Screening South African Potato; Tomato and Wheat Cultivars for Five Carotenoids

In South Africa malnutrition is of great concern. Vitamin A deficiency is one of the leading causes of infections as a result of micronutrient malnutrition. Although supplementation and food fortification programmes exist; these either are not available or are unaffordable to communities in remote rural areas. The selection of crops that are naturally rich in provitamin A (a-carotene) and other carotenoids that can be recommended to small-scale farmers for breeding and for food production; could be an effective way to address vitamin A deficiencies and associated diseases. The aim of this study was to profile two cultivars each of potato; tomato; bread wheat and durum wheat; which are highly consumed crops in South Africa; for their carotenoid content using high-performance liquid chromatography. To this effect; reliable extraction and quantification of five carotenoids lutein; zeaxanthin; canthaxanthin; a-carotene and lycopene were performed for these crops. Lutein and zeaxanthin were found to be the major carotenoids in potato; whilst lycopene was the major carotenoid in tomato. In durum wheat; only lutein and zeaxanthin were identified whilst bread wheat contained lutein; zeaxanthin and a-carotene. The methodology used proved to be robust and suitable to screen a large number of potato; tomato and wheat cultivars for their carotenoid content

Economic and Health Perspectives of Mycotoxins: A Review

Due to their potent toxicity; mycotoxins have attracted worldwide attention over the years and recently; there has been an increasing disquietness on the part of governments; producers; processors; marketers and consumers over the health and economic significance. The diversity in occurrence; structure and chemistry of mycotoxins make their impact more complex to diagnose. Owing to their usual environmental conditions of production in countries with warm and humid climates as well as poor conditions of storage and handling; agricultural commodities are susceptible to fungal colonization and development which can lead to the accumulation of mycotoxins. As part of drying process; agricultural produce are exposed to contamination by ubiquitous mycoflora that grow; develop and produce some toxic metabolites that are harmful to the consumers. Food is already a limited commodity; especially in developing countries of the world and consumers therefore; either as a matter of choice or for the relative cheapness and affordability during periods of scarcity; opt for the over-fresh produce; sometimes not aware of the adverse health implications such foods pose. In the quest to ensure regular and continuous availability of certain perishable farm produce; especially in developing nations; local farmers and traders resort to unscientific and faulty storage conditions to preserve commodities; thereby pre-disposing produce to fungal colonization and mycotoxin production. Thus; commodities such as groundnuts; maize; sorghum; rice; yam; cassava; tiger nut; soyabeans; cotton seeds; fruits; vegetables spices can be contaminated with toxins of fungal origin such as aflatoxins; ochratoxins; fumonisins; patulin; sterigmatocystin; deoxynivalenol; zearalenone and other mycotoxins which pose serious economic and health risks. This review presents some mycotoxins commonly found on agricultural commodities both in temperate and tropic regions of the world. The acute and chronic toxic effects of these toxins in humans and animals are highlighted. Control measures include education of the populace on the risks of exposure to mycotoxins through skin contact; inhalation and ingestion; early harvesting; rapid appropriate drying; sequestration of diseased seeds from sound seeds; sanitation; use of good agronomic practices; insect control; the use of botanicals and synthetics as storage protectants; biological control and detoxification of mycotoxin-contaminated commodities. Probable related health implications are also discussed with a view to creating better public awareness and providing scientific basis for appreciating the challenges; while proactively promoting the development and implementation of policies at mitigating risk factors. Some mycotoxins; their producer fungi and toxic effects are further presented

Effect of land use changes on some important soil properties in cotton-based farming system in Burkina Faso

Continuous and intensive cropping without restoration of soil fertility has depleted the nutrient base of most soils in the semi arid zone. A field survey was carried out in 2000 in Bala village in the cotton production zone of western Burkina Faso to assess the effect of land use changes on soil chemical and physical changes. The methodology consisted of land use analysis at contrasted periods; field sampling and measurements; and farmers' interview. Land use analysis was done at three periods: 1952; 1981 and 1999. Soil samples were taken in farmers' fields selected on the basis of their equipment level and the cultivation duration. Two fallows were selected and considered as control situation. Aerial photos analysis showed that the proportion of the land under cultivation was increased at about 38.3 from 1952 to 1999. Soil chemical analysis showed that soil total P and K were significantly higher in soils manually cultivated than in soils cultivated with animals and tractors. Soil pH was lower in motorized farmers' fields than in the other categories. Soil organic matter and N content were not affected by all the studied factors. The percentage of sand in the soil increased with the performance of the equipment. The opposite situation was observed with soil silt content. Soil stability was not significantly affected by any of the factors. But the numerical values showed a more stable soil structure under fallows than when soils were cultivated. From the results; it appeared that the fundamental cause of land degradation in the area is the farming system than the nature of the crop being grown