Abstract: The pH, ascorbic, citric and total organic acid content of some local fruits in Nigeria were determined. The mineral content of the fruits, amaranthus vegetable and cowpea (Vigna unguiculata L. Walp) were also determined. Orange juice had the highest level of ascorbic acid but low in citric acid while lime juice is very rich in citric acid. Pine apple juice contained a low level of the organic acids. The effect of the juice from the different fruits on the amaranthus and cowpea composite diets were investigated and correlated with the acids content of the fruits. Orange and grapefruit enhanced Fe and Cu from both amaranthus and cowpea but seem impaired by pine apple and lime juice. All fruit juices enhanced Mg and Zn availability from amaranthus vegetable and cowpea composite diets except that Zn was inhibited by all the fruit juice from cowpea meals. There was generally a strong correlation between ascorbic, citric and total organic acid content of the fruits and the enhancement of mineral availability.