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Okpiye is a food condiment prepared by the fermentation of Prosopis africana seeds. The traditional process for the production and microbiological characteristics of the condiment were investigated. During laboratory fermentation that lasted 96 h, the mesquite seeds underwent a natural fermentation that was characterised by the growth of microorganisms to 10(6)-10(8) cfu/g. Several species of bacteria especially B. subtilis, B. licheniformis, B. megaterium, Staphylococcus epidermidis and Micrococcus spp were found to be the most actively involved organisms. However, significant contributions to the microbial ecology were made by Enterobacter cloacae and Klebsiella pneumoniae. Lactobacillus spp were present in low numbers towards the end of the fermentation. The presence of Proteus and Pseudomonas spp in traditional fermented samples demonstrate the variability which may exist in the microflora of individual fermented samples. Variations in the important microbial groups show that Bacillus spp were the most prevalent species and occurred until the end of fermentation. Temperature, pH and titratable acidity varied with time and were influenced by the metabolic activities of the microorganisms.

Obiolor is an acidic non-alcoholic beverage prepared by fermenting sorghum and millet malts. The traditional process for the production and microbiological characteristics of the beverage were investigated. Bacillus spp., Lactobacillus plantarum and Streptococcus lactis were the associated micro-organisms most actively involved. Yeasts were present in low numbers towards the end of the fermentation. Other micro-organisms isolated did not appear to play a role in the fermentation process. Variations in the important microbial groups involved and their metabolic products were studied. Titratable acidity increased gradually until the end of the fermentation while the total soluble solids and pH declined. Acetobacter spp. were probably responsible for the unacceptability of the product after 24 h.

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A water-soluble gum was extracted from the endocarp capsule of the seed coat of Prosopis africana. The gum yield varied substantially with the method of dehulling. Maximum yield was obtained after boiling in 0.1 m Na 2 CO 3 for 4 h. The effects of two different gum concentrations on the rheological properties of gum solutions were examined. The gum formed viscous solutions at low concentrations and exhibited stable viscosity in the pH range 6.0-8.0. Chemical analyses showed that the purified gum had a composition of 2.4% fat, 1.04% protein, 21.5% crude fibre and a gelation concentration of at least 10%. Galactose and mannose were the major polysaccharides identified. Large reductions in viscosity were observed with the addition of various concentrations of Na + salts. The activation energies of flow for 2 and 3% gum solutions were in the range of 19.2-22.8 kJ mol )1 and were characteristic of systems with little intra-and intermolecular interactions.