Impact of Heat Treatment on Vitamin C Content in Native Leafy Vegetables of Uyo, Nigeria

Abstract

Background: The native vegetables of Uyo, Nigeria, valued for aroma and taste, are often consumed without knowledge of nutritional content. This study evaluated vitamin C levels in ten leafy vegetables before and after boiling, highlighting their role in nutrition, disease prevention, and reducing mortality from infectious diseases. Methods: Vitamin C concentrations were analyzed using UV spectrophotometry. Results: Among the vegetables analyzed, Afang (Gnetum africanum) had the highest vitamin C levels across treatments: raw (2,066.95 μM/ 30 g), boiled at 60 °C (1,492.14 μM/30 g), and boiled at 80 °C (1,110.44 μM/30 g), emphasizing its nutritional value. Conversely, the lowest concentrations were found in Atama (215.27 μM/30 g raw), Waterleaf (285.70 μM/30 g at 60 °C), and Bitter leaf (182.33 μM/30 g at 80 °C). Conclusion: The study confirmed vitamin C presence in all the vegetables studied, showing varied responses to boiling, with both reductions and occasional increases under moderate heat. Most vegetables exhibited net vitamin C loss. Findings suggest unique release patterns and build on prior research on heat effects on vitamin A in these vegetables.