Effect of Cultivar and Time of Harvesting on the Nutritional and Phytochemical Composition of Jute Mallow (Corchorus olitorius) Leaves

To maximize the huge nutritional benefits of the tender and newly formed leaves of Jute mallow (Corchorus olitorius) at the flowering and fruiting stages (10-12 weeks after planting [WAP]), the tender leaves of two Corchorus cultivars (Co-Ekiti and Co-Lagos) were harvested at 4, 10, and 12 WAP. The harvested tender leaves were oven-dried and analyzed for their proximate, minerals, and phytochemicals. Crude protein was in the range of 20.76% to 23.22%, crude fiber 6.50% to 7.65%, ash 10.03% to 12.77%, crude fat 4.79% to 5.25%, carbohydrate 40.537% to 49.99%, and moisture 13.03% to 13.46%. The crude protein, fiber, and some of the minerals were higher at 10 and 12 WAP. Potassium (K) was in the range of 1103.5 to 1285.5 (mg/100 g), manganese (Mn) 11.66 to 13.58 (mg/100 g), zinc (Zn) 5.11 to 17.16 (mg/100 g), iron (Fe) 17.33 to 27.67 (mg/100 g), and magnesium (Mg) 363.40 to 392.48 (mg/100 g). Magnesium, zinc, copper, and phosphorus in the tender Corchorus leaves were higher at 10 and 12 WAP. Potassium, sodium, and iron were slightly higher at 4 WAP. The phytate ranged from 18.27 to 25.99 (mg/100 g), phenolic compounds from 1158.38 to 1366.20 (mg/100 g), oxalate from 5.01 to 7.44 (mg/100 g), and saponin from 9.34 to 9.99 (mg/100 g). The phenolic compounds and saponins of the leaves at 4, 10, and 12 WAP were statistically similar. The tender and newly formed Corchorus leaves at 10 and 12 WAP should be utilized for human dietary preparations and livestock feed.