Influence of storage on chemical, microbial and consumer acceptability of a milk-like product made from melon seeds

The storage stability of melon milk at room (30 +/- 2 degrees C) and refrigeration (10 +/- 2 degrees C) temperatures was determined by analyzing changes in the chemical, microbial and sensory properties of the milk stored for 7 days. The results showed that at both storage temperatures, soluble solids and pH of the milk decreased while titratable acidity increased with storage. The standard plate counts increased appreciably while coliforms were absent in the milk with storage at both storage temperatures. The overall acceptability score of the melon milk dropped during storage, the drop being faster at 30 +/- 2 degrees C than at 10 +/- 2 degrees C. The milk samples stored at 30 +/- 2 degrees C and 10 +/- 2 degrees C were acceptable only within one and three days, respectively; thereafter, they were unacceptable.

Quality attributes of fermented yam flour supplemented with processed soy flour

Pretreated soy flour was used to replace 10, 20, 30 and 40% of fermented yam flour as a protein supplement. The effect of the supplementation on the physicochemical and sensory properties of 'amala', a popular West African food made from rehydrated yam flour, was investigated. Blanching (10 min in boiling water) and subsequent fermentation (24 h) as pretreatment methods produced flour that was lighter in color than the unfermented samples. Protein content of the yam-soy mixture increased from 3.5% in the control to 19.7% for 40% soy fortification. Water binding capacity increased from 212.6 g/100 g for the yam flour control to 257.3 g/100 g for the blend with 40% soy flour. However, swelling capacity and solubility were adversely affected with increased soy flour addition as dough became sticky and soft. There was no significant difference in color, taste, flavor or overall acceptability when compared with the control up to 20% soy substitution. Dough with 20% soy flour is a possibility for increasing the protein content of yam flour in human feeding.

Microbial populations associated with the retting of melon pods (Colocynthis citrullus L.) during seed recovery

The traditional process for the retting of melon pulp and microbiological characteristics in the recovery of melon seeds (Colocynthis citrullus L.) were investigated. Melon pods were sliced open and exposed for seven days. The pulp underwent a natural fermentation that was characterized by the growth of microorganisms to 10(8)-10(10) cfu/g. The pH fluctuated between 4.8 and 5.1 with a lactic acid content of 0.72%. Bacillus subtilis, B. polymyxa, Lactobacillus fermentum, L. brevis and Streptococcusfaecalis were the predominant microorganisms but, significant contributions were made by Staphylococcus saprophyticus and Enterobacter cloacae. Penicillium, Aspergillus and Rhizopus species including the yeasts, Saccharomyces cerevisiae, Candida krusei and Deboromyces hansenii were isolated from the fermentation. Growth of microorganisms was completely inhibited in antibiotic-treated samples indicating that the melon pods were the main source of microorganisms for the fermentation.

Microbiology of 'obiolor': a Nigerian fermented non-alcoholic beverage

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.