EFFECT OF PROCESSING ON THE MINERAL ELEMENTS AND ANTINUTRIENTS OF SOME EDIBLE VEGETABLES FROM KEFFI, NASARAWA STATE, NIGERIA

This study investigated the effect of boiling, steaming and sun drying on the mineral elements and anti-nutrients of six varieties of edible vegetables: Ewedu (Corchorusolitorius), water leaf (Talinum triangulare), sand sagebrush (Arternesia spp), pumpkin leaf (Telfairia occidentalis), bitter leaf (Vernonia amygdalina) and spinach (Spinaciaoleracea). The mineral elements and anti-nutrients were determined using standard analytical methods. Sodium, zinc, copper, magnesium, phosphorus and iron were among minerals present with phosphorus as the most dominant of these minerals obtained with values ranging from 31.31 mg/100 g in boiled water leaf to 225.90mg/100 g in sundried pumpkin leaf. Anti-nutrients such as saponin was obtained with values ranging from 2.14 –3.06% (in water leaf), 0.72 – 2.82% (in ewedu), 2.18 – 2.72% (in sand sagebrush), 2.10 – 2.68% (in spinach), 0.12– 2.15% (in bitter leaf) and 0.08 - 0.20% (in pumpkin leaf). Processing methods showed deviation in minerals of 235.00% (phosphorus) in boiled water leaf to 0.09% in sun dried pumpkin leaf and anti-nutrients from the raw leaves. The deviation was observed more on anti-nutrients like oxalate, phytate, alkaloids and cyanide. For minerals, the deviation was more on the amount of phosphorus and magnesium after boiling and steaming. Sun drying was insignificant. Processing reduces the mineral content of the vegetables, but makes them bioavailable by removing the anti-nutrients to the barest minimum.