Influence of ginger on sensory properties and shelf-life of ogi, a Nigerian traditional fermented food

Abstract

The influence of ginger on fermentation, acceptability and shelf life of ogi (maize pap) was investigated. Various concentrations (1, 5 or 10%) of milled oven-dried ginger were incorporated into ogi at the beginning of fermentation. Physico-chemical and microbiological changes during fermentation and storage were determined. The pH of ogi samples decreased steadily and ranged between 4.08 and 5.80 and titratable acidity (TA) ranged between 0.20 and 0.77% at the end of fermentation (48 h). The lactic acid bacteria (LAB) count (log cfu/ml) ranged between 6.58 and 6.96 while the yeast count (log cfu/ml) ranged between 5.76 and 7.84. Sensory evaluation of cooked ogi samples revealed that high
concentration of ginger (10%) adversely affected acceptability. Therefore, sample B (containing 5% ginger) was rated best in all the parameters tested. During storage, there was a slight decrease in pH of the samples which ranged between 3.27 and 3.65 while TA ranged between 0.009 and 0.12%. Sample D (containing no ginger) had the highest coliform count of 6.83 log cfu/ml while sample C (containing 10% ginger) had the lowest count of 6.49 log cfu/ml. Sample D also had the highest mould/yeast count of 9.81 log cfu/ml while sample C had the lowest (9.20 log cfu/ml).The total viable count ranged between 9.51 log cfu/ml (sample C) and 10.20 log cfu/ml (sample D) at the end of 8 days of storage. This study revealed that incorporation of 5% ginger into ogi significantly improved its sensory attributes, led to a relatively reduced microbial load during storage and hence an improvement in the shelf stability of the
product.