Optimation of Ontaku/ Oshikundu: Pearl millet and sorghum malts quality and conveniet premix development
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Date
2020
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Publisher
University of Namibia
Abstract
Oshikundu/Ontaku is a nonalcoholic, acidic, opaque fermented beverage. It is comprised of pearl millet (Pennisetum glaucum (L.) R. Br) meal/flour, commonly known as mahangu, malts of pearl millet or sorghum (Sorghum bicolour (L.) Moench) and/or brans (pearl millet). Brewing of oshikundu remains an art in households with no empirical improvement of a controlled fermentation flow process to give a consistent product. Some of the major limitations to the formal commercialisation of this brew are the absence of standardised malting process that gives a consistent malt quality and microbial safety. The lack of standard
ingredient ratios (flour/meal: malt: water) of brewing. Also, the sedimentation of adjunct particles at the bottom (dreg), thus creating the difference in viscosity of oshikundu. Welldefined fermenting microorganisms are not used, and the preparation method still relays on a laborious time-consuming process. Therefore, this study investigated conditions for malting, reduction of dreg, identification of fermenting microorganisms and formulation of ingredient ratio for an improved preparation process. Grains used in the study were collected from Omahenene Agricultural Research Station (20 15 harvest), of the Ministry of Agriculture,
Water and Forestry. Pearl millet varieties Okashana 2 (SDMV 93032), Kantana (landrace) and Kangara (SDMV 92040), while sorghum varieties are Macia (SDS3220) and landrace commonly referred to as red sorghum. Malts of the two cereals were prepared by steeping in static water at 20-22°C for 2 hours wet and 2 hours air-rest for a total of 8 hours and germinated at 30°C. Malts were dried between 50-55°C for 24 hours. Cereals germinative energy was above 90% as recommended for sorghum by the European Brewery Convention. Malting loss was high up to 30% in pearl millet varieties and Macia. Crude protein and fibre
were found . to increase following malting. Reducing sugars were not detected in
nongerminated pearl millet graiJ.'ls. Malts reducing sugars were statistically significant (p ~0.05) between cereals. The malt reducing sugars was as follows Macia> Red sorghum> time reduce dregs. Also, ingredient ratios were formulated by the use of dry ingredients premix for making oshikundu that was easy to prepare.
Description
A research dissertation submitted in fulfillment of the requirements for the Degree of Doctor of Philosophy in Science (Biochemistry)
Keywords
Ontaku/ Oshikundu, Pearl millet, Sorghum