Keywords: days after transplanting, lettuce maturity, mineral content, storage conditions, Nigeria, ANOVA, zinc, potassium, magnesium, iron, sodium, calcium
Influence of maturity and storage conditions on some mineral contents of lettuce
The effects of maturity and storage conditions on mineral contents of lettuce were studied. Samples of lettuce transplanted 50, 60 and 70 days after sowing were collected from an experimental farm in Nigeria. The samples were stored in the laboratory in a polythene bag of 2 mm thickness and in an open shelf and analysed every two days using the AOAC nutritional guidelines. A one–way ANOVA showed significant differences in zinc, potassium, magnesium, and iron contents between fresh lettuce and lettuce stored in polythene bag and open shelf (P ≤ 0.05) but sodium and calcium contents were not significantly different (P > 0.05). There were no significant differences in contents of zinc, sodium, and calcium for the storage periods of 1, 3, 5 and 7 days (P > 0.05) but their magnesium and iron contents were significantly different (P ≤ 0.05). Zinc, calcium and magnesium contents of lettuce 70 days after transplanting were significantly higher than those for 60 and 50 days while the concentrations for the same minerals at 60 days were significantly higher than for 50 days.