Browsing by Author "Siwela, Mthulisi"

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    Decontamination of aflatoxin-contaminated maize by dehulling
    (Society of Chemical Industry., 2005) Siwela, Andrew H.; Siwela, Mthulisi; Matindi, Gibson; Dube, S.; Nziramasanga, Nozipho
    Dehulling of maize grains as an aflatoxin decontamination method was investigated. Sixty kilograms of maize (whose average moisture content was 110 g kg−1) were thoroughly mixed and divided into two samples. The kernel moisture content of one sample was adjusted to 200 g kg−1 while the other (control) was left at 110 g kg−1. The two samples were kept at ambient temperature (25–30 ◦C) for 21 days. Twenty sub-samples, ten from each, were further divided into two so that one lot was dehulled while the other was not dehulled. These sub-samples were then milled to pass through a 1mm screen and the meal was evaluated for aflatoxin contamination. It was found that there was a 92% decrease in aflatoxin levels in dehulled maize meal compared with undehulled maize meal. We therefore suggest that dehulling the grain can be used to reduce aflatoxin levels in maize.
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    Yeasts and related microorganisms isolated from ripe marula fruits (Sclerocarya caffra) in Zimbabwe
    (SCIELO South Africa, 2005) Okagbuea, R.N.; Siwela, Mthulisi
    The yeasts and related flora associated with ripe fruits of the marula tree in Zimbabwe were isolated and identified as Aureobasidium pullulans, Geotrichum capitatum, Trichosporon brassicae, Rhodotorula mucilaginosa, Hansenula anomala, Hansenula jadinii and Hansenula species. The physiological characteristics of the organisms suggest that, generally, they are not important in traditional marula wine fermentation. The Hansenula spp. are fermentative, however, and may play a role in marula wine-making.