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Proximate and Mineral Composition of Nigerian Leafy Vegetables
S. S. Asaolu,O. S. Adefemi,I. G. Oyakilome,K. E. Ajibulu
Journal of Food Research (JFR) , 2012, DOI: 10.5539/jfr.v1n3p214
Abstract: Proximate analysis and mineral composition of some Nigerian leafy vegetables: bitter leaf (Veronia amygdalina L), India spinach (Basella alba L), bush buck (Gongronema latifolium), scent leaf (Ocimium grastissimum), Smooth amaranth (Amaranthus hybridus), Roselle plant (Hibiscus sabdariffa) and fluted pumpkin (Telfaria occidentali) were carried out using standard analytical procedures. The moisture content of the samples ranged between 10.0-12.08 %, crude protein, crude fibre, crude fat, ash contents and carbohydrate ranged between: 46.56 and 66.60, 4.02 and 12.08, 3.51 and 14.02, 5.02 and 15.55, 1.16 and 15.79 % dry matter (DM). Mineral element analysis showed that the leafy vegetables contained high levels of calcium (63.36-110.16), magnesium (27.51-288.65), sodium (15.01-88.00) and potassium (16.85-168.96) and low levels of copper (nd-3.14), nickel (2.32-18.16) and manganese (2.54-10.06) mg/100g respectively. The study showed that the leafy vegetables examined contained high levels of crude protein with low fat content and crude fibres.
Trace Metals Distribution in Some Common Tuber Crops and Leafy Vegetables Grown in the Niger Delta Region of Nigeria
Ekeanyanwu C. Raphael,Opia E. Eunice,Etienajirhevwe O. Frank
Pakistan Journal of Nutrition , 2010,
Abstract: The main sources of trace metals to plants are the air and soil media from which trace elements are taken up by the root or foliage. Understanding the distribution of some trace metals in some common leafy vegetables and tuber cops is important for establishing baseline concentrations from which anthropometric effects can be measured. The trace metal distribution in some selected leafy vegetables and tuber crops in our study area were determined in samples that were dried, milled and digested. All the minerals investigated were found present in all the components of the selected vegetables and tuber crops. Iron was the most abundant mineral in the vegetables with concentrations ranging between 0.32mg/kg in Ocimum gratissum root to 9.7 mg/kg in Telfaria occidentalis roots. In the root tubers, zinc was the most abundant mineral ranging from 0.62 mg/kg in Manihot esculenta stem to 1.97 mg/kg in Manihot esculenta leaf. The bioconcentration factor indicates that the roots of the food crops concentrate most of the metals than the stems and leaves.
The effect of processing and preservation methods on the oxalate levels of some Nigerian leafy vegetables
EO Ogbadoyi, HA Makun, RO Bamigbade, AO Oyewale, JA Oladiran
Biokemistri , 2006,
Abstract: Titrimetric analysis was used to estimate the level of oxalate in some Nigerian leafy vegetables treated in different ways in two sets of experiments. The treatments were boiling with retention of the water used for boiling, and freezing followed by boiling without retention of the water used for boiling. Results obtained showed that the former in which five different vegetables were used led to significant increases (p<0.05) in the oxalate content of the vegetable preparations. The exception was Vernonia amygdalina in which there was a significant decrease in the oxalate content after boiling. The latter in which three selected vegetables were used however led to significant decrease (p<0.05) in the level of oxalate of the vegetable preparation, a significant amount having been lost in the decanted water. Boiling and then discarding the water used for boiling vegetables provides a good means of reducing the oxalate content of leafy vegetables and consequently the associated food safety problems.
Antioxidant Activity of Selected Nigerian Green Leafy Vegetables
O.A. Odukoya,S.I. Inya-Agha,F.I. Segun,M.O. Sofidiya
American Journal of Food Technology , 2007,
Abstract: Antioxidant activity of hot water extracts of 21 Green Leafy Vegetables (GLV): Amaranthus hybridus Linn. (Amaranthaceae), Amaranthus caudatus (Amaranthaceae), Beilschmedia manni (Meisn.) Benth. Et Hook.f. (Lauraceae), Celosia argentea var argentea (L.) O. Kuntze (Amarantheceae) Celosia argentea var cristata Linn. (Amarantheceae), Corchorus olitorius L. (Tiliaceae), Crassocephalum crepidioides (Benth). S.Moore (Asteraceae), Gnetum bucholzianum Welw. (Gnetaceae), Gongronema latifolium Benth. (Asclepiadaceae), Heinsia crinita (Afz.) G. Taylor (Rubiaceae), Hibiscus callyphyllus Cav. (Malvaceae), Lasianthera africana P. Beauv (Icacinaceae), Myrianthus arboreus P. Beauv. (Urticaceae), Pterocarpus mildbraedii Harms (Papilionaceae), Pterocarpus santalinoides DC. (Papilionaceae), Solanum macrocarpon L. (Solanaceae), Solanum melongena Linn. (Solanaceae), Struchium sparganophora (Linn.) O. Ktze (Asteraceae), Talinum triangulare (Jacq.) Wild. Portulacaceae, Telferia occidetalis Hook (Curcurbitaceae) and Vernonia amygdalina Del. (Asteraceae) was investigated. Potential free radical scanvenging activity of these vegetables was confirmed by spraying spots of the extracts with DPPH (yellow color on purple background). Antioxidant activity was assayed in linoleic acid model system. Total polyphenols as Tannic Acid Equivalent (TAE) and ascorbic acid were evaluated spectrophotometrically. The activity of each extract was calculated as %inhibition of lipid peroxidation. The extracts showed marked antioxidant activity in linoleic acid model systems. Antioxidant values (AA) ranged from as low as 3.67% in A. hybridus to as high as 68.41% in C. argentea var cristata. Phenol content (TAE) varied from 21.83 mg/100 g dry weight in T. triangulare to 546.97 mg/100 g dry weight in G. bucholzianum. Ascorbic acid content (ASC) was from 13.41 mg/100 g dry weight in V. amygdalina to 187.11 mg/100 g dry weight in G. latifolium. There was low correlation between AA/TAE (R2 = 0.432), AA/ASC (R2 = 0.28) and TAE/ASC (R2 = 0.35), respectively.
Effect of Processing on the Vitamin C Content of Seven Nigerian Green Leafy Vegetables
Olubukola Babalola,O .S. Tugbobo and A.S. Daramola
Advance Journal of Food Science and Technology , 2010,
Abstract: This study was designed to determine the effect of processing on the Vitamin C content of seven Nigerian green leafy vegetables, Telfaria occidentalis (ugu), Talinum triangulare (waterleaf), Basella alba (indian spinach), Celosia argentea (soko), Vernonia amygdalina (bitter leaf), Amaranthus hybridus (tete) and Crassephalum crepidioees (rorowo). Processing methods employed are, blanching, boiling, sundrying, squeezewashing, squeeze-washing with salt and squeeze-washing with boiling. Raw ugu had highest Vitamin C content of 62.50 mg/100g while raw waterleaf had the lowest value of 9.30 mg/100g. Blanching and boiling reduced the Vitamin C content of soko and tete tremendously with a value of 91.50% reduction for boiled tete. The percentage loss for sundried vegetables was the lowest when compared with other processing methods with a reduction of 6.50 and 12.40% in indian spinach and rorowo, respectively. Squeeze washing reduced the Vitamin C content of ugu from 62.50 mg/100g to 6.47 mg/100g (89.65%) and bitter leaf from 42.40 mg/100g to 4.28 mg/100g (89.90%). Squeeze-washing followed by boiling of bitter leaf reduced the Vitamin C content from 42.40 mg/100g to 2.18 mg/100g recording the highest loss of 94.90% when compared with other processing methods.
Leafy Vegetables as Potential Pathways to Heavy Metal Hazards  [PDF]
C. E. Anarado, C. J. O. Anarado, M. O. Okeke, C. E. Ezeh, N. L. Umedum, P. C. Okafor
Journal of Agricultural Chemistry and Environment (JACEN) , 2019, DOI: 10.4236/jacen.2019.81003
Abstract: The effect of anthropogenic activity relating to industrial and economic development has had a detrimental impact on the environment and human health, and hence the need for continued research. Five common African vegetablesMurraya koenigii, Ocimum gratissimum, Amaranthus hybridus, Capsicum annuum and Moringa oleifera were used to study absorption of Lead, Cadmium, Cobalt and Zinc from soils inoculated with metal ions. 0.1 M and 0.5 M solutions of the metal ions were used in the inoculation. Each of the plants was collected in the first instance at 8 weeks, and then at 10 weeks of inoculating. Atomic Absorption spectrophotometer was used to determine the metal ions concentrations absorbed in the plants. Cd2+ was most and Moringa oleifera the least absorbed of the four metal ions, with a highest value of 34.801 ± 0.805 mg/kg occurring in Capsicum annuum. Co
Heavy Metal Contamination in Green Leafy Vegetables Collected From Different Market Sites of Kathmandu and Their Associated Health Risks  [PDF]
Pawan Raj Shakya,Neena Malla Khwaounjoo
Scientific World , 2013, DOI: 10.3126/sw.v11i11.8550
Abstract: The present study was carried out to assess contamination of five heavy metals (As, Cd, Cr, Pb and Zn) in five different types of green leafy vegetables viz. , mustard ( Brassica campestris ), garden crees ( Lepidium sativum ), fennel ( Foeniculum vulgare ), coriander ( Coriandrum sativum ), and spinach ( Spinacea oleracea ) collected from different market sites of Kathmandu. Atomic absorption spectrometer was used to determine the concentrations of these metals in a total of 45 test vegetables. Results showed a substantial accumulation of heavy metals in roots and leafy shoots of the vegetables. The range of various metals was 0.9-12.0, 2.7-12.5 and 16.8-158.7 mg kg-1 in roots and 3.2-19.1, 5.3- 32.9 and 23.9-223.1 mg kg-1 in leafy shoots of the test vegetables for Cd, Pb and Zn respectively. However, the levels of As and Cr were found below the detection limits. Results revealed that the average concentrations of all metals (both leafy shoots and roots together) in the vegetables were found in order of their abundance as Zn>Pb>Cd. It was also found that Pb and Cd levels exceeded the maximum permissible limits set by FAO/WHO for human consumption. Daily intake of heavy metals through consumption of the vegetables was also investigated. From the present study, we conclude that a monitoring plan and a health risk assessment are necessary to evaluate the levels of metal concentration in vegetables in order to develop the proper measures for reducing excessive build-up of these metals in the food chain. Scientific World, Vol. 11, No. 11, July 2013, page 37-42 DOI: http://dx.doi.org/10.3126/sw.v11i11.8550
Trace Metal Contents of Vegetables and Fruits of Hyderabad Retail Market  [PDF]
F. Ismail,M.R. Anjum,A.N. Mamon,T.G. Kazi
Pakistan Journal of Nutrition , 2011,
Abstract: The heavy metals or trace elements play vital role in the metabolic pathways during the growth and development of plants, when available in adequate concentration. Seasonal fruits and vegetables play a significant role in human nutrition. Food production and its safety is an important aspect of the measure of any nations growing economy and it is a popular trend to find out the trace metal contents of vegetables and fruits of local markets throughout the world but still data is lacking in developing countries like Pakistan. The trace metals Co, Zn, K, Na, Fe, Mn, Ca, Mg, Cu, Ni were analyzed in 15 vegetables and fruits (okra, guava, banana, potato, chili paper, onion, tomato, mint, mango, ginger, brinjal, bitter gourd, spinach, carrot) available in the markets of Hyderabad city. Vegetables and fruits selected for the study are commonly consumed by all income groups of Hyderabad city. Mineral contents were determined using Atomic Absorption Spectrometry (AAS). Co was analyzed 0.1038-0.126 mg/100 gm, Zn was 0.44-0.55 mg/100 gm, K 2.3-38.5 mg/100 gm, Na was 1.5-2. Mn was 0.0526-0.1435 mg/100 gm, Ca 0.3-3.35 mg/100 gm, Mg 1.191-32.0 mg/100 gm while Cu 0.1-1.9 mg/100 gm and Ni 0.05-0.18 mg/100 gm where as Fe was found 1.5-29.0 mg/100 gm among all selected vegetables and fruits.
Journal of Applied Technology in Environmental Sanitation , 2012,
Abstract: Heavy metal contamination of vegetables poses a threat to consumers' welfare. This study aims to determine the lead concentrations in leafy vegetables sold in selected markets in Metro Manila, Philippines. About five randomly sampled leafy vegetables obtained from two private markets in Metro Manila were examined for their lead concentrations. All vegetables bought in the private markets had lead concentrations. Most leafy vegetables obtained had low lead concentrations. Significant differences on the lead concentrations in all leafy vegetables obtained in the different markets were found (p < 0.05). The contamination of vegetables with lead in elevated levels may have potential health hazards to consumers. Proper washing of vegetables before consumption may help reduce the health risk.
African leafy vegetables in South Africa
WS Jan van Rensburg, W van Averbeke, R Slabbert, M Faber, P van Jaarsveld, I van Heerden, F Wenhold, A Oelofse
Water SA , 2007,
Abstract: In this article the term ‘African leafy vegetables’ was adopted to refer to the collective of plant species which are used as leafy vegetables and which are referred to as morogo or imifino by African people in South Africa. Function is central in this indigenous concept, which is subject to spatial and temporal variability in terms of plant species that are included as a result of diversity in ecology, culinary repertoire and change over time. As a result, the concept embraces indigenous, indigenised and recently introduced leafy vegetable species but this article is concerned mainly with the indigenous and indigenised species. In South Africa, the collection of these two types of leafy vegetables from the wild, or from cultivated fields where some of them grow as weeds, has a long history that has been intimately linked to women and their traditional livelihood tasks. Among poor people in remote rural areas the use of these types of leafy vegetables is still common but nationwide there is evidence of decline, particularly in urban areas. Cultivation of indigenous or indigenised leafy vegetables is restricted to a narrow group of primarily indigenised species in South Africa. Seven groups of indigenous or indigenised African leafy vegetables that are important in South Africa were given special attention and their local nomenclature, ecology, use and cultivation are discussed.
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