Identification, consumption pattern and nutrient composition of processed green leafy vegetables and their yam dishes

Thesis Abstract

The thrust of this work was to identify some popular and lesser-known cultivated and forest green leafy vegetables consumed in Igbo-ukwu, Aguata LGA, Anambra State, Nigeria. Those identified include ugbogulu, eliemionu, ariraa, okpa okuku, ugu oyibo and abuba ji nwannu, used in this study. These vegetables were purchased in bulk from Igbo Ukwu daily market, cleaned and divided into 3 portions. Fresh portions served as the controls. The sun and the shade dried samples were the processed portions.These cleaned vegetables and their products were analysed for various nutrients, antinutrients and food toxicants using standard methods. Both nutrient contents of the vegetables and their dishes as well as the organoleptic attributes of the dishes were ascertained. The data generated from both the vegetable and their yam dishes were analysed using percentages, means, standard deviation and the standard error of the mean. New multiple Duncan’s studentized range test was applied to separate and compare means.

Ugbogu, ( Cucurbita pepo), ariraa. ( Corchorus trideus tiliaceae) eliemionu. (Celosia Argentea), ugu oyibo. (Jatropha aconitifolia), okpa okuku (Uvaria chamae) and abubaji nwannu ( Ipomoea batatas) were identified by Igbo-ukwu women as wild and cultivated edible vegetables. Both parents and grandparents form major sources of information about cultivation, harvesting, processing, preparation and utilization of yam dishes based on these vegetables. These vegetable are on the verge of extinction due to poor nutrition education, migration of youths and young adults, seasonality,change in lifestyles, nutrition transition and food habits. Sun and shade drying increased many nutrients such as protein from 10.70 to 19.40%. These processes also increased some micronutrients. Iodine, copper, and calcium increased from traces to5.08 and 4.43mg; 0.2 to 2.4 and 1.7mg; from 0.2 to 11.5 and 22.00mg, respectively.These processes increased phytate, oxalate, tannins and saponins from 0.00mg to 125.58 and 116.5mg; traces to 135.50mg and 112.3mg; traces to 0.15 and 0.16mg and from traces to 0.05 and 0.05mg, respectively.

The yam dishes prepared with fresh, sun and shade dried, as well as pulverized vegetables had increased protein from 5.4 in A-102 –yam dish prepared with sun dried ugu oyibo to 12.6% in A-101 –yam dish prepared with shade dried and ash from 4.6 in A-103- yam dish prepared with shade dried okpa okuko to 9.50% in A-105-yam dish prepared with fresh sweet potato.. These dishes had traces of phytate, oxalate,tannins and saponins. However, dish prepared with sun dried ugu oyibo leaves hadincreases in phytate oxalate, tannins and saponins and food toxicants from (traces to1.21,4.34,16.6 and 14.5g, respectively).Iron, zinc, copper and calcium in these dishes increased. Iron increased from 3.5 to 33.5mg, zinc from traces to 4.2mg, copper from traces mg to 1.4mg and calcium from 2.00 to 25.50mg, respectively. The dishes prepared with fermented oil bean seeds, fresh okpa okuku leaves and fresh sweet potato leaves had increases in beta-carotene that ranged from traces to 52.00, 25.3 and 24.9mg each.The dishes prepared with fresh sweet potato leaves and that prepared with fresh ugu oyibo leaves had the best organoleptic attributes and general acceptability. (7.5 and 7.3,respectively).