Effect of Drying Methods on the Nutrient and Phytochemical Properties of Some Cultivated and Wild Leafy Vegetables
Effect of Drying Methods on the Nutrient and Phytochemical Properties of Some Cultivated and Wild Leafy Vegetables.
ABSTRACT
The aim of this study was to determine the nutrient and phytochemical composition ofmfresh, sun and shade dried okra, bitter, scent, G. latifolium and roselle leaves. The vegetables were purchased from two markets. Okra, bitter, scent and G.latifolium leaves were purchased from Nsukka and roselle leaves were bought from Jos market.
All the vegetables were washed, weighed and divided into two equal parts. Each part was sun, or shade dried, pulverized, packed and stored. The fresh samples for each of the vegetables served as control. The fresh, sun and shade dried samples of all the vegetables were separately analyzed for various nutrient and phytochemicals on dry weight basis using standard assay techniques.
Data generated were statistically analyzed. The means were separated and compared. All the fresh samples had high moisture values(Okra leaf; 62.22%, bitter leaf; 62.32%, scent leaf; 62.46%, G.latifolium; 61.44% and roselle leaf; 85.53%) . The moisture content of the sun and the shade dried samples differed (P<0.05).
The exception was that of roselle whose sun and shade dried values were comparable (6.36 and 6.38%) (P>0.05). Fresh samples of all the vegetables had lower protein. The processed okra, bitter, scent and roselle leaves had comparable values (P>0.05). Moisture lost due to drying increased nutrient density of the vegetables, especially the roselle leaves.
The phytochemicals (Tannins, phytate, saponins and flavonoid) of the fresh samples were higher than those of the sun and the shade dried samples. This showed that fresh vegetables are better sources of phytochemicals as against the sun and the shade dried samples.
INTRODUCTION
Man must eat to survive for the continuity of the human race. The foods for human consumption are of both plant and animal origin.Cereals, legumes, roots, tubers, suckers, oils, nuts, fruits and vegetables are plant foods. Meat, milk, eggs and oils are animal products.
Both plant and animal foods contain nutrients. Oxford Medical Dictionary (2003) defines nutrients as substances that must be consumed as part of the diet to provide energy, protein for growth or substances that regulate growth or energy production.
Carbohydrate, proteins, fats, vitamins, minerals and water are the existing six nutrients. It is known that too much or too little of these nutrients have adverse effects on health. The source of these nutrients equally determines how healthy one is.
A typical example is in the case of fats. Animal fat contains about 40-60% of fat as saturated fatty acids. Plant oils contain mostly unsaturated fatty acids ranging from 73 to 94% of total fat (Wardlaw & Kessel, 2002). Plant oil is the most beneficial to health.
Current studies showed that plant nutrients are not inferior to animal nutrients as it was earlier thought. In addition, plants contain other non-nutritive dietary components that are beneficial to health. These components are called phytochemicals. “Phyto” because they are only found in plant based foods (Pamplona-Roger, 2005).
The present study concentrated on nutrient and phytochemical levels of five cultivated and wild vegetables. Vegetables are generally herbaceous (non-woody) plants that are cultivated in farms, collected from forest trees, market and home gardens as well as kitchen gardens for home use.
REFERENCES
Afolabi, F. E. (2007). Chemical composition and antibacterial activity of Gongronema Latifolium. Journal of Zhejiang University Science, 8 (5), 352-358.
Aletor, M.V.A., &Adeogun, O.A. (1995) Nutrient and antinutrient components of some tropical leafy vegetables. Food Chemistry, 53,375-379.
Anonymous. (1999, September 4). Retrieved April 18, 2010, from http://bkbchina. com/fidility/bitter.htm.
AOAC. (1995). Official Method of Analysis of the Association of Official analytical Chemists. (15th Ed.). Washington D.C; Association of Official Analytical Chemists.
Be Healthy Enterprises INC. (2009, January 17). Colour Matters. Retrieved October 5, 2009, from, http://www.behealthyenterprise.com/colour-matters.
Bender, D. A (2002). Introduction to Human Nutrition ed Micheal J.G, Hester, H.V. & France J. Blackwell Publishing London.
CSN Team.
