The Nutritive Value of Commonly Consumed Processed and Unprocessed Vegetables in South-Southern Nigeria

Aim: The nutritive value, proximate, vitamin and mineral compositions of seven commonly consumed vegetables in South-Southern Nigeria were determined.

Methodology: Pods and leaves of vegetables were divided into two parts. One part was analyzed raw and the remaining part was cooked by boiling. The raw vegetable leaves and okro pods were separately washed and dried using a food dehydrator (40ºC) for 24hrs. After drying, it was milled into fine flour using an electric blender. The second part of the vegetables were processed by boiling using variable time, after boiling, they were separately drained and dried using a food dehydrator at a temperature of about 50ºC for 48 hrs. Chemical analyses were carried out using standard laboratory methods. Means and standard deviations were calculated using the statistical package for social science. The least significant difference (LSD) was accepted at P = .05 significance.

Results: For the raw vegetables the results were as follows: Moisture 71.2 – 91.2%, ash 0.9- 2.9%, dietary fibre 9.2 – 13.1%, fat 0.3 -1.4%, protein 2.1 – 8.2%, available Carbohydrate 1.0 – 8.7%, phosphorus 8 -52 mg/100 g, potassium 263- 1152 mg/100 g, sodium 3-23 mg/100 g, calcium 183-815 mg/100 g, magnesium 67-217 mg/100 g, iron 0.26-1.27 mg/100 g, zinc 0.26-1.10 mg, folate 3-13 mcg/100 g. The results of the boiled vegetables were: moisture 80.9– 93.8%, protein 1.7 – 3.2%, fat 0.2 – 0.5%, ash 0.5– 1.1%, dietary fibre 3.9 – 9.3%, available carbohydrate 3.8 – 9.9%, phosphorus 7 – 35 mg/100 g, Potassium 0.33 – 300 mg/100 g, sodium 0.3 – 20 mg/100 g, magnesium 45 – 132 mg/100 g, calcium 82 – 200 mg/100 g, iron 0.21 -0.60 mg/100 g, zinc 0.13 – 0.30mg/100g. Folate 3 – 6 mcg/100 g. The range of the percentage contributions of the vegetables that are consumed raw to the recommended nutrient intake or recommended dietary allowance of adults are as follows: protein 5-18%, fat 1-3%, carbohydrates 1-6%, dietary fibre 3-52%, iron 2-14%, zinc 6-36%, calcium 26 -116%, phosphorus 8-31%, sodium 0.3-1%, Potassium 8-32%, Magnesium 26-99%, Folate 3-4%.

Conclusion: Boiling significantly reduced most nutrient studied. Bitter leaves are more nutrient dense than other studied vegetables. Knowing the food compositions of these vegetables will promote their use.