaves are a valuable source of essential micronutrients and have the potential to play a significant role in improving dietary diversity, particularly in addressing micronutrient deficiencies in Nigeria. This study compared the nutrient content of the leaves of purple-red skin sweet potato (Ipomoea batatas) and Nigerian spinach (Celosia argentea). Purple-red skin sweet potato leaves were sourced from a farm at Olubadan Estate, while Nigerian spinach leaves were purchased from Molete Market, both in Ibadan, Oyo State, Nigeria. The concentrations of phosphorus, iron, zinc, and calcium were determined using a spectrophotometric method, while potassium and sodium were analyzed using flame photometry. The results showed that concentrations of potassium (357.99±1.15 mg), sodium (7.83±7.83 mg), and zinc (1.69±0.03 mg) in sweet potato leaves were significantly higher (p<0.05) than those observed for Nigerian spinach: potassium (346.59±4.73 mg), sodium (7.04±7.04 mg), and zinc (1.33±0.01 mg). The results also showed that Vitamin A (2.13±.00 µg/100g), Vitamin C (2.69±.02 mg/100g), and Vitamin B9 (0.31±.02 mg/100g) content of sweet potato leaves were significantly higher (p<0.05) than that of Nigerian spinach. However, there was no significant difference (p>0.05) in the phosphorus content of both leaf samples. In conclusion, the findings showed that sweet potato leaves had higher micronutrient composition compared to Nigerian spinach. Promoting consumption of sweet potato leaf alongside the commonly consumed Nigerian spinach could enhance dietary diversity, improve public health, and help address micronutrient deficiencies, particularly in limited-resource communities in Nigeria.